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Effects of Protein Supplements on Muscle Damage, Soreness and Recovery of Muscle Function and Physical Performance: A Systematic Review
Abstract
Protein supplements are frequently consumed by athletes and recreationally-active individuals, although the decision to purchase and consume protein supplements is often based on marketing claims rather than evidence-based research.
To provide a systematic and comprehensive analysis of literature examining the hypothesis that protein supplements enhance recovery of muscle function and physical performance by attenuating muscle damage and soreness following a previous bout of exercise.
English language articles were searched with PubMed and Google Scholar using protein and supplements together with performance, exercise, competition and muscle, alone or in combination as keywords.
Inclusion criteria required studies to recruit healthy adults less than 50 years of age and to evaluate the effects of protein supplements alone or in combination with carbohydrate on performance metrics including time-to-exhaustion, time-trial or isometric or isokinetic muscle strength and markers of muscle damage and soreness. Twenty-seven articles were identified of which 18 dealt exclusively with ingestion of protein supplements to reduce muscle damage and soreness and improve recovery of muscle function following exercise, whereas the remaining 9 articles assessed muscle damage as well as performance metrics during single or repeat bouts of exercise.
Papers were evaluated based on experimental design and examined for confounders that explain discrepancies between studies such as dietary control, training state of participants, sample size, direct or surrogate measures of muscle damage, and sensitivity of the performance metric.
High quality and consistent data demonstrated there is no apparent relationship between recovery of muscle function and ratings of muscle soreness and surrogate markers of muscle damage when protein supplements are consumed prior to, during or after a bout of endurance or resistance exercise. There also appears to be insufficient experimental data demonstrating ingestion of a protein supplement following a bout of exercise attenuates muscle soreness and/or lowers markers of muscle damage. However, beneficial effects such as reduced muscle soreness and markers of muscle damage become more evident when supplemental protein is consumed after daily training sessions. Furthermore, the data suggest potential ergogenic effects associated with protein supplementation are greatest if participants are in negative nitrogen and/or energy balance.
Small sample numbers and lack of dietary control limited the effectiveness of several investigations. In addition, studies did not measure the effects of protein supplementation on direct indices of muscle damage such as myofibrillar disruption and various measures of protein signaling indicative of a change in rates of protein synthesis and degradation. As a result, the interpretation of the data was often limited.
Overwhelmingly, studies have consistently demonstrated the acute benefits of protein supplementation on post-exercise muscle anabolism, which, in theory, may facilitate the recovery of muscle function and performance. However, to date, when protein supplements are provided, acute changes in post-exercise protein synthesis and anabolic intracellular signaling have not resulted in measureable reductions in muscle damage and enhanced recovery of muscle function. Limitations in study designs together with the large variability in surrogate markers of muscle damage reduced the strength of the evidence-base.
... Os aminoácidos das proteínas do soro possuem similaridade com as proteínas do músculo esquelético, permitindo que as proteínas forneçam quase todos os aminoácidos em porpoção similar, gerando um efeito anabólico (KILARA & VAGHELA, 2018;HILKENS et al., 2021). Dessa forma, o consumo de suplementos proteicos durante a recuperação do exercício promove o anabolismo do músculo esquelético, estimulando maiores taxas de síntese proteica miofibrilar e mitocondrial (NELSON et al., 2012;PASIAKOS;LIEBERMAN;MCLELLAN, 2014) . Em teoria, a estimulação da síntese de proteína muscular pela suplementação de proteína representa uma resposta adaptativa crítica do músculo esquelético ao estresse mecânico que auxilia no crescimento e no reparo de proteínas contráteis, facilitando, assim, a recuperação a longo prazo e promovendo a remodelação muscular, de modo que essas alterações na síntese proteica com a suplementação reduzam os índices de dano muscular e acelerem a recuperação da função muscular (PASIAKOS; LIEBERMAN; MCLELLAN, 2014). ...
... Os aminoácidos das proteínas do soro possuem similaridade com as proteínas do músculo esquelético, permitindo que as proteínas forneçam quase todos os aminoácidos em porpoção similar, gerando um efeito anabólico (KILARA & VAGHELA, 2018;HILKENS et al., 2021). Dessa forma, o consumo de suplementos proteicos durante a recuperação do exercício promove o anabolismo do músculo esquelético, estimulando maiores taxas de síntese proteica miofibrilar e mitocondrial (NELSON et al., 2012;PASIAKOS;LIEBERMAN;MCLELLAN, 2014) . Em teoria, a estimulação da síntese de proteína muscular pela suplementação de proteína representa uma resposta adaptativa crítica do músculo esquelético ao estresse mecânico que auxilia no crescimento e no reparo de proteínas contráteis, facilitando, assim, a recuperação a longo prazo e promovendo a remodelação muscular, de modo que essas alterações na síntese proteica com a suplementação reduzam os índices de dano muscular e acelerem a recuperação da função muscular (PASIAKOS; LIEBERMAN; MCLELLAN, 2014). ...
... Os aminoácidos das proteínas do soro possuem similaridade com as proteínas do músculo esquelético, permitindo que as proteínas forneçam quase todos os aminoácidos em porpoção similar, gerando um efeito anabólico (KILARA & VAGHELA, 2018;HILKENS et al., 2021). Dessa forma, o consumo de suplementos proteicos durante a recuperação do exercício promove o anabolismo do músculo esquelético, estimulando maiores taxas de síntese proteica miofibrilar e mitocondrial (NELSON et al., 2012;PASIAKOS;LIEBERMAN;MCLELLAN, 2014) . Em teoria, a estimulação da síntese de proteína muscular pela suplementação de proteína representa uma resposta adaptativa crítica do músculo esquelético ao estresse mecânico que auxilia no crescimento e no reparo de proteínas contráteis, facilitando, assim, a recuperação a longo prazo e promovendo a remodelação muscular, de modo que essas alterações na síntese proteica com a suplementação reduzam os índices de dano muscular e acelerem a recuperação da função muscular (PASIAKOS; LIEBERMAN; MCLELLAN, 2014). ...
Barras de whey protein tornam-se um potencial atrativo para os consumidores por apresentar várias propriedades que trazem benefícios à saúde. Neste artigo, o objetivo é realizar um levantamento sobre a produção científica e tecnológica de whey protein em artigos científicos e patentes no banco de dados. As plataformas de artigos (Scopus, Science Direct e Scielo) e de patentes Espacenet, INPI e Lens foram utilizadas nas buscas para palavras-chave: “protein bars”, “whey protein” e “whey protein bars”, possibilitando coletar dados de publicações/ano (2012-2022). Os Estados Unidos possuem quase 30% de todas as publicações relacionadas a barras de proteína, e em segundo lugar está a China com quase 15%. Já no Brasil, a quantidade de publicações tem crescido nos últimos anos, apresentando em 2017 crescimento em novas tecnologias e novos produtos. Isso mostra uma grande oportunidade para realização de pesquisa e desenvolvimento nessa área, mais especificamente em aditivos para a indústria de alimentos.
... EIMD potentially hinders training adaptations [15] and hence several strategies have been investigated to mitigate EIMD including cryotherapy, massage, stretching, compression garments, electrostimulation [25,26], and dietary manipulation. Dietary strategies have received considerable recent attention, especially regarding supplemental protein-and amino acid-based products provided peri-exercise [27][28][29][30][31][32][33]. ...
... The systematic reviewing of relevant literature has failed to produce definitive conclusions, perhaps due to either overly broad or narrow inclusion criteria [27,31]. No review yet has explicitly analysed studies whereby a variety of protein supplements were consumed in conjunction with resistance exercise. ...
... No review yet has explicitly analysed studies whereby a variety of protein supplements were consumed in conjunction with resistance exercise. Pasiakos and colleagues [31] systematically reviewed studies that utilised varied exercise protocols (resistance and endurance) and provided protein-or amino acid-based supplements. Resistance exercise typically causes more severe EIMD than endurance exercise, although only five of the 27 included studies involved resistance exercise alongside protein consumption [31]. ...
Background
It is unknown whether dietary protein consumption can attenuate resistance exercise-induced muscle damage (EIMD). Managing EIMD may accelerate muscle recovery and allow frequent, high-quality exercise to promote muscle adaptations. This systematic review and meta-analysis examined the impact of peri-exercise protein supplementation on resistance EIMD.
Methods
A literature search was conducted on PubMed, SPORTDiscus, and Web of Science up to March 2021 for relevant articles. PEDro criteria were used to assess bias within included studies. A Hedges’ g effect size (ES) was calculated for indirect markers of EIMD at h post-exercise. Weighted ESs were included in a random effects model to determine overall ESs over time.
Results
Twenty-nine studies were included in the systematic review and 40 trials were included in ≥1 meta-analyses (16 total). There were significant overall effects of protein for preserving isometric maximal voluntary contraction (MVC) at 96 h (0.563 [0.232, 0.894]) and isokinetic MVC at 24 h (0.639 [0.116, 1.162]), 48 h (0.447 [0.104, 0.790]), and 72 h (0.569 [0.136, 1.002]). Overall ESs were large in favour of protein for attenuating creatine kinase concentration at 48 h (0.836 [−0.001, 1.673]) and 72 h (1.335 [0.294, 2.376]). Protein supplementation had no effect on muscle soreness compared with the control.
Conclusion
Peri-exercise protein consumption could help maintain maximal strength and lower creatine kinase concentration following resistance exercise but not reduce muscle soreness. Conflicting data may be due to methodological divergencies between studies. Standardised methods and data reporting for EIMD research are needed.
... However, as the duration, frequency, and volume of resistance training increase, protein supplementation can produce muscle hypertrophy and increase muscle strength. Evidence also shows that protein supplementation provides benefits in increasing aerobic and anaerobic strength (Pasiakos et al., 2014). ...
... There are several research results that discuss the evidence base for the use of protein supplements (McLellan et al., 2013;Pasiakos et al., 2014). The review discusses whether protein supplementation alone or in combination with carbohydrates accelerates glycogen replenishment, thereby increasing repetition of resistance training performance (Pasiakos et al., 2014), as well as the effects of protein supplementation on muscle breakdown and restoration of muscle function and physical performance. ...
... There are several research results that discuss the evidence base for the use of protein supplements (McLellan et al., 2013;Pasiakos et al., 2014). The review discusses whether protein supplementation alone or in combination with carbohydrates accelerates glycogen replenishment, thereby increasing repetition of resistance training performance (Pasiakos et al., 2014), as well as the effects of protein supplementation on muscle breakdown and restoration of muscle function and physical performance. ...
Consumption of protein in weight training when adjusted to the needs will result in perfect muscle growth and development, especially in increasing maximum strength. In fact, many Fitness Members consume protein without paying attention to the dose, so that increasing maximum strength is not realized properly. This study aims to provide high-protein supplements and high-protein foods in weight training to increase maximum muscle strength. The design used in this study is a three group pre test and post test, consisting of a group consuming high protein supplements, a group consuming a high protein diet and a control group. The population in this study are FIK UNP students, with a total sample of 39 people. The instrument used in this study is a maximum strength test (leg & Hand Dynamo Meter test). The data obtained in this study are analyzed by analysis of variance (ANOVA) with = 0.05. The results showed: (1) There was a difference in effect between the group given high protein supplements, high protein die,t and the control group, (2) The group given high protein supplements had a difference from the average of the other two groups, (3) The group given high protein supplements high-protein supplements had a difference from the average of the other two groups, (4) The high-protein diet group did not have a mean difference with the control group. The limitation in this study is that the researcher was not able to control aspects that were outside the research activities such as other high protein contamination consumed by the research food samples. The next stage, this research will look at the effects of consuming high-protein supplements on a sustainable basis on human health.
... Several recovery strategies, including load management (expressed as minutes played per game), compression, cold-water immersion, physiotherapy methods, and nutritional interventions, have been examined in terms of their efficacy in accelerating skeletal muscle and performance recovery during a congested team sports schedule [14,[17][18][19][20]. Nutritional strategies, particularly those focusing on increased carbohydrate, fluid, and protein intake, have been shown to support the recovery process of muscle function and physical performance in team sport athletes [21]. Particular attention has been paid to protein, given its ability to maximize muscle protein synthesis and promote a positive net protein balance during recovery from exercise [22,23]. In addition, most high-quality protein supplements are rich in sulfur-containing amino acids (glycine, glutamate, cysteine), which are precursors for the synthesis of glutathione (GSH) [24], a pivotal antioxidant that regulates cellular redox homeostasis and mitigates the inflammatory and oxidative stress response to EIMT [25,26]. ...
... Protein supplementation failed to elicit any effect on CK and muscle function during the congested schedule. Increased protein intake has been extensively examined as a dietary strategy to facilitate exercise-induced muscle trauma, given its effectiveness in stimulating muscle protein synthesis [22,23]. According to a recent systematic review with meta-analysis, increased peri-exercise protein intake can preserve muscle strength and mitigate the rise of CK concentration in the bloodstream following resistance exerciseinduced muscle trauma [23]. ...
Background/objectives:
Despite being widely promoted, protein supplementation's overall effectiveness during demanding basketball schedules remains unclear. This study investigated whether increased protein intake can accelerate recovery of muscle function during a 6-day congested basketball microcycle consisting of three consecutive games while accounting for the impact of playing time.
Methods:
In a randomized, two-trial, cross-over, double-blind repeated measures design, eighteen male basketball players were assigned to a high (High PT) or a moderate (Mod PT) playing time group and participated in two trials, receiving daily either milk protein (PRO trial) or an isoenergetic amount of carbohydrates. Each trial included three consecutive games (days 1-3) and a 72 h recovery period following Game 3 (days 4-6), during which players participated in low-load practice sessions. Isometric and isokinetic peak torque of knee extensors and flexors in the dominant limb, serum creatine kinase (CK) concentration, and erythrocyte glutathione (GSH) levels were assessed prior to each game and practice session.
Results:
CK increased (p < 0.01) on game days in both groups but recovered earlier in Mod PT compared to High PT. Both eccentric and concentric peak torque was impaired (p < 0.01) up to 24-48 h post-G3 in a velocity-dependent manner. Eccentric peak torque of knee flexors at 60°/s declined to a greater extent in High PT compared to Mod PT (p < 0.01). Protein supplementation resulted in higher erythrocyte GSH concentration at pre-G2 (p < 0.05) and pre-G3 (p < 0.05) compared to placebo in both groups but did not affect any of the study outcomes.
Conclusions:
Increased protein intake during a congested basketball schedule increases erythrocyte GSH concentration but does not accelerate recovery of muscle function.
... The growing global population and rising awareness of protein's role in health have significantly increased protein demand [1][2][3][4]. Plant and animal-based protein sources have been widely used in the food processing industries for their nutritional and functional attributes [5,6]. However, animal-based proteins raise concerns due to their environmental impact and potential health risks. ...
... However, soy protein's processing instability and presence of antinutrients limit its full potential. For instance, when used in the raw state, coating and packaging materials have weak mechanical properties and less moisture resistance [5][6][7]. The modification methods could improve existing properties such as emulsification, foaming, and gas barrier properties of soy proteins or create new protein functionality such as ...
The shift towards sustainability has increased the demand for plant proteins that mimic the functional quality of traditional animal proteins. Soy proteins have an edge over other plant proteins due to their nutritional and functional properties. However, their sensitivity to processing conditions, allergenicity, and poor digestibility hinder their direct applications. The modification strategies improve soy protein functionality and diversify their applications by altering their size, structure, hydrophilicity, and hydrophobicity. The selection of the modification method is highly dependent on the end application of modified soy protein ingredients. Therefore, discussing the interplay between different modification strategies and the functionality of soy protein is particularly needed for suitable industrial applications. In the present study, authors systematically selected 221 eligible published articles and book chapters related to soy proteins out of 5218 for reviewing using the Scopus database between 2013 and 2022. The review results highlighted a growing interest in sustainable packaging using modified soy protein. The ever-increasing industrial interest in areas such as encapsulation, fat replacers, and meat analogues has prompted researchers to focus on modification methods that specifically influence the gelling and emulsification properties of soy protein. Understanding the effect of modification strategies on protein structure and their synergistic interaction is crucial for targeted soy protein functionality. This knowledge can be leveraged to develop innovative and versatile plant-based products that compete effectively with animal-derived counterparts.
... Optimising recovery is important for limiting muscle soreness and restoring muscle strength following resistance exercise. Nutritional interventions, particularly those high in protein, are widely used in younger adults and athletes for exercise recovery [6,7]. A protein-rich whole food that has gained popularity as an exercise recovery aid is cow's milk, which can stimulate muscle protein synthesis to similar levels as whey, alongside having a favourable macro-and micronutrient content that could contribute to exercise recovery [8,9]. ...
... This is similar to the exercise protocol recommended by a meta-analysis seeking the most effective RE protocol for older adults [19], and to the protocol used by the singular recovery intervention study in older adults [20], but used larger muscle groups of the lower limbs and was altered after pilot testing to reflect what researchers thought was attainable using our specific equipment. After each exercise, participants were asked to provide a rating of perceived exertion (RPE) using the Borg (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) scale [21,22], to enable comparison of effort between groups. ...
Maximising the potential benefit of resistance exercise (RE) programs by ensuring optimal recovery is an important aim of exercise prescription. Despite this, research surrounding recovery from RE in older adults is limited and inconsistent. The following randomised controlled trial was designed to investigate the efficacy of milk consumption for improving recovery from RE in older adults. However, the study encountered various challenges that may be applicable to similar studies. These include recruitment issues, a lack of measurable perturbations in muscle function following RE, and potential learning effects amongst participants. Various considerations for exercise research have arisen from the data which could inform the design of future studies in this area. These include (i) recruitment-consider ways in which the study design could be altered to aid recruitment or allow a longer recruitment period; (ii) learning effects and familiarisation-consider potential learning effects of outcome measures and adjust familiarisation accordingly; (iii) identify, validate and optimise protocols for outcome measures that are applicable for the specific population; (iv) adjust the exercise protocol according to the specific aims of the study (e.g., are you replicating a usual exercise bout or is the intent to cause large amounts of muscle damage?).
... Кортизол має багатогранні метаболічні функції, зокрема бере участь у регулюванні рН позаклітинної рідини 43 втрачають дуже багато натрію, це прискорює швидкість виведення калію. Отже, кортизол регулює дію натрієво-калієвих насосів для досягнення іонної рівноваги після будь-якої дестабілізуючої події, включаючи фізичне навантаження 44 . ...
... Хоча наднирковим залозам необхідно секретувати більше кортизолу у відповідь на психологічний або фізичний стрес, також важливо, щоб вміст кортизолу повертався до нормальних значень після стресової події. На жаль, у деяких спортсменів стресова реакція на 44 Hu Y. C., Chu K. інтенсивні навантаження активується так часто, що зміни метаболізму не завжди мають шанс повернутися до нормального стану. Це може призвести до проблем зі здоровʼям, у тому числі, до формування хронічного стресу та розвитку перевтоми й перетренованості. ...
... Interest in post-exercise recovery has drastically increased in the last few decades [4], and nutrition is a key strategy in this process [5,6]. Several dietary and supplementation strategies have been proposed to attenuate symptoms of EIMD [1,7,8]. One of the strategies tested is based on antioxidant supplementation, which targets reactive oxygen and nitrogen species (RONS) as factors involved in EIMD [2,3,9]. ...
... The diet was adjusted to provide 6 g/kg/d two days before the intervention and 7 g/kg/d of carbohydrate from the day before trial, until the end of the trial. Protein intake was adjusted to 1.6 g/kg and distributed in three main meals and two collations [8,28,29]. Foods with high amounts of antioxidants, such as more than four cups of tea or coffee, more than two fruit juices and alcoholic beverages were avoided two days prior to the intervention. During the intervention, coffee and tea were also avoided. ...
Considering the existing controversy over the possible role of acute antioxidant vitamins in reducing exercise-induced muscle damage (EIMD), this doubled-blind, randomized and controlled trial aimed to determine whether supplementation with vitamins C and E could mitigate the EIMD in endurance-trained runners (n = 18). The exercise protocol involved a warm-up followed by 6 to 8 bouts of 1 km running at 75% maximum heart rate (HRmax). Two hours before the exercise protocol, participants took the supplementation with vitamins or placebo, and immediately afterwards, blood lactate, rate of perceived exertion and performance were assessed. At 24 h post-exercise, CK, delayed onset muscle soreness and performance were determined (countermovement jump, squat jump and stiffness test). The elastic index and vertical stiffness were calculated using a stiffness test. Immediately after the exercise protocol, all participants showed improved maximum countermovement jump, which only persisted after 24 h in the vitamin group (p < 0.05). In both groups, squat jump height was significantly greater (p < 0.05) immediately after exercise and returned to baseline values after 24 h. The elastic index increased in the vitamin group (p < 0.05), but not in the placebo group. In both groups, lactate levels increased from pre- to immediately post-exercise (p < 0.05), and CK increased from pre- to 24 h post-exercise (p < 0.05). No significant differences between groups were observed in any of the variables (p > 0.05). Vitamin C and E supplementation does not seem to help with EIMD in endurance-trained individuals.
... Furthermore, continuously carrying a load on one side of the body can lead to muscle fatigue due to increased muscle use on opposite sides since carrying one hand results in high spine compression when bilateral carrying (34). This fatigue phenomenon can affect the consistency of the result and then influence the reliability of this unilateral carrying task (35). Nevertheless, bilateral carrying becomes the most demanding task compared with other carrying on the worksite (36). ...
... Therefore, prolonged physical activity between the tests may lead to fatigue. A previous study stated intensive training of muscles causes a decline in performance (35). For instance, Ahmed (39) suggested avoiding upper extremity fatigue among basketball players since it may reduce grip strength and affect performance. ...
Introduction: Load carriage is one of the most frequent manual material handlings in industrial settings. However, due to the biomechanical risk exposures, carrying could lead to work-related musculoskeletal disorders. Joule’s Functional Capacity Evaluation is an FCE system used widely in Malaysia in return-to-work programs to ensure work readiness and prevent re-injury. However, the literature regarding the test-retest reliability of the carrying protocols is minimal, leading to a questionable level of consistency. Therefore, this study aimed to investigate the test-retest reliability of the carrying protocols in Joule’s FCE. Methods: A cross-sectional study was conducted to evaluate test-retest reliability where the carrying protocol of Joule’s Functional Capacity Evaluation was used among healthy university students (N=30). The participants were asked to perform a retest of the carrying protocol after one week.Results: The ICC values for the carrying protocols were good for dominant unilateral carrying was (ICC: 0.82; 95% CI: -6.00 to 5.81), non-dominant carrying was (ICC: 0.74; 95% CI: -6.78 to 6.02) and bilateral carrying was (ICC: 0.85; 95% CI: -6.26 to 5.51). Bland and Altman’s plot indicated no visible distribution patterns of the differences without exceeding the 95% limits of agreement. The standard error of measurements (SEMs) was relatively small for all carrying protocols. Conclusion: The test-retest reliability of carrying protocols in Joule’s FCE was good. Future studies are needed to replicate this study in real patients to further verify the reliability for clinical settings.
... Whey proteins are one of the most important and primarily used proteins, found in dairy products which are extracted from milk whey, liquid material which is manufactured as a byproduct in cheese making process. Bioactive peptides are one of the most studied compounds in milk whey, which performs various biological roles 10,11 .Whey milk proteins contain essential amino acids in bulks which carry out functions that proteins perform in the body and are used in manufacturing products like, foods for the infant, nutritional products most probably applied for athletes, products used somehow to control obesity, mood control and other vital protein supplements for treating enteric disturbances. In addition, fermented dairy products (e.g. ...
... In addition, fermented dairy products (e.g. yoghurt and cheese) are gaining more popularity as they are considered to be a good source of dairy peptides and also reduce the risk of hypertension and coagulopathy and cancer [10][11][12][13][14] . ...
Whey protein is one of the major sources of essential proteins which is being used widely now days for
maintaining a healthy life style and to meet the daily protein requirement. In order to maintain a healthy body
weight, regular exercise accompanied with a healthy diet is very important, and whey protein is a perfect source
of fulfilling the protein requirements of the body. Whey is obtained majorly from milk which is formed by the
production of cheese. Milk is the major source of whey as it comprises 20% of the total constituent of milk.
Whey protein is a high-quality protein with a rich amino acid profile. It contains the broad spectrum of amino
acids that includes essential amino acids (EAAs) and branched-chain amino acids (BCAAs) which are important
in the growth and repair of tissues. Leucine, Isoleucine and Valine are the amino acids that play a major role in
BCAA in protein synthesis and has recently been identified as playing role in muscle building and increase in the
hormonal growth. It is easy to digest as compared to other components of milk like casein and has no fat content
in it which makes it possible to help in gaining lean muscle mass in the body. These are one of the many
advantages of consuming whey for which its demand in the market is rising. Despite numerous advantages it
can show some side effects like kidney problems, indigestion, bloating, etc. So it is advisable to consume it after
consulting with a physician or some health expert in a specific dosage for a period of time. This review article
gives a brief explanation of the role of whey proteins present in milk.
... 22,23 Protein supplements are used by athletes to promote skeletal muscle anabolism and enhance recovery of muscle function and regeneration. 24,25 Anti-inflammatory supplements are used to reduce inflammation related to skeletal muscle damage, 26 whereas antioxidants have received interest as a useful tool in preventing or reducing OS and decreasing muscle damage. [27][28][29] Amongst dietary supplements, spirulina (Arthrospira) is widely used by athletes. ...
... 56 Athletes need to ingest sufficient high-quality protein to maintain essential amino acid availability, 57 reduce skeletal muscle damage 58,59 and enhance recovery. 24 Spirulina's composition is interesting for this population because, in addition to amino acids, it contains many compounds with antioxidant and antiinflammatory virtues favourable to the process of muscle regeneration and skeletal muscle damage reduction. 60 To the best of our knowledge, the present study is the first to use the YYIRT-2 as an exhaustive exercise to induce OS, inflammation and skeletal muscle damage. ...
Objective:
This study aimed to examine the effects of spirulina supplementation on pro/antioxidant status, inflammation, and skeletal muscle damage markers immediately and 24h after exhaustive exercise in elite rugby players.
Methods:
Seventeen elite male Rugby Union players were randomly assigned to a Spirulina (SPI: n=9), or a placebo group (PLA: n=8) in a double-blind design. Subjects were supplemented with Spirulina platensis (5.7 g/d) or placebo (isoproteic and caloric) for 7 weeks. At baseline (W0) and after seven weeks of supplementation (W7), blood samples were obtained before (T0), immediately after (T1), and 24h after (T2) exhaustive exercise. The Yoyo Intermittent Recovery Test Level 2 was used as an exhaustive exercise to induce oxidative stress (OS), inflammation, and skeletal muscle damage. The studied parameters included Pro/antioxidant status markers (SOD, GPX, GSH/GSSG ratio, ox-LDL, and F2-Isop), inflammation markers (MPO and CRP), and skeletal muscle damage markers (LDH and CK).
Results:
Our results showed that F2-Isop, CRP, and CK levels significantly increased at T1 only in PLA group (p<0.05, p<0.05, and p<0.001 respectively) with no change in SPI group which reflects the effect of spirulina to prevent lipid peroxidation, inflammation, and skeletal muscle damage induced by exhaustive exercise. Moreover, spirulina supplementation accelerated the return to baseline values given that F2-Isop, CRP, and CK levels at T2 were significantly lower than at T0 in SPI group (p<0.05, p<0.01, and p<0.001 respectively).
Conclusion:
Based on the markers used in this study, our results report that spirulina supplementation potentially prevents exercise-induced lipid peroxidation, inflammation, skeletal muscle damage and may accelerate the recovery of some of these markers. Based on our findings, we recommend spirulina supplementation especially for athletes who do not achieve the recommended antioxidant dietary intake and who perform a high training load in order to reduce the magnitude of OS, inflammation, and skeletal muscle damage which could help to reduce performance losses and accelerate recovery after training/competitions throughout the season. This article is protected by copyright. All rights reserved.
... Resistance exercise (RE), particularly eccentric muscle contractions, produces mechanical damage that can be indirectly measured through different variables such as loss of repetition maximum (RM), the delayed onset of muscle soreness (DOMS), which encompasses diminished post-exercise muscle strength, swelling, perceived pain, and restricted range of motion [8], and plasma biomarkers of inflammation and stress including, interleukin-1, interleukin-6, and tumor necrosis factor-alpha [9]. The amount of lactate, lactate dehydrogenase (LDH), and creatine kinase (CK) in blood are also closely associated with muscle cell disruption and are important indicators of exercise-induced damage [8,10]. ...
Leucine is an essential branched-chain amino acid required for skeletal muscle protein synthesis as a substrate and as a key anabolic signaling molecule primarily via activation of the mTORC1. Leucine supplementation has been proposed to enhance muscle adaptations, with some studies showing improvements in muscle growth. However, results from randomized controlled trials (RCTs) have been inconclusive, potentially due to variations in resistance exercise protocols and Leu dose or duration of supplementation. This systematic review explores the effects of leucine supplementation on resistance-training-induced muscle growth, strength, and recovery in healthy individuals.
A systematic literature search was conducted across multiple databases (MedLine, EMBASE, PubMed, Science Direct, Scopus, and Cochrane) to identify RCTs investigating the effect of leucine intake on markers of muscle growth, strength, and recovery in trained adults aged 18 to 40 years old.
A total of 14 RCTs were identified including acute (n = 5) and chronic leucine (n = 9) supplementation. A total of 13 studies did not find significant differences in muscle mass, strength, or recovery between leucine-supplemented and placebo groups.
The evidence from this systematic review suggests that leucine supplementation does not confer significant benefits in muscle growth, strength, or recovery in healthy, trained young adults.
... Routine intake of dietary protein directly affects skeletal muscle protein turnover, promotes muscle damage repair, and improves physical activity performance [33,34]. High concentrations of amino acids have a direct effect on the rate of muscle synthesis, with one regression study showing that Page 10 of 12 a 100% increase in peripheral EAA concentration resulted in an increase in muscle protein of approximately 34% [35]. ...
Background
With the acceleration of aging, sarcopenia has become a reality of concern today. This study aimed to evaluate the efficacy of various non-pharmacologic interventions and find the optimal interventions for sarcopenia.
Methods
PubMed, Medline OVID, EMBASE, Scopus, and Cochrane were searched from 1 January 2000 to 25 October 2023, with language restrictions to English. We analyzed the data through the Bayesian network meta-analysis.
Results
Based on the inclusion and exclusion criteria defined by the PICOS principles, we identified 47 eligible clinical trials engaging 4889 individuals (including treatment group = 2835, control group = 2054). The results showed that resistance exercise (low-moderate load) significantly increased muscle mass (skeletal muscle mass and lean body mass) and that exercise plus nutrition improved physical activity indices (handgrip strength, gait speed, TUG test, chair standing).
Conclusion
Resistance exercise (low-moderate load), exercise plus nutrition, and nutritional supplementation (fatty acids, etc.) may be protective against sarcopenia.
Systematic Review Registrationhttps://www.crd.york.ac.uk/prospero/display_record.php?RecordID=474799, ID: CRD4202347479.
... However, this was not a given as the results of previous studies are inconsistent [9,30,32,33,57]. The disparate findings may in part be due to the various issues that plague many protein intervention studies [67]. These include, but are not limited to, different modes of exercise used to induce, and criteria used to assess, EIMD; dosing, timing, and duration of interventions; participant training history; choice of control/placebo [9,38,39,42]; insufficient levels of damage; studies being under powered [18,30,66]; and, perhaps most importantly [65], a lack of control over dietary protein intake [10,[15][16][17]36,38,41,64]. ...
Background: Consuming collagen hydrolysate (CH) may improve symptoms of exercise-induced muscle damage (EIMD); however, its acute effects have not been compared to dairy protein (DP), the most commonly consumed form of protein supplement. Therefore, this study compared the effects of CH and DP on recovery from EIMD. Methods: Thirty-three males consumed either CH (n = 11) or DP (n = 11), containing 25 g of protein, or an isoenergetic placebo (n = 11) immediately post-exercise and once daily for three days. Indices of EIMD were measured before and 30 min and 24, 48, and 72 h after 30 min of downhill running on a −15% slope at 80% of VO2max speed. Results: Downhill running induced significant EIMD, with time effects (all p < 0.001) for the delayed onset of muscle soreness (visual analogue scale), countermovement jump height, isometric midthigh pull force, maximal voluntary isometric contraction force, running economy, and biomarkers of muscle damage (creatine kinase) and inflammation (interleukin-6, high-sensitivity C-reactive protein). However, no group or interaction effects (all p > 0.05) were observed for any of the outcome measures. Conclusions: These findings suggest that the post-exercise consumption of CH or DP does not improve indices of EIMD during the acute recovery period in recreationally active males.
... In the repair process after skeletal muscle injury, protein synthesis needs to be greater than catabolism to effectively complete the repair process (Pasiakos et al. 2014). The Akt/mTOR signaling pathway is a major signaling pathway for protein synthesis, and the repair process after skeletal muscle injury may be accelerated by activating Akt/mTOR and its downstream signaling molecules to promote protein synthesis (Perry et al. 2016). ...
High-intensity exercise can cause excessive generation of ROS and induce oxidative stress injury in the body, which is a major reason accounting for muscle damage following exercise. The previous study demonstrated that IBS008738, the activator of TZA, was able to enhance myogenesis in mouse myogenic C2C12 cells, prevent dexamethasone-induced muscle atrophy, and facilitate muscle repair in cardiotoxin-induced muscle injury. Accordingly, our study was designed to probe into the potential role of IBS008738 in muscle damage in mouse models induced by high-intensity exercise. Mice were first administrated with IBS008738, and then subjected to high-intensity eccentric exercise to induce muscle damage after 24 h. During the experiment, mouse weight change and food take were recorded. At the end of the experiment, blood samples were collected through cardiac puncture and centrifugated. Serum levels of blood urea nitrogen (BUN), creatinine, glucose, lactate dehydrogenase (LDH), creatinine kinase (CK), and C-related protein were evaluated using an autoanalyzer. After mice were sacrificed, the gastrocnemius muscles were dissected for DCFH-DA assay of ROS generation, thiobarbituric acid-reactive substances (TBARS) assay of MDA content, hematoxylin‐eosin (H&E) staining of histological examination, and western blotting analysis of Akt/mTOR/S6K1 signaling expression. IBS008738 and/or exercise exert significant effects on mouse weight and food take. High-intensity exercise markedly increased ROS generation and lipid peroxidation, upregulated serum levels of CK, LDH, and C-related protein, ameliorated muscle histological damage, and reduced TAZ, phosphorylated (p)-Akt, p-mTOR, and p-S6K1 protein levels in mice. However, IBS008738 administration reversed the above changes induced by high-intensity exercise in mice. IBS008738 alleviates oxidative stress and muscle damage in mice after high-intensity exercise by activating TAZ and the Akt/mTOR/S6K1 signaling pathway.
... It is noteworthy that the literature already partially supports physical and manual treatments that appear to mitigate delayed onset muscle soreness, as well as supplemental sources rich in proteins [19][20][21]. However, the focus of this review is on supplementation, without excluding manual interventions. ...
Background/objectives: The oral administration of hydrolyzed collagen peptides is a scientifically validated intervention for enhancing skeletal muscle health and performance. This integrative review consolidates the evidence supporting the use of low molecular weight collagen peptides (2000–3500 daltons) for their superior bioavailability and absorption. Our objective was to review the effects of collagen peptide or hydrolyzed collagen supplementation on muscle damage, recovery, and construction related to physical exercise. Methods: A bibliographic search was conducted in major English-language databases, including PubMed/Medline, using terms like “Peptides Collagen and Damage” and “collagen peptides AND Soreness Muscle”. This review followed PRISMA guidelines, with bias risk assessed via the PEDro scale. The inclusion criteria were (a) randomized clinical trials, (b) randomized studies in humans with a control or placebo group, (c) studies assessing muscle damage or delayed onset muscle soreness via physiological markers or strength performance tests, and (d) studies using hydrolyzed collagen or collagen peptides. Results: Initially, 752 articles were identified. After applying the inclusion and exclusion criteria, including duplicate removal, eight articles with 286 participants were included. Of these, 130 participants received collagen peptide supplementation, while 171 received a placebo or control. Conclusion: This integrative review supports the potential of collagen peptide supplementation to mitigate muscle stress from acute strenuous resistance training. However, due to the methodological heterogeneity among the studies, further clinical trials are needed to clarify the mechanisms underlying muscle improvement with collagen supplementation.
... Badminton belongs to the sports disciplines that require players to move quickly towards the projectile. Therefore, badminton athletes must avoid harmful factors, one of them being muscle damage [13]. It consists in muscles becoming stiff or sore, is caused by strenuous physical exercise, and becomes apparent within 24-72 hours after exercise [14]. ...
... Concerning recovery from exercise, the ingestion of protein supplements can enhance skeletal muscle protein synthesis by stimulating a greater ratio of myofibrils to mitochondria (96). Despite the fact that athletes require extra protein being widely proven, the majority of athletes already consume a balanced diet that covers their protein needs (97). ...
Information regarding the dietary requirements and consumption of young athletes is limited. Hence, the aim of this narrative review is to provide a comprehensive combination of research and review papers on the nutritional status of young athletes aged 5–18 years old, as well as quantitative, qualitative, wholesome foods, food choices, and eating disordered data concerning the dietary requirements for growing young athletes. This study involved systematic searches of electronic databases, including Google Scholar, PubMed, Science Direct, Scopus, and Web of Science. The specific criteria for identifying research papers published in English from July 1980 until May 2024 were included. Only 48 studies out of 1,262 were included in this narrative review. The findings of this study suggest that, compared with adults, junior athletes need a unique approach to meet their dietary needs. Growth, development, and general athletic performance depend on macronutrients, as they are vital nutrients for young active athletes. However, research on enhancing junior athletes’ performance is still in progress, and studies on hydration status, and eating disorders are limited.
... Second, both endurance training (especially highintensity training such as HIIT) and resistance training can cause exercise-induced muscle micro-trauma. Post-exercise protein supplementation provides the necessary substrates for muscle repair and promotes faster recovery [98]. This accelerated recovery allows for more effective subsequent training sessions, enhancing overall training adaptations. ...
Combined endurance and resistance training, also known as “concurrent training”, is a common practice in exercise routines. While concurrent training offers the benefit of targeting both cardiovascular and muscular fitness, it imposes greater physiological demands on the body compared to performing each modality in isolation. Increased protein consumption has been suggested to support adaptations to concurrent training. However, the impact of protein supplementation on responses to low-volume concurrent training is still unclear. Forty-four untrained, healthy individuals (27 ± 6 years) performed two sessions/week of low-volume high-intensity interval training on cycle ergometers followed by five machine-based resistance training exercises for 8 weeks. Volunteers randomly received (double-blinded) 40 g of whey-based protein (PRO group) or an isocaloric placebo (maltodextrin, PLA group) after each session. Maximal oxygen consumption (VO2max) and overall fitness scores (computed from volunteers’ VO2max and one-repetition maximum scores, 1-RM) significantly increased in both groups. The PRO group showed significantly improved 1-RM in all major muscle groups, while the PLA group only improved 1-RM in chest and upper back muscles. Improvements in 1-RM in leg muscles were significantly greater in the PRO group versus the PLA group. In conclusion, our results indicate that adaptations to low-volume concurrent training, particularly leg muscle strength, can be improved with targeted post-exercise protein supplementation in untrained healthy individuals.
... Regardless of supplementation status, these data imply that the water polo players' rigorous daily training schedule was a significant contributor to muscle stress. Our findings are similar to earlier studies on the effects of high-intensity sports on muscle injury, which have repeatedly demonstrated that dietary interventions, while maybe helpful, fall short of completely mitigating the damage that exercise causes to muscles [30,31]. ...
Background: A common tactic used by athletes to improve performance, lessen tiredness, and hasten recovery is dietary supplementation. We aimed to assess the role of a microalgae dietary liquid supplement additivated with Copper 22.5% NRV in water polo players’ performance. Methods: Twenty male water polo players were split into two groups: ten (spirulina group) took a twice-daily nutritional supplement containing 15 mL of spirulina liquid extract (titrated in Phycocyanin 1 mg/mL) and additivated with Copper 22.5% NRV for eight weeks, and ten (the placebo group) did not take the supplement. Subjective evaluations were finished using the Athlete’s Subjective Performance Scale (ASPS). Levels of the biomarker creatine phosphokinase (CPK) were also assessed. Results: The spirulina group’s mean total ASPS score increased significantly from baseline to follow-up and was significantly better than that of the placebo group (p < 0.001). Conversely, ASPS ratings in the placebo group slightly decreased. A positive correlation between spirulina supplementation and less severe ASPS was found using correlation matrix analysis. However, there was a slight difference in CPK levels from the baseline to the follow-up in the spirulina group. Conclusions: A dietary supplement comprising spirulina and copper may help water polo players’ subjective performance measurements by lowering muscular tension. Larger, randomized controlled trials are yet required.
... 25 In a 2014 review, the authors state that the physical performance test in clinical research usually involves cycling or running to exhaustion at a given exercise intensity or over a set distance and timed to completion. 16 Muscle function tests include isometric, isokinetic, or dynamic measures of muscle strength, like one-repetition maximum (1RM), or muscular endurance measured by repetitions performed over a defined range of motion and resistance. The dips exercise in our study showed a 30% improvement for the EAA group between day 1 and 3 over exercise. ...
Introduction: Prior studies of the acute benefits of protein supplementation have determined a benefit in improving post-exercise muscle anabolism and aiding the recovery of muscle function and performance. Previous acute protein supplement studies in post-exercise protein synthesis and anabolic intracellular signaling reported no attenuation in muscle damage or elevated muscle function. The aim of this study is to implement a specific content of essential amino acids with resistance and aerobic exercises to quantify the difference in strength, endurance, and flexibility during the delayed onset muscle soreness common with a new exercise protocol. Methods: We enrolled 42 participants (22 EAA and 20 Controls) completed an hour-long aerobic and resistance exercise protocol including flexibility, resistance, and aerobic exercises for three consecutive days. The study participants were randomly assigned to the EAA (6.6g) per day (EAA + Gatorade) group or the control (Gatorade) group. The data was analyzed in a double-blinded format. Results: Both groups improved the initial flexibility respectively throughout the three exercise days but were not significantly different (p=0.32) in the sit and reach. For the resistance/power activities, the EAA group improved in the repetitions for push-ups (p=0.014 vs 0.21) and dips (0.0002 vs 0.59) compared to the controls. The EAA group was faster although not statistically significant in the 20-meter sprint and improved in the 1.5-mile run during the third day (P=0.002 vs 0.48) compared to the control group. Conclusions: The data in the results supports that acute ingestion of the essential amino acid supplements provides increased physical performance and decreases the DOMS symptoms in sedentary participants over the three-day trial period of exercise.
... Daily protein supplementation is associated with increased protein synthesis, [25][26][27][28][29][30][31] which may be related to reduced fatigue and soreness, 32 and a potential increase in satiety hormones and amino acids. 33 Previous studies have reported increased protein synthesis and the attenuated decline in postprandial protein synthesis with just two weeks of protein supplementation. ...
Introduction: Benefits of protein consumption are established, yet athletes often consume insufficient protein. The effect of protein supplementation timing on self- reported wellness measures (SRWM) is unknown. The purpose was to examine the effect of protein supplementation timing on overall protein intake and SRWM. Methods: Collegiate athletes (men: n=13; body mass: 76.1 ± 6.6 kg; body fat %: 14.8 ± 2.3%) (women: n=16; body mass: 72.5 ± 10.8 kg; body fat %: 24.9 ± 4.6%), defined as protein-insufficient (daily intake <1.5 g/kg body weight) participated. Protein supplementation occurred over two 2-week periods (morning, evening) separated by a 2-week washout. Daily SRWM (fatigue, soreness, sleep, stress, mood, energy, recovery, satiety) were collected. ANOVA assessed differences in total protein intake and SRWM measures across conditions. Spearman correlations assessed relationships between protein intake and SRWM.Results: No sex difference existed in protein intake based on supplementation timing. Compared to baseline, morning and evening supplementation led to an increase (p<0.05) in absolute and relative protein intake for men and women. Satiety was increased during morning and evening conditions compared to washout for men (p=0.004) and women (p=0.012), but other SRWM did not differ. Correlations existed for relative protein intake and satiety (r=0.499, p<0.001) and stress (r=-0.321, p=0.019).Conclusions: Protein supplementation enabled participants to achieve the recommended protein intake and provided a greater feeling of satiety. Satiety did not differ between morning and evening, providing flexibility as to when to ingest a daily supplement.
... Protein supplements have become a common part of modern diets, offering a practical and effective way for individuals to meet their daily protein requirements. This aspect is critically essential for populations such as athletes, people engaged in physically demanding jobs, and individuals with specific dietary preferences who rely on protein supplements to aid in muscle development, enhance post-workout recovery, and support overall health [1]. Protein supplements have been derived from both animal and plant sources. ...
The study aimed to determine the phenolic content and antioxidant capacity of five protein supplements of plant origin. The content and profile of phenolics were determined using the UHPLC-DAD-MS method, while antioxidant capacity (ABTS and DPPH assays) and total phenolic content (TPC) were evaluated using spectrophotometric tests. In the analyzed proteins, twenty-five polyphenols were detected, including eleven phenolic acids, thirteen flavonoids, and one ellagitannin. Hemp protein revealed the highest individual phenolics content and TPC value (1620 μg/g and 1.79 mg GAE/g, respectively). Also, hemp protein showed the highest antioxidant activity determined via ABTS (9.37 μmol TE/g) and DPPH (9.01 μmol TE/g) assays. The contents of p-coumaric acid, m-coumaric acid, kaempferol, rutin, isorhamnetin-3-O-rutinoside, kaempferol-3-O-rutinoside, and TPC value were significantly correlated with antioxidant activity assays. Our findings indicate that plant-based protein supplements are a valuable source of phenols and can also be used in research related to precision medicine, nutrigenetics, and nutrigenomics. This will benefit future health promotion and personalized nutrition in the prevention of chronic diseases.
... Enerji kısıtlaması veya kilo kaybı dönemlerinde, fiziksel aktivite de dahil olmak üzere protein alımı, kas kütlesini korumak için hayati önem taşır (Pasiakos, Lieberman & McLellan, 2014). Egzersizle birlikte daha yüksek derecede protein alımı, kas kaybını azaltmaya ve metabolik hızı korumaya yardımcı olur (Helms ve ark., 2014). ...
... Studies show that though high protein intake or supplementing diet with whey protein may not prevent DOMS, it can facilitate recovery and post-exercise anabolism. [11] Another more efficient way to overcome DOMS could be increasing intake of specific amino acids like branched-chain amino acids (BCAAs). A study by Weber et al. found that the use of BCAAs, even after a single bout of strenuous exercise, is helpful. ...
Delayed Onset Muscle Soreness (DOMS) is a prevalent issue in sports medicine and among physically active individuals, causing significant pain and disability. While the exact pathophysiology of DOMS remains incompletely understood, this article delves into non-pharmacological approaches to effectively manage and alleviate its symptoms. The research discusses multifaceted aspects of DOMS, encompassing its complex etiology, theories, and contributing factors. Numerous theories have been proposed, including delayed inflammatory responses, lactic acid accumulation, muscle spasms, connective tissue damage, and muscle micro-tears. These theories underscore the intricate nature of DOMS and the need for a diverse management approach. The article explores non-pharmacological strategies to address DOMS, focusing on evidence-based methods. These methods include massage, exercise, nutrition, and natural supplements. Research has shown that massage therapy enhances muscle recovery, exercise therapy reduces soreness, and nutrition therapy through protein and amino acid intake can alleviate DOMS. Furthermore, natural supplements like ginger, tart cherry juice, and curcumin have demonstrated the potential to reduce inflammation and manage DOMS. While pharmacological interventions may be considered for severe cases, the article underscores the importance of exercising caution due to potential side effects. In summary, DOMS management necessitates a holistic approach, combining multiple modalities and nutritional strategies to alleviate pain, enhance muscle recovery, and minimize the impact of this common condition on physically active individuals and athletes.
... The ability to generate force decreases markedly after exerciseinduced muscle damage, which persists for up to 7 days (15). In addition to physical treatments (10), nutritional supplementation with various protein sources has been linked to a small association between muscle function recovery, muscle soreness, and indirect markers of muscle damage (16). Recently, CP administration has resulted in significant improvements in handgrip strength (17) and isokinetic quadriceps strength (18), producing similar results to whey protein (19). ...
Introduction
It has been shown that short-term ingestion of collagen peptides improves markers related to muscular recovery following exercise-induced muscle damage. The objective of the present study was to investigate whether and to what extent a longer-term specific collagen peptide (SCP) supplementation combined with a training intervention influences recovery markers following eccentric exercise-induced muscle damage.
Methods
Fifty-five predominantly sedentary male participants were assigned to consume either 15 g SCP or placebo (PLA) and engage in a concurrent training (CT) intervention (30 min each of resistance and endurance training, 3x/week) for 12 weeks. Before (T1) and after the intervention (T2), eccentric muscle damage was induced by 150 drop jumps. Measurements of maximum voluntary contraction (MVC), rate of force development (RFD), peak RFD, countermovement jump height (CMJ), and muscle soreness (MS) were determined pre-exercise, immediately after exercise, and 24 and 48 h post-exercise. In addition, body composition, including fat mass (FM), fat-free mass (FFM), body cell mass (BCM) and extracellular mass (ECM) were determined at rest both before and after the 12-week intervention period.
Results
Three-way mixed ANOVA showed significant interaction effects in favor of the SCP group. MVC ( p = 0.02, ηp ² = 0.11), RFD ( p < 0.01, ηp ² = 0.18), peak RFD ( p < 0.01, ηp ² = 0.15), and CMJ height ( p = 0.046, ηp ² = 0.06) recovered significantly faster in the SCP group. No effects were found for muscle soreness ( p = 0.66) and body composition (FM: p = 0.41, FFM: p = 0.56, BCM: p = 0.79, ECM: p = 0.58).
Conclusion
In summary, the results show that combining specific collagen peptide supplementation (SCP) and concurrent training (CT) over a 12-week period significantly improved markers reflecting recovery, specifically in maximal, explosive, and reactive strength. It is hypothesized that prolonged intake of collagen peptides may support muscular adaptations by facilitating remodeling of the extracellular matrix. This, in turn, could enhance the generation of explosive force.
Clinical trial registration
ClinicalTrials.gov , identifier ID: NCT05220371.
... Finally, protein supplementation was administered to participants in the evening prior to sleep, which has been shown to increase total daily protein intake, support MPS through the night and training outcomes (12, 41,43). However, consuming protein during the acute post-exercise period may have more favourable effects on muscle anabolism and outcomes (66). As this study focused on the chronic effects of protein supplementation over 12 weeks of BT, future research may want to consider the impact of protein feeding on physiological adaptations around acute military training activities. ...
Dietary protein is crucial for optimising physical training adaptations such as muscular strength and mass, which are key aims for athletic populations, including British Army recruits. New recruits fail to meet the recommended protein intake during basic training (BT), with negligible amounts consumed in the evening. This study assessed the influence of a daily bolus of protein prior to sleep on performance adaptations, body composition and recovery in British Army recruits. 99 men and 23 women [mean ± standard deviation (SD): age: 21.3 ± 3.5 years, height: 174.8 ± 8.4 cm, body mass 75.4 ± 12.2 kg] were randomised into a dietary control (CON), carbohydrate placebo (PLA), moderate (20 g) protein (MOD) or high (60 g) protein (HIGH) supplementation group. Supplements were isocaloric and were consumed on weekday evenings between 2000 and 2100 for 12 weeks during BT. Performance tests (mid-thigh pull, medicine ball throw, 2 km run time, maximal push-up, and maximal vertical jump) and body composition were assessed at the start and end of BT. Dietary intake, energy expenditure, salivary hormones, urinary nitrogen balance, perceived muscle soreness, rating of perceived exertion, mood, and fatigue were assessed at the start, middle and end of BT. Protein supplementation increased protein intake in HIGH (2.16 ± 0.50 g⸱kg⁻¹⸱day⁻¹) and MOD (1.71 ± 0.48 g⸱kg⁻¹⸱day⁻¹) compared to CON (1.17 ± 0.24 g⸱kg⁻¹⸱day⁻¹) and PLA (1.31 ± 0.29 g⸱kg⁻¹⸱day⁻¹; p < 0.001). Despite this, there was no impact of supplementation on mid-thigh pull performance (CON = 7 ± 19%, PLA = 7 ± 19%, MOD = 0 ± 16%, and HIGH = 4 ± 14%; p = 0.554) or any other performance measures (p > 0.05). Fat-free mass changes were also similar between groups (CON = 4 ± 3%, PLA = 4 ± 4%, MOD = 3 ± 3%, HIGH = 5 ± 4%, p = 0.959). There was no impact of protein supplementation on any other body composition or recovery measure. We conclude no benefits of pre-bed protein supplementation to improve performance, body composition and recovery during BT. It is possible the training stimulus was great enough, limiting the impact of protein supplementation. However, the high degree of inter-participant variability suggests an individualised use of protein supplementation should be explored, particularly in those who consume sub-optimal (<1.6 g⸱kg⁻¹⸱day⁻¹) habitual amounts of protein.
Clinical trial registration: The study was registered with ClinicalTrials.gov, U.S. national institutes (identifier: NCT05998590).
... Generally, it is recognized that 8-10 g (1.8-2.0 g leucine) of essential amino acids maximizes MPS with whey protein specifically leading to a rapid rise in blood amino acid concentrations and therefore MPS (43,44). Nonetheless, it is generally recognized that the total daily intake of protein and wholebody protein balance (i.e., nitrogen balance) are key determinants compared to the timing of protein intake in the context of muscle recovery (45). In the context of this study, the data suggests consuming additional calories, either in the form of CHO or protein attenuated EIMD (Figure 1). ...
British Army basic training (BT) is physically demanding with new recruits completing multiple bouts of physical activity each day with limited recovery. Load carriage is one of the most physically demanding BT activities and has been shown to induce acute exercise-induced muscle damage (EIMD) and impair muscle function. Protein supplementation can accelerate muscle recovery by attenuating EIMD and muscle function loss. This study investigated the impact of an additional daily bolus of protein prior to sleep throughout training on acute muscle recovery following a load carriage test in British Army recruits. Ninety nine men and 23 women (mean ± SD: age: 21.3 ± 3.5 yrs., height: 174.8 ± 8.4 cm, body mass 75.4 ± 12.2 kg) were randomized to dietary control (CON), carbohydrate placebo (PLA), moderate (20 g; MOD) or high (60 g; HIGH) protein supplementation. Muscle function (maximal jump height), perceived muscle soreness and urinary markers of muscle damage were assessed before (PRE), immediately post (POST), 24-h post (24 h-POST) and 40-h post (40 h-POST) a load carriage test. There was no impact of supplementation on muscle function at POST (p = 0.752) or 40 h-POST (p = 0.989) load carriage but jump height was greater in PLA compared to HIGH at 24 h-POST (p = 0.037). There was no impact of protein supplementation on muscle soreness POST (p = 0.605), 24 h-POST (p = 0.182) or 40 h-POST (p = 0.333). All groups had increased concentrations of urinary myoglobin and 3-methylhistidine, but there was no statistical difference between groups at any timepoint (p > 0.05). We conclude that pre-sleep protein supplementation does not accelerate acute muscle recovery following load carriage in British Army recruits during basic training. The data suggests that consuming additional energy in the form of CHO or protein was beneficial at attenuating EIMD, although it is acknowledged there were no statistical differences between groups. Although EIMD did occur as indicated by elevated urinary muscle damage markers, it is likely that the load carriage test was not arduous enough to reduce muscle function, limiting the impact of protein supplementation. Practically, protein supplementation above protein intakes of 1.2 g⸱kg⁻¹⸱day⁻¹ following load carriage over similar distances (4 km) and carrying similar loads (15–20 kg) does not appear to be warranted.
... The factors associated with protein timing and the quality of protein used are equally relevant to assessing the effects of dietary protein intake during long-lasting exercise participation [9]. Therefore, a large number of meta-analyses and experimental and observational studies without intervention have been conducted to summarize the effects of the consumption of protein supplements on the occurrence of changes in body composition, muscular power and strength or the levels of bodily adaptation to exercise [10][11][12][13][14][15][16][17][18][19][20]. ...
Athletes need to develop a relatively high muscle mass and low body adipose tissue for the sake of better athletic performance. A full range of nine essential amino acids and eleven non-essential amino acids have to attend in appropriate amounts for protein biosynthesis. The aim of the observational comparative cross-sectional study was to assess the association between the diet quality profile and training-induced muscle mass estimated by bioelectrical impedance among elite male athletes. The research sample comprised 18.1 ± 3.1 year-old Lithuanian professional male athletes (n = 234). The study participants were enrolled to complete 24-h dietary recalls of three non-consecutive days. The body composition was assessed using the bioelectrical impedance analysis (BIA) method. The present study showed a significant insufficiency of the mean carbohydrate intake of 5.7 g/kg/day in a group of aerobic male athletes. The lower muscle mass of aerobic male athletes was related to the lower-carbohydrate diet (adjusted odd ratio (ORadj) 0.3; 95% confidence interval (CI): 0.1–0.7). The mean protein intake of 1.8 g/kg/day was optimal for anabolism in the samples of both anaerobic and aerobic male athletes. The protein intake in appropriate doses was potentially associated with an increase in muscle mass only in anaerobic male athletes (ORadj 2.2; 95% CI: 1.3–3.7). The positive relationship was revealed between the possible muscle mass gain and the increased intakes of amino acids such as isoleucine and histidine among anaerobic athletes (ORadj 2.9; 95% CI: 1.1–4.7 and ORadj 2.9; 95% CI: 1.0–4.3, respectively). An inverse feasible association was indicated between a higher intake of valine and lower muscle mass quantities among anaerobic male athletes (ORadj 0.1; 95% CI: 0.1–0.5). The recommendations for sports nutritionists should emphasize the necessity of advising professional athletes on dietary strategies on how to manipulate dietary amino acid composition with respect to achieving long-term body composition goals.
... In addition, it is also important to pay attention to protein intake from daily food so as not to exceed the body's needs. The recommended dosage for the use of protein supplements varies depending on the type of protein, the purpose of use, and the individual condition, in general, consumption of 0.25-0.3grams of protein per kilogram of body weight every 3-4 hours can help maximize muscle protein synthesis, in addition, it is important to pay attention to protein intake from the daily diet to avoid excess protein that can harm kidney and heart health [26]. ...
Athletes widely use nutritional supplements to increase muscle strength and endurance. This review aims to summarize the effects of commonly used dietary supplements on muscle strength and endurance in athletes. A literature search identified several dietary supplements studied for their impact on muscle performance, including protein supplements, creatine, beta-alanine, branched-chain amino acids (BCAAs), caffeine, nitrates, and vitamins and minerals. The review discussed the mechanisms by which this supplement affects muscle strength and endurance. The review methodology includes a systematic literature search, study selection, and data analysis. The review summarizes the effects of each type of supplement on muscle strength and endurance based on the available literature. The discussion includes an overview of the effectiveness and safety of using nutritional supplements to increase muscle strength and endurance in athletes, as well as limitations of studies reviewed and directions for future research. In conclusion, this review highlights the importance of choosing the right and safe nutritional supplements to improve muscle performance in athletes.
... While increased protein intake has been shown to positively impact muscle protein turnover and as a result augment the regeneration of muscle tissue post exercise and promote optimal muscle and strength gains particularly during resistance training (69)(70)(71), it remains unclear as to whether protein supplementation improves the time course of skeletal muscle recovery. A systematic review and meta-analysis showed little effect of protein supplements on recovery from symptoms of EIMD including muscle strength and muscle soreness (72). Another meta-analysis showed that whey protein supplementation had a small to medium temporal ergogenic effect on recovery of muscle function post resistance exercise training, however less than half of the included studies reported a beneficial overall effect (73). ...
IntroductionSports nutrition is a rapidly growing sector with increasing demand for evidence-based nutritional products to support competitive and healthy lifestyles. The product development process for novel foods should rely heavily on end-user engagement to facilitate future success, however there is a dearth of published information available. An understanding of the practices and self-reported nutritional priorities of athletes and active individuals is required for the development of new food products, facilitating evidence-based product formulation.Methods
Participants were at least 18 years of age, actively participating in competitive sport or structured physical activity on at least two occasions per week. Participants were asked to undertake a comprehensive online survey assessing their nutritional practice, perceived nutritional priorities and preferences for product characteristics. Questions were developed on the basis of critical evaluation of the current scientific literature and the hosting of two scoping focus group sessions with prospective end-users.Results405 individuals (29 ± 9 years) completed this questionnaire. 295 participants reported active participation in competitive sport while the remaining 110 participants undertook structured physical activity exclusively. When asked to rank their top three most sought-after product claims in sports nutrition, “enhanced muscular recovery” was the most prioritised receiving 101 first choice preferences (25%) and 295 top 3 preferences. Fifty-eight percent of participants reported taking nutritional supplements. Caffeine containing functional foods (excluding caffeine supplements) were the most commonly used functional food group. A very low incidence of functional food usage was reported otherwise. When asked to rank the importance of various food product attributes, “nutritional profile” was ranked as the most important with rating of 3.37 ± 0.7 out of 4 followed by “taste” and “accessibility”. Whole food nutritional products received the most first preference selections and most top 3 selections when presented with a number of popular performance and recovery products on the market.Conclusions
The transition towards a food first approach in sports nutrition is vital for athletes and active individuals to achieve their goals; with the development of evidence-based functional foods, particularly with a focus on muscle recovery, endurance, and strength enhancement at the forefront for new food product design and innovation.
... training camp compared with the preceding month, which resulted in an increased perceived fatigue, muscle soreness, and a reduced performance in all the study participants. In this effect, protein supplementation might potentially help to accelerate muscle remodeling and recovery during strenuous training [44]. Moreover, the high energy demands of endurance athletes can lead to the oxidation of muscle protein as a fuel (i. ...
Background: The effects of pre-sleep protein supplementation on endurance athletes remain unclear, particularly whether its poten- tial benefits are due to the timing of protein intake or solely to an increased total protein intake. We assessed the effects of pre-sleep protein supplementation in professional cyclists during a training camp accounting for the influence of protein timing.
Methods: Twenty-four professional U23 cyclists (19 ± 1 years, peak oxygen uptake: 79.8 ± 4.9 ml/kg/min) participated in a six-day training camp. Participants were randomized to consume a protein supplement (40 g of casein) before sleep (n = 8) or in the afternoon (n = 8), or an isoenergetic placebo (40 g of carbohy- drates) before sleep (n = 8). Indicators of fatigue/recovery (Hooper index, Recovery–Stress Questionnaire for Athletes, countermove- ment jump), body composition, and performance (1-, 5-, and 20- minute time trials, as well as the estimated critical power) were assessed as study outcomes.
Results: The training camp resulted in a significant (p < 0.001) increase in training loads (e.g. training stress score of 659 ± 122 per week during the preceding month versus 1207 ± 122 during the training camp), which induced an increase in fatigue indicators (e.g. time effect for Hooper index p < 0.001) and a decrease in performance (e.g. time effect for critical power p = 0.002). Protein intake was very high in all the participants (>2.5 g/kg on average), with significantly higher levels found in the two protein supplement groups compared to the placebo group (p < 0.001). No significant between-group differences were found for any of the analyzed outcomes (all p > 0.05). Conclusions: Protein supplementation, whether administered before sleep or earlier in the day, exerts no beneficial effects during a short-term strenuous training period in professional cyclists, who naturally consume a high-protein diet.
... Detailed nutrition recommendations for health and exercise can be found in the ISPAD 2022 Consensus guidelines Chapter 10 for Nutritional Management in Children and Adolescents with Diabetes, along with further advice about nutritional supplements.There is minimal evidence on using protein or other nutritional supplements to support athletic performance in adolescents. Protein supplements in adolescent athletes may not have additional benefits for exercise performance88 although there is some evidence they may reduce post-exercise inflammatory responses88 and have acute benefits on post-exercise muscle anabolism; however, demonstrable muscle damage and recovery changes have not been clearly shown.89 Therefore, protein supplementation should not be routinely recom-mended for youth partaking in regular PA. ...
... Although its functions in intermediate metabolisms have been well documented, mainly regarding muscle fatty acid oxidation and glucose homeostasis [20], there is no scientific evidence to support that carnitine supplementation improves physical performance [17]. On the other hand, amino acids have been largely discussed in the ergogenic scenario [21][22][23][24]. Their role in muscle mass and health-related function is well established [25], although a recent meta-analysis observed minimal effects on the physical performance outcomes of healthy subjects [26]. ...
The main aim of this study was to compare the performance over different distances, the critical velocity (CV), and plasma acylcarnitines/amino acids of male and female adolescent swimmers. Moreover, we applied the complex network approach to identify which molecules are associated with athletes’ performances. On the first day under a controlled environment, blood samples were collected after 12 h of overnight fasting. Performance trials (100, 200, 400, and 800-m) were randomly performed in the subsequent four days in a swimming pool, and CV was determined by linear distance versus time mathematical function. Metabolomic analyses were carried out on a triple quadrupole mass spectrometer performing electrospray ionization in the positive ionization mode. No difference was observed between the performance of male and female swimmers. Except for 200-m distance (p = 0.08), plasma tyrosine was positively and significantly associated with the female times during the trials (100-m, p = 0.04; 400-m, p = 0.04; 800-m, p = 0.02), and inversely associated with the CV (p = 0.02). The complex network approach showed that glycine (0.406), glutamine (0.400), arginine (0.335), free carnitine (0.355), tryptophan (0.289), and histidine (0.271) were the most influential nodes to reach tyrosine. These results revealed a thread that must be explored in further randomized/controlled designs, improving the knowledge surrounding nutrition and the performance of adolescent swimmers.
... In summary, high load intensity of exercise would affect intestinal permeability caused by LPS, which might be related to altering intestinal flora structure in the cecum (Figure 6). Certain dietary supplements might contribute to the prevention of injury induced by exercise (60). Therefore, we found PTE emerging as a promising candidate for a new generation of sports nutrition supplements for athletes. ...
Mounting evidence suggested that high loading intensity of exercise might be detrimental to human health, especially the gastrointestinal tract. Pterostilbene (PTE), derived from grapes and blueberries, might reach a high concentration of intestinal contents. Our study aimed to evaluate PTE’s ability to prevent the loss of intestinal epithelial barrier in high loading intensity of exercise. The exercise model was established by the forced running of mice. An effective HPLC-UV method was developed to quantify PTE concentration in intestinal content. The mRNA changes were detected by quantitative polymerase chain reaction (qPCR). The structure of intestinal flora was analyzed by 16S rRNA sequencing. The PTE (100 mg/kg/d) could significantly attenuate exercise-induced intestinal epithelial barrier loss. Moreover, the HPLC-UV assay showed that the PTE concentration of intestinal content could last 12 h. Furthermore, the exercise increased the abundance of Alistipes, which was related to lipopolysaccharide (LPS) production but could not be reversed by PTE intervention. Besides, cell experiments showed that PTE could promote the expression of intestinal epithelial tight junction (TJ) molecules in vitro. In conclusion, PTE has a significant interest in preventing exercise-induced intestinal damage.
... In spite of the multiple physical stressors involved in sailing, HI doms was preserved during TOR, whereas HI fatigue increased linearly throughout the race and was significantly different from BSL at Post 3 . Nevertheless, it should be noted that sailors were provided protein supplementation onboard and in-between legs to optimize muscular recovery 31 and to avoid muscle atrophy linked to the accumulation of high levels of cortisol during sailing. 9 In fact, sailors had been training regularly 7 months prior to competition, which could have generated morphological adaptations in the muscle fibers necessary to withstand the induced mechanical stress without causing structural alterations. ...
Introduction:
Evidence regarding the impact of offshore sailing on fatigue and readiness variables is conspicuous by its absence. This study investigated the acute effects of an offshore sailing regatta on anthropometry, muscular performance, subjective recovery, and salivary biomarker cortisol.
Methods:
Ten professional offshore sailors from a mixed-sex crew partook in the study (N = 10; mean [SD] age = 32.2 [3.96] y; stature = 179.1 [7.30] cm; body mass = 84.2 [12.1] kg). The race involved 3 offshore legs over a 3-week period. Baseline measures of anthropometry, lower- and upper-body muscular function, perceptions of subjective wellness, and salivary cortisol were assessed 3 hours prior to competition (ie, before the first leg). These measures were repeated within 30 minutes after the cessation of each leg. During each leg, boat movements were recorded via global positioning system units.
Results:
There were significant reductions in lower (effect size [ES] = 0.49) and upper muscular (ES = 0.21) functions, as well as in subjective wellness (ES = 1.65). Salivary cortisol levels increased (ES = 0.84).
Conclusion:
These results demonstrate that, during an intensified period of sailing competition, fatigue will progressively increase. This may impede sailing performance by reducing physical and cognitive efficiency. Furthermore, countermovement jump, handgrip strength, perception of subjective wellness, and cortisol concentration appear to be sensitive measures for monitoring fatigue and readiness in professional sailors.
... Future work should examine the effects of protein sources on muscle damage indices following strenuous exercise. While the present study does not agree with the findings of Brown et al. and Xia et al., as we noted no attenuation in the rise of post-exercise CK concentrations between PRO and PLA groups [27,28], others have reported no benefit of protein supplementation on CK concentrations [29][30][31]. Additionally, in the current study, there appeared to be high variability of CK concentrations between all individuals at each time point, which may have influenced changes over time. ...
Background: To evaluate the effect of pre-sleep protein supplementation after an acute bout of evening resistance training on
next day performance and recovery the following day in physically
active men.
Methods: Eighteen resistance trained men performed a single bout
of resistance exercise then received either a pre-sleep protein (PRO)
supplement containing 40 g of casein protein (PRO; n = 10; mean ±
SD; age = 24 ± 4 yrs; height = 1.81 ± 0.08 m; weight = 84.9 ± 9.5 kg)
or a non-caloric, flavor matched placebo (PLA; n = 8; age = 28 ± 10 yrs;
height = 1.81 ± 0.07 m; weight = 86.7 ± 11.0 kg) 30 min before sleep
(1 h after a standard recovery drink). Blood samples were obtained
pre-exercise and the following morning (+12-h) to measure creatine
kinase and C-reactive protein. Visual analog scales were utilized to
assess perceived pain, hunger, and recovery. One-repetition maximum
(1RM) tests for barbell bench press and squat were performed
pre-exercise and the following morning (+12-h). Statistical
analysis was performed using SPSS (V.23) and p ≤ 0.05 was considered statistically significant.
Results: There were no significant differences between the groups
in next morning performance or muscle damage biomarkers.
However, pre-sleep PRO resulted in a lower perception of hunger
that approached significance the following morning when compared
to PLA (PRO:43.6 ± 31.2, PLA: 69.4 ± 2.22; 95% C.I. = −53.6,
2.0; p = 0.07; d = 0.95).
Conclusions: Following an evening bout of exercise, pre-sleep PRO
did not further improve next morning muscle damage biomarkers
or maximal strength performance in resistance trained men compared
to a non-caloric PLA. However, there may be implications for
lower perceived hunger the next morning with pre-sleep PRO consumption compared to PLA.
... A limitation of this study is that diet was not controlled for the duration of the programme. Both total caloric and macronutrient intake can influence sleep quality (for review see Du et al. 2021), and muscular and joint soreness (for review see Pasiakos et al. 2014). Moreover, hunger and hormonal responses were not recorded throughout the experimental period, while heat is known to alter eating behaviour (Rhoads et al., 2013). ...
Using a parallel randomised control trial to demonstrate the effectiveness of 10 sessions of a Triple Combined Intervention(TCI, far-infrared, negative air ions and light therapy) in reducing stress-related symptoms in workers and detoxify the body.Twenty-one participants were randomly assigned to the experimental group (Gexp, N = 11) or the control group (Gcon, N= 10). The Gexp completed 10 × 20 min sessions using the MLXi3Dome over a 4-week period. Subjective questionnaires were assessed for sleep and psychological disturbances. Trace elements, toxic metals, cortisol, white blood count, muscular and joint soreness level (SL), body weight, resting blood pressure and well-being were also measured. Systolic blood pressure was lower after the 4-week period for Gexp participants only. Sleep improved for Gexp participants and insomnia index decrease significantly. The increase in zinc and copper concentrations were associated with a decrease in the level of lead, mercury and cortisol in the blood following the 10-session programme. An increase in lymphocyte count was reported in the Gexp only. Initial evidence suggests that a triple combined intervention (i.e.MLX i3Dome) reduces excessive stress, improves perceived sleep quality, increases general well-being, enhances body detoxification.
Background: Adequate nutrition is crucial for athletes to enhance performance and recovery. This study investigates the acute effects of omega-3 and whey protein supplementation before and after exercise-induced muscle damage (EIMD) on lower-body strength, explosive power, and delayed-onset muscle soreness (DOMS) in female futsal players. Method: A randomized, cross-over, placebo-controlled, double-blind study involved 15 female futsal players (Age: 22.93 ± 0.54 years; Height: 159.60 ± 1.16 cm; Weight: 56.95 ± 1.79 kg). Participants completed three conditions: pre-EIMD (1000 mg fish oil, 30 g whey protein, 2 h before EIMD), post-EIMD (same supplementation, within 2 h after EIMD), and placebo (PLA, 2 g starch). EIMD involved 200 vertical jumps with 15% body-weighted vests. Metrics including Sargent jump height (VJH), thigh swelling (Sw-T), pressure pain threshold (PPT), V-sit and reach flexibility test (VSFT), range of motion (ROM), relative peak torque (RPT), average power (AP), and maximal voluntary isometric contraction (MVIC) were recorded 48 h post-EIMD. DOMS was assessed via a visual analog scale (VAS) multiple times. A one-week washout period was employed. Results: Pre-EIMD supplementation significantly increased VJH (p = 0.001) compared to PLA and Post-EIMD (p = 0.033). MVIC45° improved significantly in Pre-EIMD vs. PLA (p = 0.001). Improvements were observed in muscle strength metrics, with significant increases in APflx60°/s (pre-EIMD vs. PLA, p = 0.001; pre-EIMD vs. post-EIMD, p = 0.008), APext60°/s (Pre-EIMD vs. PLA, p = 0.030), and APext180°/s (Post-EIMD vs. PLA, p = 0.023). DOMS was lower in both Pre-EIMD and Post-EIMD conditions immediately and at 12 h post-EIMD (p = 0.009; p = 0.030) than PLA. No significant differences were found in Sw-T, PPT, VSFT, ROM, or APflx180°/s. Conclusions: Acute omega-3 and whey protein supplementation, particularly before EIMD, improves strength and power and reduces DOMS in female futsal players. Supplement timing may be critical for optimizing recovery and performance in high-demand sports.
Objectives:
The objective of this study was to examine the difference between the extent of muscle damaging exercise on muscle function variables of vegans and omnivores.
Methods:
Twenty recreationally trained participants completed the study. Participants were assigned to either vegan (n = 10) or omnivore (n = 10) groups. Subjects completed a consent visit followed by 2 visits consisting of running exercise sessions and test familiarization. They returned to the laboratory for visit 4 3-5 days after visit 3 to complete the testing battery. Following the testing, the participants performed a downhill run on the treadmill at -15% grade and approximately 70% of their speed at VO2peak and repeated the testing battery upon completion. Participants were asked to track their food intake. Visits 5, 6, and 7 took place 24, 48, and 72 h following the downhill running protocol, respectively, and consisted of the same testing battery used during visit 4. The detection of differences was performed using two-way (group x time) mixed factorial ANOVA with repeated measures.
Results:
No group x time interactions were noted for running economy or any of the dependent variables. Main effects of time were found for muscle thickness (p<.001) with small effect sizes (d=-0.194 to d=-0.265), pain pressure threshold (p=.002) with medium effect sizes (d=.460 to d=.461), NPRS scale (p<.001) with large effect sizes (d = -0.776 to d=-1.520), and jump height (p<.002) with small to medium effect sizes (d=.304 to d=.438). Nutritional analysis compared the two groups revealed no difference (p>.05) between relative intake of macronutrients and that both exceeded typical recommendations for protein (vegan group - 1.4 g/kg, omnivore group - 1.6 g/kg).
Conclusion:
The lack of differences in recovery between the groups suggests that nutritional adequacy may play a role in recovery. Recovery from downhill running might be influenced by several factors beyond diet, such as exercise protocol intensity, individual fitness levels, and age.
Native plants are adaptable in various environmental conditions in part through the production of unique phytochemicals which may have beneficial effects on human health. Native Australian fruits contain higher phytochemical and antioxidant levels than most Western fruits, suggesting potential for greater health benefits arising from their consumption. These beneficial effects, in turn, may be mediated by the inhibition of inflammatory pathways as well as oxidative stress via the regulation of reactive oxygen (ROS) and/or nitrogen (RNS) species levels. Unaccustomed or strenuous exercise causes muscle damage and soreness, that may be driven by increased ROS and inflammation. There is growing interest in the application of polyphenol-rich food supplementation for the alleviation of exercise-induced oxidative stress, for the reduction of exercise-induced inflammation and improvement of muscle recovery. Therefore, the aim of this review was to provide an overview of the phytochemical and bioactive composition of some Australian native plant foods and their potential use for functional food development in the management of muscle recovery and inflammation. Native plant foods and food products could be beneficial for reducing inflammation, though it is important to note that most of the research in this field has been conducted in animal models or in vitro, in addition to there being little data on skeletal muscle inflammation. Further studies, particularly in humans, would be needed to confirm these effects and to determine the appropriate dosages and forms of native foods and food products for consumption to reduce inflammation and enhance muscle recovery.
Eccentric muscle contractions can cause structural damage to muscle cells resulting in temporarily decreased muscle force production and soreness. Prior work indicates pasture-raised dairy products from grass-fed cows have greater anti-inflammatory and antioxidant properties compared to grain-fed counterparts. However, limited research has evaluated the utility of whey protein from pasture-raised, grass-fed cows to enhance recovery compared to whey protein from non-grass-fed cows. Therefore, using a randomized, placebo-controlled design, we compared the effect of whey protein from pasture-raised, grass-fed cows (PRWP) to conventional whey protein (CWP) supplementation on indirect markers of muscle damage in response to eccentric exercise-induced muscle damage (EIMD) in resistance-trained individuals. Thirty-nine subjects (PRWP, n = 14; CWP, n = 12) completed an eccentric squat protocol to induce EIMD with measurements performed at 24, 48, and 72 h of recovery. Dependent variables included: delayed onset muscle soreness (DOMS), urinary titin, maximal isometric voluntary contraction (MIVC), potentiated quadriceps twitch force, countermovement jump (CMJ), and barbell back squat velocity (BBSV). Between-condition comparisons did not reveal any significant differences (p ≤ 0.05) in markers of EIMD via DOMS, urinary titin, MIVC, potentiated quadriceps twitch force, CMJ, or BBSV. In conclusion, neither PRWP nor CWP attenuate indirect markers of muscle damage and soreness following eccentric exercise in resistance-trained individuals.
Recreational runners are prone to injury, leading to decreased levels of physical activity and well-being. Fortunately, injury prevention methods reduce risk and can benefit athletic performance. By synthesizing current literature, this paper details how nutrition, sleep, stretching, and thermotherapy can improve muscular recovery to avoid injury. Fat, protein, carbohydrate, caffeine, water, and electrolyte consumption should be moderated by general guidelines and personalized based on energy expenditure. While disturbed sleep patterns have minimized effects on running performance, runners should avoid sleep deprivation due to its detrimental impact on muscular recovery and mental health. Consistent and well-validated recovery techniques should be used, such as applying cold therapies immediately post-exercise and heat therapies later in the recovery process. For warmups, prioritizing dynamic stretching over static, ballistic, or PNF stretching is also recommended to protect the runner from muscular strain by maintaining a healthy range of motion across joints. By incorporating strategies from each category into a comprehensive recovery routine, intermediate and novice runners can protect and prolong their ability to be physically fit.
Background and Objectives Supplementation with amino acids for muscle recovery can be effective on oxidative stress and muscle damage. This study aims to compare the effects of pea protein and whey protein supplements on muscle damage, delayed onset muscle soreness (DOMS), and functional performance after high-intensity functional training (HIFT) bout in untrained overweight young men. Subjects and Methods In this randomized, double-blind, placebo-controlled clinical trial, 30 untrained overweight young men were selected by a purposive sampling method and divided randomly into three different groups of pea protein (n=10), Whey Protein (n=10), and placebo (n=10). Variables related to muscle damage and DOMS were measured 24 hours after HIFT. Repeated measures ANOVA and Bonferroni post hoc test were used to compare the differences between groups. Results There was a significant difference between the two evaluation stages. There was a significant difference between the Whey protein and pea protein groups compared to the placebo group (P<0.05), but no significant difference was found between the Whey protein and pea protein groups (P<0.05). Conclusion The use of Whey protein, compared to pea protein, can reduce muscle damage and DOMS following HIFT
Nutrition is increasingly recognized as a key component of optimal sporting performance, with both the science and practice of sports nutrition developing rapidly. The sports nutrition market has witnessed robust growth in the past few years; it is gaining pace due to the increase in health awareness among the population, new product development, the rapid increase in urbanization, and growth in a number of sales outlets, health clubs, fitness centers and gyms. Athletes use a range of nutritional and diet strategies to improve sports performance. Nutrition plans need to be personalized to the individual athlete to take into account the specificity and uniqueness of the event, performance goals, practical challenges, food preferences, and responses to various strategies. A key factor is the related marketing used to reach the core aim of the athletes for specific sports nutrition so they can meet their energy and nutrient requirements, whether that is speed, endurance, recovery, or strength. The marketing strategies in the sports nutrition industry are wide. Companies understand the power of sports endorsement, the trending on social media, and after all the factors of advertisement, through the different marketing communication channels impacting the athletes’ behavior for the final decision-making process of purchasing the product. In this paper the purpose is to investigate the effect of sport-related nutritional marketing as a communication strategy reaching athletes, and, its second relationship, the effect of the marketed sport-related nutritional products impact on athlete’s performance, from the athlete’s aspect. The importance of this paper is to examine a new topic of a connection between sports nutritional marketing and the eventual performance effect on a particular sub-category of athletes because very little research is being conducted on this topic of interest. The research framework used in this paper will help to guide future research and improve marketing communication strategies with great insight on what are the key methods to reach out to short and distance athletes from a marketing point of view, as well as the key factors that make marketed sport nutritional products impact on athlete’s performance.
The research is a field study on the effect of taking protein supplements on a group of players of different ages and comparing them with their counterparts who did not take protein supplements while following a balanced diet and exercise program only. The study included 48 players and volunteers who were divided into three groups according to the age groups A (20-29 years), B (30-39 years) and C (40-50 years), and each group was divided into two parts, the first used protein supplements of 25 grams per day and the second Supplements were not used, and a survey questionnaire was conducted on the foods the players eat as a protein food source. Coach Hussein Anisafi contributed to the selection of the players and gave from his experience, which enriched the study. The study found that the highest frequency of food eaten by the athlete as a protein food source is eggs, followed by chicken breast, and that their trainer is the source of their confidence and guidance towards taking protein supplements and adopting a balanced diet. Protein content on the biceps muscle of players with the age groups of the players, it was found that the players in the young age group A had an increase in muscle amplification higher than other age groups and tended more to take supplements in order to obtain the desired muscle size and shape, while the second age group B They did not get the desired result, but they depended more on the training program and diet more, and this may be due to their long experience in the field of training and the quality of eating. With regard to age group C, the change was slight, as taking protein supplements was not accompanied by a clear change in muscle amplification. Additional types of supplements had to be used other than the supplements used in the study.
Athletes are bombarded with nutritional/dietary supplements (NSs/DSs) that promise to improve health, function, and performance. Many of these claims, however, are based on little evidence, and the efficacy and safety of many products are debatable. A review of doping, risk factors, protective factors, performance enhancement, sports performance, dietary supplements, nutritional supplements (NSs), and health consequences was completed using PubMed, Google Scholar, Web of Science, and Science Direct. The inclusion criteria were studies published up until June 2021, which analyzed the content of nutritional/dietary substances and their influence on sports performance. Seventy-three review articles were included in this review. In summary, supplementation will always be a part of athletes’ careers due to its perception of ergogenic capabilities, and there is evidence of some dietary nutritional supplements DSs/NSs substances supporting performance enhancement and recovery. However, there is data that due to real harm and unethical manufacturing and marketing practices, some products may contain unwanted/illegal substances. Athletes should be aware of the risk of being tested positive due to contamination of NSs/DSs with a World Anti-Doping Agency (WADA)-banned substance. Athletes and coaches should stick only to supplements that show strong research evidence supporting sports performance and safety use.
Athletes are bombarded with nutritional/dietary supplements (NSs/DSs) that promise to improve health, function, and performance. Many of these claims, however, are based on little evidence, and the efficacy and safety of many products are debatable. A review of doping, risk factors, protective factors, performance enhancement, sports performance, dietary supplements, nutritional supplements (NSs), and health consequences was completed using PubMed, Google Scholar, Web of Science, and Science Direct. The inclusion criteria were studies published up until June 2021, which analyzed the content of nutritional/dietary substances and their influence on sports performance. Seventy-three review articles were included in this review. In summary, supplementation will always be a part of athletes' careers due to its perception of ergogenic capabilities, and there is evidence of some dietary nutritional supplements DSs/NSs substances supporting performance enhancement and recovery. However, there is data that due to real harm and unethical manufacturing and marketing practices, some products may contain unwanted/illegal substances. Athletes should be aware of the risk of being tested positive due to contamination of NSs/DSs with a World Anti-Doping Agency (WADA)-banned substance. Athletes and coaches should stick only to supplements that show strong research evidence supporting sports performance and safety use. | KEYWORDS Performance enhancement; dietary supplements; nutritional supplement; doping; health; risk factors.
Protein supplements (PSs) are, after multivitamins, the most frequently consumed dietary supplement by U.S. military personnel. Warfighters believe that PSs will improve health, promote muscle strength, and enhance physical performance. The estimated prevalence of regular PS use by military personnel is nearly 20% or more in active-duty personnel, which is comparable to collegiate athletes and recreationally active adults, but higher than that for average U.S. civilians. Although the acute metabolic effects of PS ingestion are well described, little is known regarding the benefits of PS use by warfighters in response to the metabolic demands of military operations. When dietary protein intake approaches 1.5 g ⋅ kg(-1) ⋅ d(-1), and energy intake matches energy expenditure, the use of PSs by most physically active military personnel may not be necessary. However, dismounted infantry often perform operations consisting of long periods of strenuous physical activity coupled with inadequate dietary energy and protein intake. In these situations, the use of PSs may have efficacy for preserving fat-free mass. This article reviews the available literature regarding the prevalence of PS use among military personnel. Furthermore, it highlights the unique metabolic stressors affecting U.S. military personnel and discusses potential conditions during which protein supplementation might be beneficial.
Background
Owing to the mechanics of anti-doping regulation via the World Anti-Doping Agency's Prohibited List, nutritional supplement use received little attention in comparison to the prevalence of doping. The aims of this study were to investigate supplement use, identify groups of athletes with high levels of supplement use and the prevalence of concomitant use of supplements.
Methods
Survey data from 847 high-performing athletes in the UK were analysed using descriptive statistics. The survey, conducted by UK Sport, consisted of questions regarding knowledge of the prohibited substances, testing procedure, nutritional supplement use and perceptions of the doping problem. The proportion of supplement users and the relative use of each supplement were compared by age, gender and professional status.
Results
Among 874 high-performing athletes in the UK sample, 58.8% of them reported the use of at least one nutritional supplement. Among supplement users, 82.6% used more than one and 11.5% reported use of more than five nutritional supplements. Of the 9 supplements listed, multivitamins (72.6%) and vitamin C (70.7%) were used most, followed by creatine (36.1%), whey protein (31.7%), echinacea (30.9%), iron (29.9%) and caffeine (23.7%). Less than 11% reported the use of magnesium or ginseng. Creatine use was typically associated with males regardless of status and across all ages, whereas iron was characteristically used by females. A 'typical' supplement user is male, between 24 and 29 years of age, involved in professional sport and using a combination of supplements. Male professional players between age 30 and 34 years, and female non-professional athletes between 24 and 29 years of age also represented a considerable proportion of supplement users. Athletes older than 40 years of age were practically non-users. Concomitant use of supplements is characteristic of male users more than females.
Conclusion
As supplement use has been previously shown to increase the probability of prohibited substance use, groups exhibiting high use of nutritional supplements should be monitored. Future research should incorporate a wide range of supplements and enquire about the daily amount ingested. In addition to tutoring, preventive measures should incorporate offering acceptable and healthy alternatives for assisted performance enhancement.
Exercise-induced muscle damage (EIMD) leads to the degradation of protein structures within the muscle. This may subsequently lead to decrements in muscle performance and increases in intramuscular enzymes and delayed-onset muscle soreness (DOMS). Milk, which provides protein and carbohydrate (CHO), may lead to the attenuation of protein degradation and (or) an increase in protein synthesis that would limit the consequential effects of EIMD. This study examined the effects of acute milk and milk-based proteinCHO (CHO-P) supplementation on attenuating EIMD. Four independent groups of 6 healthy males consumed water (CON), CHO sports drink, milk-based CHO-P or milk (M), post EIMD. DOMS, isokinetic muscle performance, creatine kinase (CK), and myoglobin (Mb) were assessed immediately before and 24and 48h after EIMD. DOMS was not significantly different (p> 0.05) between groups at any time point. Peak torque (dominant) was significantly higher (p< 0.05) 48h after CHO-P compared with CHO and CON, and M compared with CHO. Total work of the set (dominant) was significantly higher (p< 0.05) 48h after CHO-P and M compared with CHO and CON. CK was significantly lower (p< 0.05) 48 h after CHO-P and M compared with CHO. Mb was significantly lower (p< 0.05) 48 h after CHO-P compared with CHO. At 48h post-EIMD, milk and milk-based proteinCHO supplementation resulted in the attenuation of decreases in isokinetic muscle performance and increases in CK and Mb.
The purpose of this study was to determine whether a practical leucine-protein, high-carbohydrate postexercise feeding regimen could improve recovery, as measured by subsequent cycling performance and mechanistic markers, relative to control feeding. In a crossover, 10 male cyclists performed 2- to 2.5-h interval training bouts on 3 consecutive evenings, ingesting either leucine-protein, high-carbohydrate nutrition (0.1/0.4/1.2/0.2 g·kg–1·h–1; leucine, protein, carbohydrate, fat, respectively) or isocaloric control (0.06/1.6/0.2 g·kg–1·h–1; protein, carbohydrate, fat, respectively) nutrition for 1.5 h postexercise. Throughout the experimental period diet was controlled, energy and macronutrient intake balanced, and protein intake clamped at 1.6 g·kg–1·day–1. The alternate supplement was provided the next morning, thereby isolating the postexercise nutrition effect. Following 39 h of recovery, cyclists performed a repeat-sprint performance test. Postexercise leucine-protein ingestion improved mean sprint power by 2.5% (99% confidence limit, ±2.6%; p = 0.013) and reduced perceived overall tiredness during the sprints by 13% (90% confidence limit, ±9.2%), but perceptions of leg tiredness and soreness were unaffected. Before exercise, creatine-kinase concentration was lowered by 19% (90% confidence limits, ±18%), but lactate dehydrogenase and pressure-pain threshold were unaltered. There was a small reduction in anger (25% ± 18%), but other moods were unchanged. Plasma leucine (3-fold) and essential amino acid (47%) concentrations were elevated postexercise. Net nitrogen balance trended mildly negative in both conditions (mean ± SD: leucine-protein, –20 ± 46 mg·kg–1 per 24 h; control, –25 ± 36 mg·kg–1 per 24 h). The ingestion of a leucine-protein supplement along with other high-carbohydrate food following intense training on consecutive days enhances subsequent high-intensity endurance performance and may attenuate muscle membrane disruption in well-trained male cyclists.
Laboratory-based studies have demonstrated that adding protein (PRO) to a carbohydrate (CHO) supplement can improve thermoregulatory capacity, exercise performance and recovery. However, no study has investigated these effects in a competitive sporting context. This study assessed the effects of combined CHO-PRO supplementation on physiological responses and exercise performance during 8 days of strenuous competition in a hot environment. Twenty-eight cyclists participating in the TransAlp mountain bike race were randomly assigned to fitness-matched placebo (PLA 76 g L(-1) CHO) or CHO-PRO (18 g L(-1) PRO, 72 g L(-1) CHO) groups. Participants were given enough supplements to allow ad libitum consumption. Physiological and anthropometric variables were recorded pre- and post-exercise. Body mass decreased significantly from race stage 1 to 8 in the PLA group (-0.75 ± 0.22 kg, P = 0.01) but did not change in the CHO-PRO group (0.42 ± 0.42 kg, P = 0.35). Creatine kinase concentration and muscle soreness were substantially elevated during the race, but were not different between groups (P = 0.82, P = 0.44, respectively). Urine osmolality was significantly higher in the CHO-PRO versus the PLA group (P = 0.04) and the rise in tympanic temperature from pre- to post-exercise was significantly less in CHO-PRO versus PLA (P = 0.01). The CHO-PRO group also completed the 8 stages significantly quicker than the PLA group (2,277 ± 127 vs. 2,592 ± 68 min, respectively, P = 0.02). CHO-PRO supplementation therefore appears to prevent body mass loss, enhance thermoregulatory capacity and improve competitive exercise performance despite no effect on muscle damage.
US Army soldiers engage in strenuous activities and must maintain fitness and body weight to retain their jobs. Anecdotal reports suggest that the use of dietary supplements (DSs) by soldiers may reflect their unique occupational requirements and the complexity of their job and family responsibilities.
We assessed the use of DSs by soldiers.
We conducted a survey of 990 randomly selected soldiers at 11 army bases globally. Data were weighted by age, sex, rank, and Special Forces status to represent the active-duty army.
Overall, 53% of soldiers reported the use of DSs ≥1 time/wk; 23% of soldiers used sports beverages, 6% of soldiers used sports bars or gels, and 3% of soldiers reported the use of meal-replacement beverages. Most commonly used DSs were multivitamins or multiminerals (37.5%), protein and amino acids (18.7%), individual vitamins and minerals (17.9%), combination products (9.1%), and herbal supplements (8.3%). Many soldiers reported the use of performance-enhancement and weight-reduction products, and 22% of soldiers consumed ≥3 different DSs/wk. Logistic regression modeling indicated that older age, educational attainment, higher body mass index, and strength training were associated with DS use (P < 0.05). Reported reasons for DS use were to improve health (64%), provide more energy (31%), increase muscle strength (25%), and enhance performance (17%). Among DS users, mean monthly expenditures on DSs were 50/mo.
Soldiers, like civilians, use large amounts of DSs, often in combination. Soldiers use more DSs purported to enhance performance than civilians use when matched for key demographic factors. These differences may reflect the unique occupational demands and stressors of military service.
The purpose of this study was to investigate whether short-term amino acid supplementation could maintain a short-term net anabolic hormonal profile and decrease muscle cell damage during a period of high-intensity resistance training (overreaching), thereby enhancing recovery and decreasing the risk of injury and illness. Eight previously resistance trained males were randomly assigned to either a high branched chain amino acids (BCAA) or placebo group. Subjects consumed the supplement for 3 weeks before commencing a fourth week of supplementation with concomitant high-intensity total-body resistance training (overreaching) (3 x 6-8 repetitions maximum, 8 exercises). Blood was drawn prior to and after supplementation, then again after 2 and 4 days of training. Serum was analyzed for testosterone, cortisol, and creatine kinase. Serum testosterone levels were significantly higher (p < 0.001), and cortisol and creatine kinase levels were significantly lower (p < 0.001, and p = 0.004, respectively) in the BCAA group during and following resistance training. These findings suggest that short-term amino acid supplementation, which is high in BCAA, may produce a net anabolic hormonal profile while attenuating training-induced increases in muscle tissue damage. Athletes' nutrient intake, which periodically increases amino acid intake to reflect the increased need for recovery during periods of overreaching, may increase subsequent competitive performance while decreasing the risk of injury or illness.
This study examined the effect of carbohydrate and whey protein supplements on recovery of neuromuscular function after prolonged load carriage.
TEN MALE PARTICIPANTS (BODY MASS: 81.5 +/- 10.5 kg, age: 28 +/- 9 years, O(2)max: 55.0 +/- 5.5 ml.kg(-1).min(-1)) completed three treadmill walking tests (2 hr, 6.5 km.h(-1)), carrying a 25 kg backpack consuming 500 ml of either: (1) Placebo (flavoured water) [PLA], (2) 6.4% Carbohydrate Solution [CHO] or (3) 7.0% Whey Protein Solution [PRO]. For three days after load carriage, participants consumed two 500 ml supplement boluses. Muscle performance was measured before and at 0, 24, 48 and 72 h after load carriage, during voluntary and electrically stimulated contractions.
Isometric knee extension force decreased immediately after load carriage with no difference between conditions. During recovery, isometric force returned to pre-exercise values at 48 h for CHO and PRO but at 72 h for PLA. Voluntary activation decreased immediately after load carriage and returned to pre-exercise values at 24 h in all conditions (P = 0.086). During recovery, there were no differences between conditions for the change in isokinetic peak torque. Following reductions immediately after load carriage, knee extensor and flexor peak torque (60 degrees .s(-1)) recovered to pre-exercise values at 72 h. Trunk extensor and flexor peak torque (15 degrees .s(-1)) recovered to pre-exercise values at 24 h (P = 0.091) and 48 h (P = 0.177), respectively.
Recovery of neuromuscular function after prolonged load carriage is improved with either carbohydrate or whey protein supplementation for isometric contractions but not for isokinetic contractions.
The aim of this paper was to assess the effects of branched-chain amino acid (BCAA) supplementation on muscle soreness, muscle damage and inflammation during an intensive training program.
Twelve long-distance runners (20 + or - 1 year-old) participated in a double-blinded crossover designed study conducted during two intensive training periods (three-day). The subjects were provided either a drink containing BCAA (0.8% BCAA in a 3.5% carbohydrate solution; 2,500 mL/day) or an isocaloric placebo drink during each training period. All subjects completed the same training program (total running distance: males: 86 km, females: 64 km), and ate the same meals during the training period. Whole body muscle soreness and fatigue sensation were measured in the morning before and during the training period by Visual Analogue Scale method. Plasma creatine kinase (CK), lactate dehydrogenase (LDH), and granulocyte elastase (GEL) levels were measured as indicators of muscle damage and inflammation before and after the training period.
Muscle soreness and fatigue sensation during the training period in the BCAA trial were lower than those in the placebo trial (-32% and -24%, respectively; P<0.05). The plasma CK, LDH, and GEL levels after the training program in the BCAA trial were lower than those in the placebo trial (-21%, -6%, and -15%, respectively; P<0.05).
These results demonstrate that BCAA supplementation during an intensive training program effectively reduces the muscle soreness and fatigue sensation, and that the perceived changes could be attributed to the attenuation of muscle damage and inflammation.
To maximize training quality, athletes have sought nutritional supplements that optimize recovery. This study compared chocolate milk (CHOC) with a carbohydrate replacement beverage (CRB) as a recovery aid after intense exercise, regarding performance and muscle damage markers in trained cyclists. Ten regional-level cyclists and triathletes (maximal oxygen uptake 55.2 7.2mLkg¹min¹) completed a high-intensity intermittent exercise protocol, then 1518h later performed a performance trial at 85% of maximal oxygen uptake to exhaustion. Participants consumed 1.0 g carbohydratekg¹h¹ of a randomly assigned isocaloric beverage (CHOC or CRB) after the first high-intensity intermittent exercise session. The same protocol was repeated 1 week later with the other beverage. A 1-way repeated measures analysis of variance revealed no significant difference (p = 0.91) between trials for time to exhaustion at 85% of maximal oxygen uptake (CHOC 13 10.2min, CRB 13.5 8.9min). The change in creatine kinase (CK) was significantly (p< 0.05) greater in the CRB trial than in the CHOC trial (increase CHOC 27.9 134.8 UL¹, CRB 211.9 192.5 UL¹), with differences not significant for CK levels before the second exercise session (CHOC 394.8 166.1 UL¹, CRB 489.1 264.4UL¹) between the 2 trials. These findings indicate no difference between CHOC and this commercial beverage as potential recovery aids for cyclists between intense workouts.
Essential amino acids (EAA) stimulate muscle protein synthesis in humans. However, little is known about whether microRNAs (miRNA) and genes associated with muscle growth are expressed differently following EAA ingestion. Our purpose in this experiment was to determine whether miRNA and growth-related mRNA expressed in skeletal muscle are up- or downregulated in humans following the ingestion of EAA. We hypothesized that EAA would alter miRNA expression in skeletal muscle as well as select growth-related genes. Muscle biopsies were obtained from the vastus lateralis of 7 young adult participants (3 male, 4 female) before and 3 h after ingesting 10 g of EAA. Muscle samples were analyzed for muscle miRNA (miR-499, -208b, -23a, -1, -133a, and -206) and muscle-growth related genes [MyoD1, myogenin, myostatin, myocyte enhancer factor C (MEF2C), follistatin-like-1 (FSTL1), histone deacytylase 4, and serum response factor mRNA] before and after EAA ingestion using real-time PCR. Following EAA ingestion, miR-499, -208b, -23a, -1, and pri-miR-206 expression increased (P < 0.05). The muscle-growth genes MyoD1 and FSTL1 mRNA expression increased (P < 0.05), and myostatin and MEF2C mRNA were downregulated following EAA ingestion (P < 0.05). We conclude that miRNA and growth-related genes expressed in skeletal muscle are rapidly altered within hours following EAA ingestion. Further work is needed to determine whether these miRNA are post-transcriptional regulators of growth-related genes following an anabolic stimulus.
Previous studies indicate that exercise-induced muscle damage may be attenuated when protein is included in a carbohydrate recovery supplement. This study was designed to examine systemic indices of muscle damage, inflammation, and recovery of muscle function, following strenuous exercise, with ingestion of either carbohydrate alone or a carbohydrateprotein mixture. Seventeen highly trained volunteers participated in 2 trials in a randomized order, separated by approximately 9weeks. Each trial involved 90min of intermittent shuttle-running, either with ingestion of a 9% sucrose solution during and for 4h after (1.2gkg¹ body massh¹) or with the same solution plus 3% whey protein isolate (0.4gkg¹ body massh¹). Blood was sampled throughout and 24h after each trial to determinate the systemic indices of muscle damage and inflammation. An isokinetic dynamometer was used to establish reliable baseline measurements of peak isometric torque for knee and hip flexors and extensors, which were then followed-up at 4-, 24-, 48-, and 168-h postexercise. The exercise protocol resulted in significantly elevated variables indicative of muscle damage and inflammation, while peak isometric torque was immediately reduced by 10%20% relative to baseline, across all muscle groups tested. However, none of these responses varied in magnitude or time-course between the treatments, or between participants first and second trials. The addition of whey protein isolate to a dietary carbohydrate supplement ingested during and for 4h following strenuous exercise did not attenuate systemic indices of muscle damage or inflammation, nor did it restore muscle function more rapidly than when the carbohydrate fraction was ingested alone.
The effect of 42 g of protein ingested pre- and post-exercise on recovery from an acute resistance exercise session was examined in 15 male strength/power athletes who were randomly divided into a supplement (SUP) or placebo (PL) group. Subjects reported to the Human Performance Laboratory (HPL) on four separate occasions (T1-T4). Maximal strength [one repetition-maximum (1-RM)] testing was performed during T1. During T2 subjects performed four sets of ten repetitions at 80% of their 1-RM in the squat, dead lift and barbell lunge exercises with 90 s of rest between each set. Blood draws occurred at baseline (BL), immediate and 15 min post-exercise to determine testosterone, cortisol and creatine kinase (CK) concentrations. Subjects reported back to the HPL 24 (T3) and 48 h (T4) post-exercise for a BL blood draw and to perform four sets of ten repetitions with 80% of 1-RM for the squat exercise only. No differences in the number of repetitions performed in the squat exercise were seen between the groups at T2. Relative to T2, PL performed significantly (P < 0.05) fewer repetitions than SUP at T3 and T4 (-9.5 +/- 5.5 repetitions vs. -3.3 +/- 3.6 during T3, respectively, and -10.5 +/- 8.2 repetitions vs. -2.3 +/- 2.9 repetitions during T4, respectively). No differences in hormonal measures were seen between the groups. CK concentrations were significantly (P < 0.05) elevated at T3 for both groups, but continued to elevate (P < 0.05) at T4 for PL only. No significant group differences were noted for CK at any time point. Results indicate that a proprietary protein SUP consumed before and after a resistance training session significantly contributes to improvements in exercise recovery 24 and 48 h post-exercise.
A study of a sample provides only an estimate of the true (population) value of an outcome statistic. A report of the study therefore usually includes an inference about the true value. Traditionally, a researcher makes an inference by declaring the value of the statistic statistically significant or nonsignificant on the basis of a P value derived from a null-hypothesis test. This approach is confusing and can be misleading, depending on the magnitude of the statistic, error of measurement, and sample size. The authors use a more intuitive and practical approach based directly on uncertainty in the true value of the statistic. First they express the uncertainty as confidence limits, which define the likely range of the true value. They then deal with the real-world relevance of this uncertainty by taking into account values of the statistic that are substantial in some positive and negative sense, such as beneficial or harmful. If the likely range overlaps substantially positive and negative values, they infer that the outcome is unclear; otherwise, they infer that the true value has the magnitude of the observed value: substantially positive, trivial, or substantially negative. They refine this crude inference by stating qualitatively the likelihood that the true value will have the observed magnitude (eg, very likely beneficial). Quantitative or qualitative probabilities that the true value has the other 2 magnitudes or more finely graded magnitudes (such as trivial, small, moderate, and large) can also be estimated to guide a decision about the utility of the outcome.
Sarcopenia, skeletal muscle loss during aging, is associated with increased falls, fractures, morbidity, and loss of independence. MicroRNAs (miRNAs) are novel posttranscriptional regulators. The role of miRNAs in cell size regulation after an anabolic stimulus in human skeletal muscle is unknown. We hypothesized that aging would be associated with a differential expression of skeletal muscle primary miRNA (pri-miRNA) and mature miRNA (miR). To test this hypothesis, we used real-time PCR and immunoblotting before and after an anabolic stimulus (resistance exercise + ingestion of a 20-g leucine-enriched essential amino acid solution) to measure the expression of muscle-specific miRNAs (miR-1, miR-133a, and miR-206), upstream regulators (MyoD and myogenin), and downstream targets [insulin-like growth factor-I, histone deacetylase-4, myocyte enhancing factor-2, and Ras homolog enriched in brain (Rheb)] in skeletal muscle of young and older men. Muscle biopsies were obtained at baseline and 3 and 6 h after exercise. At baseline, we found pri-miRNA-1-1, -1-2, -133a-1, and -133a-2 expression elevated in older compared with young men (P < 0.05). Pri-miRNA-1-2, -133a-1, and -133a-2 were reduced at 6 h after exercise only in the young men compared with baseline, whereas pri-miRNA-206 was elevated at different postexercise time points in older and young men (P < 0.05). Compared with baseline, miR-1 was reduced only in the young men, whereas Rheb protein was increased in both age groups after the anabolic stimulus (P < 0.05). We conclude that skeletal muscle primary and mature miRNA expression in young men is readily altered by an anabolic stimulus of resistance exercise + essential amino acid ingestion. However, aging is associated with higher basal skeletal muscle primary miRNA expression and a dysregulated miRNA response after the anabolic stimulus.
Pain, stiffness, and indicators of muscle damage occur at different times after eccentric muscle action. After a single bout of maximal resisted lengthening of the elbow flexors, elbow position, pain perception, and indicators of cellular damage were measured. Immediately postexercise, a significant decrease in resting muscle length was observed that continued to 48 h. At this time, an increase in perceived muscle soreness was noted (P less than 0.05), and a biopsy of the biceps brachii revealed mast cell degranulation, separations of the extracellular matrix from myofibers, and increased plasma constituents in the extracellular space. It is proposed that myofiber disruption allows intracellular proteins to escape and extracellular proteins and ions to enter, causing swelling, whereas the disrupted extracellular matrix initiates the inflammatory response, which includes the release of mast cell granules seen at 48 h postexercise. Thus the delayed sensation of pain (soreness) after repeated eccentric muscle actions probably results from inflammation in response to extracellular matrix disruption.
Five women and three men (aged 24-43 yr) performed maximal eccentric contractions of the elbow flexors (for 20 min) on three occasions, spaced 2 wk apart. Muscle pain, strength and contractile properties, and plasma creatine kinase (CK) were studied before and after each exercise bout. Muscle tenderness was greatest after the first bout and thereafter progressively decreased. Very high plasma CK levels (1,500-11,000 IU/l) occurred after the first bout, but the second and third bouts did not significantly affect the plasma CK. After each bout the strength was reduced by approximately 50% and after 2 wk had only recovered to 80% of preexercise values. Each exercise bout produced a marked shift of the force-frequency curve to the right which took approximately 2 wk to recover. The recovery rate of both strength and force-frequency characteristics was faster after the second and third bouts. Since the adaptation occurred after the performance of maximal contractions it cannot have been a result of changes in motor unit recruitment. The observed training effect of repeated exercise was not a consequence of the muscle becoming either stronger or more resistant to fatigue.
Muscle ultrastructure and contractile properties were examined before and after a single bout of resistance exercise (8 sets of 8 repetitions at 80% of 1 repetition maximum). Eight untrained males performed the concentric (Con) phase of arm-curl exercise with one arm and the eccentric (Ecc) phase with the other arm. Needle biopsies were obtained from biceps brachii before exercise (Base), immediately postexercise from each arm (post-Con and post-Ecc), and 48 h postexercise from each arm (48 h-Con and 48 h-Ecc). Electron microscopy was used to quantify the presence of disrupted fibers in each sample. Analysis of variance revealed a greater (P < or = 0.05) proportion of disrupted fibers in post-Con, post-Ecc, 48 h-Con, and 48 h-Ecc samples compared with Base. Significantly more fibers were disrupted in post-Ecc (82%) and 48 h-Ecc (80%) samples compared with post-Con (33%) and 48 h-Con (37%), respectively. Voluntary and evoked strength measurements recovered to Base values within 24 h in the Con arm but remained depressed (P < or = 0.05) for 72-96 h in the Ecc arm. These data indicate that both the raising and lowering phases of weightlifting produced myofibrillar disruption, with the greatest disruption occurring during the lowering phase.
The authors investigated the effects of postexercise carbohydrate-protein- anti-oxidant (CHO+P+A) ingestion on plasma creatine kinase (CK), muscle soreness, and subsequent cross-country race performance. Twenty-three runners consumed 10 mL/kg body weight of CHO or CHO+P+A beverage immediately after each training session for 6 d before a cross-country race. After a 21-d washout period, subjects repeated the protocol with the alternate beverage. Postintervention CK (223.21 ± 160.71 U/L; 307.3 ± 312.9 U/L) and soreness (medians = 1.0, 2.0) were significantly lower after CHO+P+A intervention than after CHO, despite no differences in baseline measures. There were no overall differences in running performance after CHO and CHO+P+A interventions. There were, however, significant correlations between treatment differences and running mileage, with higher mileage runners having trends toward improved attenuations in CK and race performance after CHO+P+A intervention than lower mileage runners. We conclude that muscle damage incurred during training was attenuated with postexercise CHO+P+A ingestion, which could lead to performance improvements in high-mileage runners.
Endurance athletes commonly consume carbohydrate-electrolyte sports beverages during prolonged events. The benefits of this strategy are numerous--sports-beverage consumption during exercise can delay dehydration, maintain blood glucose levels, and potentially attenuate muscle glycogen depletion and central fatigue. Thus, it is generally agreed that carbohydrate-electrolyte beverages can improve endurance performance. A controversy has recently emerged regarding the potential role of protein in sports beverages. At least 3 recent studies have reported that carbohydrate-protein ingestion improves endurance performance to a greater extent than carbohydrate alone. In addition, carbohydrate-protein ingestion has been associated with reductions in markers of muscle damage and improved postexercise recovery.Although many of these muscle damage and recovery studies examined postexercise nutritional intake, recent evidence suggests that these benefits may be elicited with carbohydrate-protein consumption during exercise. These findings are intriguing and suggest that the importance of protein for endurance athletes has been underappreciated. However, 2 studies recently reported no differences in endurance performance between carbohydrate and carbohydrate-protein beverages. The varied outcomes may have been influenced by a number of methodological differences, including the amounts and types of carbohydrate or protein in the beverages, the exercise protocols, and the relative statistical power of the studies. In addition, although there are plausible mechanisms that could explain the ergogenic effects of carbohydrate-protein beverages, they remain relatively untested. This review examines the existing research regarding the efficacy of carbohydrate-protein consumption during endurance exercise. Limitations of the existing research are addressed, as well as potential areas for future study.
Ferguson-Stegall, L, McCleave, EL, Ding, Z, Doerner III, PG, Wang, B, Liao, Y-H, Kammer, L, Liu, Y, Hwang, J, Dessard, BM, and Ivy, JL. Postexercise carbohydrate-protein supplementation improves subsequent exercise performance and intracellular signaling for protein synthesis. J Strength Cond Res 25(5): 1210-1224, 2011-Postexercise carbohydrate-protein (CHO + PRO) supplementation has been proposed to improve recovery and subsequent endurance performance compared to CHO supplementation. This study compared the effects of a CHO + PRO supplement in the form of chocolate milk (CM), isocaloric CHO, and placebo (PLA) on recovery and subsequent exercise performance. Ten cyclists performed 3 trials, cycling 1.5 hours at 70% V̇o2max plus 10 minutes of intervals. They ingested supplements immediately postexercise and 2 hours into a 4-hour recovery. Biopsies were performed at recovery minutes 0, 45, and 240 (R0, R45, REnd). Postrecovery, subjects performed a 40-km time trial (TT). The TT time was faster in CM than in CHO and in PLA (79.43 ± 2.11 vs. 85.74 ± 3.44 and 86.92 ± 3.28 minutes, p ≤ 0.05). Muscle glycogen resynthesis was higher in CM and in CHO than in PLA (23.58 and 30.58 vs. 7.05 μmol·g−1 wet weight, p ≤ 0.05). The mammalian target of rapamycin phosphorylation was greater at R45 in CM than in CHO or in PLA (174.4 ± 36.3 vs. 131.3 ± 28.1 and 73.7 ± 7.8% standard, p ≤ 0.05) and at REnd in CM than in PLA (94.5 ± 9.9 vs. 69.1 ± 3.8%, p ≤ 0.05). rpS6 phosphorylation was greater in CM than in PLA at R45 (41.0 ± 8.3 vs. 15.3 ± 2.9%, p ≤ 0.05) and REnd (16.8 ± 2.8 vs. 8.4 ± 1.9%, p ≤ 0.05). FOXO3A phosphorylation was greater at R45 in CM and in CHO than in PLA (84.7 ± 6.7 and 85.4 ± 4.7 vs. 69.2 ± 5.5%, p ≤ 0.05). These results indicate that postexercise CM supplementation can improve subsequent exercise performance and provide a greater intracellular signaling stimulus for PRO synthesis compared to CHO and placebo.
PITKÄNEN, H. T., T. NYKÄNEN, J. KNUUTINEN, K. LAHTI, O. KEINÄNEN, M. ALEN, P. V. KOMI, and A. A. MERO. Free Amino Acid Pool and Muscle Protein Balance after Resistance Exercise. Med. Sci. Sports Exerc., Vol. 35, No. 5, pp. 784-792, 2003.
Purpose: The aim of this study was to assess the effects of a resistance exercise session (RES) on free amino acid concentrations and protein synthesis and breakdown of the vastus lateralis (VL) muscle during recovery in male subjects.
Methods: Both the exercise group (EG) and the control group (CG) consisted of six healthy physically active men. On the experiment day in fasting conditions, a stable isotopic tracer of L-[ring-2H5] phenylalanine was infused and EG started a heavy 50-min hypertrophic RES for lower extremities after 55 min of infusion. At the same time, CG was at rest. During recovery of 195 min after RES, several blood samples were drawn from the femoral artery (FA) and the femoral vein (FV) and muscle samples from the VL muscle. The enrichment was analyzed by GC/MS and leg muscle amino acid kinetics determined by three-pool compartment model between FA, FV, and VL.
Results: During recovery at 60 min after RES, there was no difference in muscle protein synthesis or muscle protein breakdown between the groups, but at 195 min, both muscle protein synthesis (P < 0.05) and muscle protein breakdown (P < 0.05) were increased in EG compared with CG. The protein net balance was negative and similar in both groups. Simultaneously in serum concentrations, there was a decrease in leucine (P < 0.05) associated with an increase in aspartate (P < 0.05). Furthermore, the exercise-induced increase in alanine concentration decreased both in serum and muscle.
Conclusion: In fasting conditions, protein net balance is negative and RES induces an increase in muscle protein synthesis and breakdown at 195 min but not yet at 60 min of recovery.
As a response to physical stress, amino acids are mobilized from the body's free amino acid pool (19), which is located in the plasma and in cellular spaces (28). The pool represents only 2% (approximately 200 g) of the total amino acids in the body of a 70-kg individual, and approximately half of it (approximately 100 g) exists intracellularly in skeletal muscle (28). Despite the small size of the pool, it accounts for several metabolic reactions and protein turnover (28). Some of the amino acids are used for protein synthesis, some for energy requirement of muscular activity through oxidation, and some provide substrates for gluconeogenesis (21). Exercise induces changes both in free amino acid concentrations and in protein metabolism, and these responses have been shown to be both acute and long term, lasting from several minutes to as long as several days (10). During recovery after exercise, the use of the amino acid pool is variable. The utilization of free amino acids in energy processes decreases, and their use in anabolic processes increases. Homeostatic equilibrium is restored, energy recourses are replenished, and anabolic functions are accomplished (26).
Previous studies have reported different responses in free amino acid concentrations and in muscle protein metabolism, depending on the type of exercise. Aerobic type exercise has been shown to induce marked changes in plasma and in muscle amino acid concentrations as well as in protein synthesis (4,15). Alanine output from muscle decreases rapidly after the end of exercise, thus decreasing the blood level of alanine (7,29). Carraro et al. (5) reported total intracellular free amino acid concentration to be elevated after prolonged aerobic exercise, despite the increased efflux of alanine from muscle. They also demonstrated the increase of 25% in muscle protein synthesis after walking 4 h on a treadmill (5).
The response of postexercise muscle protein metabolism to aerobic exercise differs from the response to resistance exercise. After a strength exercise session, decreases both in serum levels of EAA and total amino acids have been observed, whereas alanine, taurine, and citrulline were unchanged (18). Muscle protein synthesis has been shown to be stimulated by resistance exercise as long as the intensity of exercise is enough to challenge the muscles, but training status may play a role in the response (6,8,17,24). Muscle protein breakdown is also increased after resistance exercise but not as much as protein synthesis (2,17). The relationship between these two parameters (rate of muscle protein synthesis and muscle protein breakdown) represents the metabolic basis for muscle growth; muscle hypertrophy occurs only when a positive protein balance can be established during the recovery through an increase in protein synthesis in the excess of the elevation in protein breakdown (2). In the study of Tipton et al. (22), the responses of muscle protein metabolism were examined after the combination of endurance and resistance exercise in swimmers. The authors concluded that the combination of exercise workout provided a stimulatory effect of muscle protein synthesis but not on whole-body tissue breakdown (22).
Several studies have examined the response of muscle protein metabolism to exercise, but the data have been collected primarily in response to endurance exercise. To our knowledge, research in the area of resistance exercise and its effects on amino acid concentrations and on net muscle protein balance simultaneously is limited. Studies to date have not addressed the potential relationship between the arteriovenous (a-v) and intracellular concentrations of amino acids and muscle protein kinetics after resistance exercise. The role of plasma and muscle amino acid concentrations in the early recovery is interesting, as amino acid availability plays an important role in the control of muscle protein kinetics. Increased blood flow, increased amino acid delivery to the muscle, and increased amino acid transport increase the rate of muscle protein synthesis (1,2,23) up to 24 h (4). In our earlier study, we have concentrated on the changes in serum amino acid concentrations during different kinds of anaerobic exercise, and decreases were demonstrated in the levels of several amino acids after running and strength exercise sessions (18). In the present study, we aimed to quantify the amino acid concentrations during the first 3 h of recovery. We chose the resistance exercise session on the basis of our previous results, as the observed decreases in all amino acid concentrations were greater in strength exercise session than in running exercise sessions. In addition, it has been shown (2) that resistance exercise has a profound effect both on muscle protein synthesis and muscle protein breakdown.
Therefore, the purpose of this study was to determine the amino acid profile in arterial and venous blood and in vastus lateralis (VL) muscle after a resistance exercise session (RES) in physically active males. We aimed also to assess whether a RES can induce changes in protein kinetics of VL muscle during recovery by using a three-compartment model (1).
The role of nutrition in modulating postexercise overnight recovery remains to be elucidated. We assessed the effect of protein ingestion immediately before sleep on digestion and absorption kinetics and protein metabolism during overnight recovery from a single bout of resistance-type exercise.
Sixteen healthy young males performed a single bout of resistance-type exercise in the evening (2000 h) after a full day of dietary standardization. All subjects were provided with appropriate recovery nutrition (20 g of protein, 60 g of CHO) immediately after exercise (2100 h). Thereafter, 30 min before sleep (2330 h), subjects ingested a beverage with (PRO) or without (PLA) 40 g of specifically produced intrinsically [1-C]phenylalanine-labeled casein protein. Continuous intravenous infusions with [ring-H5]phenylalanine and [ring-H2]tyrosine were applied with blood and muscle samples collected to assess protein digestion and absorption kinetics, whole-body protein balance and mixed muscle protein synthesis rates throughout the night (7.5 h).
During sleep, casein protein was effectively digested and absorbed resulting in a rapid rise in circulating amino acid levels, which were sustained throughout the remainder of the night. Protein ingestion before sleep increased whole-body protein synthesis rates (311 ± 8 vs 246 ± 9 μmol·kg per 7.5 h) and improved net protein balance (61 ± 5 vs -11 ± 6 μmol·kg per 7.5 h) in the PRO vs the PLA experiment (P < 0.01). Mixed muscle protein synthesis rates were ∼22% higher in the PRO vs the PLA experiment, which reached borderline significance (0.059%·h ± 0.005%·h vs 0.048%·h ± 0.004%·h, P = 0.05).
This is the first study to show that protein ingested immediately before sleep is effectively digested and absorbed, thereby stimulating muscle protein synthesis and improving whole-body protein balance during postexercise overnight recovery.
This study examined effects of fat-free chocolate milk (MILK) consumption on kinetic and cellular markers of protein turnover, muscle glycogen, and performance during recovery from endurance exercise.
Male runners participated in two trials separated by 1 wk and consumed either MILK or a nonnitrogenous isocaloric carbohydrate (CHO) control beverage (CON) after a 45-min run at 65% of V˙O(2peak). Postexercise muscle protein fractional synthetic rate (FSR) and whole-body protein turnover were determined during 3 h of recovery using muscle biopsies and primed constant infusions of L-[ring-²H₅]phenylalanine and L-[1-¹³C]leucine, respectively. Phosphorylation of translational signaling proteins and activity of proteolytic molecules were determined using Western blotting and enzymatic activity assays. Muscle glycogen was quantified, and treadmill time to exhaustion was determined after the recovery period.
Consuming MILK after exercise resulted in higher mixed muscle FSR with lower whole-body proteolysis and synthesis compared with CON (P ≤ 0.05). Phosphorylation of eIF4E-BP1 and FOXO3a was higher for MILK (P < 0.01), whereas Akt phosphorylation was lower during recovery regardless of dietary treatment (P < 0.05). Enzymatic activity assays indicated lower caspase-3 activity during recovery for MILK (P < 0.01) and higher 26S proteasome activity for CON (P < 0.01). Muscle glycogen was not affected by either dietary treatment; however, time to exhaustion was greater for MILK than for CON (P < 0.05).
The effects of consumption of MILK after endurance exercise on FSR, signaling molecules of skeletal muscle protein turnover, leucine kinetics, and performance measures suggest unique benefits of milk compared with a CHO-only beverage.
Skeletal muscle protein synthesis (MPS) is regulated by a number of dietary factors, to include essential amino acids (EAAs). Leucine, a branched-chain amino acid, has been identified as a stimulator of MPS in many cell culture and animal studies. However, whether supplemental leucine exerts a unique stimulatory effect, as compared to other EAAs, on muscle anabolism in humans has not been clearly demonstrated. A recent study found no improvement in resting MPS in adults who consumed a 10 g EAA supplement providing added leucine (3.5 g leucine) when compared to a control 10 g EAA supplement (1.8 g leucine). These findings suggest that added leucine is unnecessary for the stimulation of MPS when sufficient EAAs are provided; however, the study of supplemental leucine during conditions such as endurance exercise, caloric deprivation, and ageing may be warranted.
Non-technical summary A single bout of exercise stimulates the production of new muscle proteins. Furthermore, ingesting protein in close proximity to exercise enhances the metabolic response. Long-term exercise training promotes muscle adaptation, and the mode of exercise performed determines the type of proteins that are made. To date, the types of proteins that are made when protein is ingested after endurance exercise are not known. We report that when well-trained male cyclists ingest protein with a carbohydrate drink after a high-intensity ride, production of proteins responsible for muscle contraction is increased. Proteins responsible for aerobic energy production are not responsive to protein feeding. Furthermore, specific signals within the muscle that control protein synthesis are responsive to protein ingestion, providing a potential mechanism to underpin our primary findings. These results suggest that protein feeding after intense endurance exercise may be important in maintaining the structural quality and power generating capacity of the muscle.
It is well documented that athletes report greater dietary supplement (DS) usage than nonathletes; however, limited data exist for Canadian athletes, especially relative to competitive performance levels.
This descriptive and analytical, cross-sectional research investigated DS practices and opinions, preferred means for DS education, and antidoping opinions among elite Canadian athletes competing at various performance levels.
Subjects completed a validated questionnaire by recall. Combined, 582 high-performance athletes (314 M, 268 F) between the ages of 11 and 42 yr (mean 19.96 +/- 3.91 yr) and representing 27 sports activities participated. Respondents were categorized into five competitive performance levels: provincial (68), national (101), North America (61), international or professional (89), and varsity (263).
Overall, most (88.4%) reported taking one or more DS during the previous 6 months (mean 3.08 +/- 1.87 DS per user). From a total of 1555 DS declared, sport drinks (22.4%), sport bars (14.0%), multivitamins and minerals (13.5%), protein supplements (9.0%), and vitamin C (6.4%) were most frequently reported. Athletes at the highest performance level were significantly more likely to use protein supplements, to be advised by strength trainers regarding DS usage, to have a higher self-rating of their diet, to prefer individual interviews for DS educational purposes, to perceive greater awareness of antidoping legislation, and train more h.wk(-1). Furthermore, differences were observed for the types of DS reported and justifications for use.
This dataset, the first of its kind in Canada, was generated with a validated and reliable questionnaire and has the potential to be extended nationally and internationally to provide greater insight into the patterns and opinions of elite athletes regarding supplementation and antidoping.
This study aimed to determine the effect of postexercise protein-leucine coingestion with CHO-lipid on subsequent high-intensity endurance performance and to investigate candidate mechanisms using stable isotope methods and metabolomics.
In this double-blind, randomized, crossover study, 12 male cyclists ingested a leucine/protein/CHO/fat supplement (LEUPRO 7.5/20/89/22 g · h(-1), respectively) or isocaloric CHO/fat control (119/22 g · h(-1)) 1-3 h after exercise during a 6-d training block (intense intervals, recovery, repeated-sprint performance rides). Daily protein intake was clamped at 1.9 g · kg(-1) · d(-1) (LEUPRO) and 1.5 g · kg(-1) · d(-1) (control). Stable isotope infusions (1-(13)C-leucine and 6,6-(2)H2-glucose), mass spectrometry-based metabolomics, and nitrogen balance methods were used to determine the effects of LEUPRO on whole-body branched-chain amino acid (BCAA) and glucose metabolism and protein turnover.
After exercise, LEUPRO increased BCAA levels in plasma (2.6-fold; 90% confidence limits = ×/÷ 1.1) and urine (2.8-fold; ×/÷ 1.2) and increased products of BCAA metabolism plasma acylcarnitine C5 (3.0-fold; ×/÷ 0.9) and urinary leucine (3.6-fold; ×/÷ 1.3) and β-aminoisobutyrate (3.4-fold; ×/÷ 1.4), indicating that ingesting ~10 g leucine per hour during recovery exceeds the capacity to metabolize BCAA. Furthermore, LEUPRO increased leucine oxidation (5.6-fold; ×/÷ 1.1) and nonoxidative disposal (4.8-fold; ×/÷ 1.1) and left leucine balance positive relative to control. With the exception of day 1 (LEUPRO = 17 ± 20 mg N · kg(-1), control = -90 ± 44 mg N · kg(-1)), subsequent (days 2-5) nitrogen balance was positive for both conditions (LEUPRO = 130 ± 110 mg N · kg(-1), control = 111 ± 86 mg N · kg(-1)). Compared with control feeding, LEUPRO lowered the serum creatine kinase concentration by 21%-25% (90% confidence limits = ± 14%), but the effect on sprint power was trivial (day 4 = 0.4% ± 1.0%, day 6 = -0.3% ± 1.0%).
Postexercise protein-leucine supplementation saturates BCAA metabolism and attenuates tissue damage, but effects on subsequent intense endurance performance may be inconsequential under conditions of positive daily nitrogen balance.
This study aimed to investigate the effect of protein ingestion on leg protein turnover and vastus lateralis muscle protein synthesis during bicycle exercise and recovery.
Eight healthy males participated in two experiments in which they ingested either a carbohydrate solution (CHO) providing 0.49 g·kg(-1)·h(-1), or a carbohydrate and protein solution (CHO + P) providing 0.49 and 0.16 g·kg(-1)·h(-1), during 3 h of bicycle exercise and 3 h of recovery. Leg protein turnover was determined from stable isotope infusion (l-[ring-C6]phenylalanine), femoral-arterial venous blood sampling, and blood flow measurements. Muscle protein synthesis was calculated from the incorporation of l-[ring-C6]phenylalanine into protein.
Consuming protein during exercise increased leg protein synthesis and decreased net leg protein breakdown; however, protein ingestion did not increase protein synthesis within the highly active vastus lateralis muscle (0.029%·h(-1), ± 0.004%·h(-1), and 0.030%·h(-1), ± 0.003%·h(-1), in CHO and CHO + P, respectively; P = 0.88). In contrast, consuming protein, during exercise and recovery, increased postexercise vastus lateralis muscle protein synthesis by 51% ± 22% (0.070%·h(-1), ± 0.003%·h(-1), and 0.105%·h(-1), ± 0.013%·h(-1), in CHO and CHO+P, respectively; P < 0.01). Furthermore, leg protein net balance was negative during recovery with CHO intake, whereas positive leg protein net balance was achieved with CHO+P intake.
We conclude that consuming protein during prolonged bicycle exercise does not increase protein synthesis within highly active leg muscles. However, protein intake may have stimulated protein synthesis within less active leg muscles and/or other nonmuscle leg tissue. Finally, protein supplementation, during exercise and recovery, enhanced postexercise muscle protein synthesis and resulted in positive leg protein net balance.
MicroRNAs (miRNA), small noncoding RNA molecules, may regulate protein synthesis, while resistance exercise training (RT) is an efficient strategy for stimulating muscle protein synthesis in vivo. However, RT increases muscle mass, with a very wide range of effectiveness in humans. We therefore determined the expression level of 21 abundant miRNAs to determine whether variation in these miRNAs was able to explain the variation in RT-induced gains in muscle mass. Vastus lateralis biopsies were obtained from the top and bottom ∼20% of responders from 56 young men who undertook a 5 day/wk RT program for 12 wk. Training-induced muscle mass gain was determined by dual-energy X-ray absorptiometry, and fiber size was evaluated by histochemistry. The expression level of each miRNA was quantified using TaqMan-based quantitative PCR, with the analysis carried out in a blinded manner. Gene ontology and target gene profiling were used to predict the potential biological implications. Of the 21 mature miRNAs examined, 17 were stable during RT in both groups. However, miR-378, miR-29a, miR-26a, and miR-451 were differentially expressed between low and high responders. miR-378, miR-29a, and miR-26a were downregulated in low responders and unchanged in high responders, while miR-451 was upregulated only in low responders. Interestingly, the training-induced change in miR-378 abundance was positively correlated with muscle mass gains in vivo. Gene ontology analysis of the target gene list of miR-378, miR-29a, miR-26a, and miR-451, from the weighted cumulative context ranking methodology, indicated that miRNA changes in the low responders may be compensatory, reflecting a failure to "activate" growth and remodeling genes. We report, for the first time, that RT-induced hypertrophy in human skeletal muscle is associated with selected changes in miRNA abundance. Our analysis indicates that miRNAs may play a role in the phenotypic change and pronounced intergroup variation in the RT response.
The purpose of the present study was to examine the effect of increased protein intake on short-term decrements in endurance performance during a block of high-intensity training.
Trained male cyclists (VO(2max) = 64.2 ± 6.5 mL·kg(-1)·min(-1)) completed two 3-wk trials both divided equally into normal (NOR), intensified (INT), and recovery (REC) training. In a counterbalanced crossover experimental design, cyclists received either a high-protein (PRO; 3 g protein·kg(-1) body mass (BM)·d(-1)) or a normal diet (CON; 1.5 g protein·kg(-1) BM·d(-1)) during INT and REC. Dietary carbohydrate content remained constant at 6 g·kg(-1) BM·d(-1). Energy balance was maintained during each training week. Endurance performance was assessed with a VO(2max) test and a preloaded time trial. Alterations in blood metabolite responses to exercise were measured at rest, during, and after exercise. Cyclists completed the Daily Analysis of Life Demands for Athletes (DALDA) questionnaire each day.
Increased dietary protein intake led to a possible attenuation (4.3%; 90% confidence limits ×/÷5.4%) in the decrement in time trial performance after a block of high-intensity training compared with NOR (PRO = 2639 ± 350 s; CON = 2555 ± 313 s). Restoration of endurance performance during recovery training possibly benefited (2.0%; ×/÷4.9%) from additional protein intake. Frequency of symptoms of stress described as "worse than normal" reported after a block of high-intensity training was very likely (97%) attenuated (17; ±11 AUC of "a" scores part B, DALDA for INT + REC) by increasing the protein content of the diet. No discernable changes in blood metabolite concentrations were observed in PRO.
Additional protein intake reduced symptoms of psychological stress and may result in a worthwhile amelioration of the performance decline experienced during a block of high-intensity training.
The aim of this study was to determine whether adding protein to a CHO beverage would improve late-exercise cycle time-trial performance over CHO alone. Furthermore, we examined the effects of coingesting protein with CHO during exercise on postexercise markers of sarcolemmal disruption and the recovery of muscle function.
In a double-blind, crossover design, 12 trained male cyclists performed 120 min of steady-state (SS) cycling at approximately 55% VO2max followed by a time trial lasting approximately 1 h. At 15-min intervals during SS exercise, participants consumed either a CHO or a CHO + protein (CHO + Pro) beverage (providing 65 g x h(-1) CHO or 65 g x h(-1) CHO plus 19 g x h(-1) protein). Twenty-four hours after the onset of the SS cycle, participants completed a maximum isometric strength test. At rest and 24 h postexercise, a visual analog scale was used to determine lower-limb muscle soreness, and blood samples were obtained for plasma creatine kinase concentration. Dietary control was implemented 24 h before and during the time course of each trial.
Average power output sustained during time trial was similar for CHO and CHO + Pro, with no effect of treatment on the time to complete the time trial (60:13 +/- 1:33 and 60:51 +/- 2:40 (min:s) for CHO and CHO + Pro, respectively). Postexercise isometric strength significantly declined for CHO (15% +/- 3%) and CHO + Pro (11% +/- 3%) compared with baseline (486 +/- 28 N). Plasma creatine kinase concentrations, and visual analog scale soreness significantly increased at 24 h postexercise, with no difference between treatments.
The present findings suggest that CHO + Pro coingestion during exercise does not improve late-exercise time-trial performance, ameliorate markers of sarcolemmal disruption, or enhance the recovery of muscle function at 24 h postexercise over CHO alone.
The purpose of this study was to examine the role of branched-chain amino acid (BCAA) supplementation during recovery from intense eccentric exercise.
Twenty-four non-weight-trained males were assigned to one of two groups: one group (supplementary, SUP) ingested BCAA beverages (n = 12); the second group (placebo, PLA) ingested artificially flavored water (n = 12). Diet was controlled throughout the testing period to match habitual intake. The eccentric exercise protocol consisted of 12 x 10 repetitions of unilateral eccentric knee extension exercise at 120% concentric one repetition maximum. On the day of the exercise, supplements were consumed 30 min before exercise, 1.5 h after exercise, between lunch and dinner, and before bed. On the following 2 d, four supplements were consumed between meals. Muscle soreness, muscle function, and putative blood markers of muscle damage were assessed before and after (1, 8, 24, 48, and 72 h) exercise.
Muscle function decreased after the eccentric exercise (P < 0.0001), but the degree of force loss was unaffected by BCAA ingestion (51% +/- 3% with SUP vs -48% +/- 7% with PLA). A decrease in flexed muscle soreness was observed in SUP compared with PLA at 48 h (21 +/- 3 mm vs 32 +/- 3 mm, P = 0.02) and 72 h (17 +/- 3 mm vs 27 +/- 4 mm, P = 0.038). Flexed muscle soreness, expressed as area under the curve, was lower in SUP than in PLA (P = 0.024).
BCAA supplementation may attenuate muscle soreness, but it does not ameliorate eccentric exercise-induced decrements in muscle function or increases in reputed blood markers of muscle damage, when consumed before exercise and for 3 d after an eccentric exercise bout.
Ingesting protein (PRO) with CHO during prolonged exercise is purported to improve performance compared with CHO alone by altering the regulation of skeletal muscle energy provision. However, no study has directly investigated this issue. We tested the hypothesis that compared with CHO alone, coingestion of PRO would alter markers of metabolic control, including the magnitude of glycogen use and the net expansion of the tricarboxylic acid cycle intermediate pool, which has been linked to the capacity for oxidative energy delivery.
Eight trained men (mean +/- SE: age = 29 +/- 2 yr; VO2peak = 55 +/- 2 mL x kg(-1) x min(-1)) cycled at 69% +/- 1% VO2peak for 90 min on two occasions, and biopsy samples (vastus lateralis) were obtained before and after exercise. In a randomized, double-blind manner, subjects ingested one of two drinks during exercise that contained either 6% CHO or 6% CHO + 2% PRO (CHO + PRO) at a rate of 1 L x h(-1) to deliver 60 g x h(-1) CHO +/- 20 g x h(-1) PRO.
CHO + PRO ingestion increased the plasma concentration of branched chain (561 +/- 46 vs 301 +/- 32 micromol x L(-1)) and essential amino acids (1071 +/- 98 vs 670 +/- 71 micromol x L(-1)) after exercise versus CHO (both P values <or=0.05). However, net muscle glycogen use (CHO + PRO = 223 +/- 31 vs CHO = 185 +/- 38 mmol x kg(-1) dry weight) and tricarboxylic acid cycle intermediate expansion (CHO + PRO = 2.3 +/- 0.7 vs CHO = 2.1 +/- 0.2 mmol x kg(-1) dry weight) were similar between trials. Blood creatine kinase activity and 20-km time trial performance measured approximately 24 h after the first exercise bout were not different between treatments.
When trained men ingest CHO at a rate on the upper end of the range generally recommended to improve endurance performance, coingestion of PRO does not alter specific markers proposed to reflect an enhanced capacity for skeletal muscle energy delivery.
This study was designed to compare the acute response of mixed muscle protein synthesis (MPS) to rapidly (i.e., whey hydrolysate and soy) and slowly (i.e., micellar casein) digested proteins both at rest and after resistance exercise. Three groups of healthy young men (n = 6 per group) performed a bout of unilateral leg resistance exercise followed by the consumption of a drink containing an equivalent content of essential amino acids (10 g) as either whey hydrolysate, micellar casein, or soy protein isolate. Mixed MPS was determined by a primed constant infusion of l-[ring-(13)C(6)]phenylalanine. Ingestion of whey protein resulted in a larger increase in blood essential amino acid, branched-chain amino acid, and leucine concentrations than either casein or soy (P < 0.05). Mixed MPS at rest (determined in the nonexercised leg) was higher with ingestion of faster proteins (whey = 0.091 +/- 0.015, soy = 0.078 +/- 0.014, casein = 0.047 +/- 0.008%/h); MPS after consumption of whey was approximately 93% greater than casein (P < 0.01) and approximately 18% greater than soy (P = 0.067). A similar result was observed after exercise (whey > soy > casein); MPS following whey consumption was approximately 122% greater than casein (P < 0.01) and 31% greater than soy (P < 0.05). MPS was also greater with soy consumption at rest (64%) and following resistance exercise (69%) compared with casein (both P < 0.01). We conclude that the feeding-induced simulation of MPS in young men is greater after whey hydrolysate or soy protein consumption than casein both at rest and after resistance exercise; moreover, despite both being fast proteins, whey hydrolysate stimulated MPS to a greater degree than soy after resistance exercise. These differences may be related to how quickly the proteins are digested (i.e., fast vs. slow) or possibly to small differences in leucine content of each protein.
Statistical guidelines and expert statements are now available to assist in the analysis and reporting of studies in some biomedical disciplines. We present here a more progressive resource for sample-based studies, meta-analyses, and case studies in sports medicine and exercise science. We offer forthright advice on the following controversial or novel issues: using precision of estimation for inferences about population effects in preference to null-hypothesis testing, which is inadequate for assessing clinical or practical importance; justifying sample size via acceptable precision or confidence for clinical decisions rather than via adequate power for statistical significance; showing SD rather than SEM, to better communicate the magnitude of differences in means and nonuniformity of error; avoiding purely nonparametric analyses, which cannot provide inferences about magnitude and are unnecessary; using regression statistics in validity studies, in preference to the impractical and biased limits of agreement; making greater use of qualitative methods to enrich sample-based quantitative projects; and seeking ethics approval for public access to the depersonalized raw data of a study, to address the need for more scrutiny of research and better meta-analyses. Advice on less contentious issues includes the following: using covariates in linear models to adjust for confounders, to account for individual differences, and to identify potential mechanisms of an effect; using log transformation to deal with nonuniformity of effects and error; identifying and deleting outliers; presenting descriptive, effect, and inferential statistics in appropriate formats; and contending with bias arising from problems with sampling, assignment, blinding, measurement error, and researchers' prejudices. This article should advance the field by stimulating debate, promoting innovative approaches, and serving as a useful checklist for authors, reviewers, and editors.
We examined the impact of an acute bout of resistance-type exercise on mixed muscle protein synthesis in the fed state.
After a standardized breakfast, 10 untrained males completed a single, unilateral lower-limb resistance-type exercise session. A primed, continuous infusion of l-[ring-C6]phenylalanine was combined with muscle biopsy collection from both the exercised (Ex) and the nonexercised (NEx) leg to assess the impact of local muscle contractions on muscle protein synthesis rates after food intake. Western blotting with phosphospecific and pan antibodies was used to determine the phosphorylation status of AMP-activated kinase (AMPK), 4E-binding protein (4E-BP1), mammalian target of rapamycin (mTOR), and p70 ribosomal protein S6 kinase (S6K1).
Muscle protein synthesis rates were approximately 20% higher in Ex compared with NEx (0.098% +/- 0.005% vs 0.083% +/- 0.002%.h, respectively, P < 0.01). In the fed state, resistance-type exercise did not elevate AMPK phosphorylation. However, the phosphorylation status of 4E-BP1 was approximately 20% lower after cessation of exercise in Ex compared with NEx (P < 0.05). Conversely, 4E-BP1 phosphorylation was significantly higher in Ex compared with NEx after 6 h of recovery (P < 0.05) with no changes in mTOR phosphorylation. S6 phosphorylation was greater in Ex versus NEx after cessation of exercise (P < 0.05), although S6K1 phosphorylation at T was not up-regulated (P > 0.05).
We conclude that resistance-type exercise performed in a fed state further elevates postprandial muscle protein synthesis rates, which is accompanied by an increase in S6 and 4E-BP1 phosphorylation state.
Coingestion of protein with carbohydrate (CHO) during recovery from exercise can affect muscle glycogen synthesis, particularly if CHO intake is suboptimal. Another potential benefit of protein feeding is an increased synthesis rate of muscle proteins, as is well documented after resistance exercise. In contrast, the effect of nutrient manipulation on muscle protein kinetics after aerobic exercise remains largely unexplored. We tested the hypothesis that ingesting protein with CHO after a standardized 2-h bout of cycle exercise would increase mixed muscle fractional synthetic rate (FSR) and whole body net protein balance (WBNB) vs. trials matched for total CHO or total energy intake. We also examined whether postexercise glycogen synthesis could be enhanced by adding protein or additional CHO to a feeding protocol that provided 1.2 g CHO·kg-1·h-1, which is the rate generally recommended to maximize this process. Six active men ingested drinks during the first 3 h of recovery that provided either 1.2 g CHO·kg-1·h-1 (L-CHO), 1.2 g CHO + 0.4 g protein·kg-1·h-1 (PROCHO), or 1.6 g CHO·kg-1·h-1 (H-CHO) in random order. Based on a primed constant infusion of L-[ring-2H5] phenylalanine, analysis of biopsies (vastus lateralis) obtained at 0 and 4 h of recovery showed that muscle FSR was higher (P < 0.05) in PRO-CHO (0.09 ± 0.01%/h) vs. both L-CHO (0.07 ± 0.01%/h) and H-CHO (0.06 ± 0.01%/h). WBNB assessed using [1-13C]leucine was positive only during PRO-CHO, and this was mainly attributable to a reduced rate of protein breakdown. Glycogen synthesis rate was not different between trials. We conclude that ingesting protein with CHO during recovery from aerobic exercise increased muscle FSR and improved WBNB, compared with feeding strategies that provided CHO only and were matched for total CHO or total energy intake. However, adding protein or additional CHO to a feeding strategy that provided 1.2 g CHO·kg-1·h-1 did not further enhance glycogen resynthesis during recovery.
This study examined the effect of amino acids in a carbohydrate beverage on cycling performance. Twelve male athletes (28.5 +/- 2.1 yr) cycled at 75% VO2peak for 90 min followed by a ride to exhaustion at 85% VO2peak, before (T1) and on 2 consecutive days (T2 and T3) after 2 weeks of supplementation with 3.6% carbohydrate plus 1% amino acids (AA) or 4.6% carbohydrate-only (CHO) isocaloric beverages. Muscle damage was assessed by plasma creatine kinase (CK), and muscle fatigue by changes in vertical jump pre- to postexercise. Muscle soreness, overall fatigue, and changes in mood state were assessed using questionnaires. Plasma CK was lower for AA in T3 (214.0 +/- 13.5 vs. 485.9 +/- 191.4 U/L immediately post, 213.9 +/- 13.1 vs. 492.0 +/- 199.4 U/L 5 hr post, and 194.9 +/- 17.9 vs. 405.9 +/- 166.6 U/L 24 hr postexercise in AA and CHO, respectively). Time to exhaustion decreased from T2 to T3 only in CHO (10.9 +/- 2.5 to 12.6 +/- 3.2 vs. 13.8 +/- 2.8 to 7.8 +/- 1.5 min in AA and CHO, respectively). Vertical-jump change from pre- to postexercise was greater in T3 for the CHO treatment. Total fatigue score and mood disturbance decreased significantly only with AA in T3. The addition of AA to a carbohydrate beverage after consecutive-day exercise bouts reduced muscle damage as indicated by CK levels, decreased fatigue, and maintained exercise performance compared with consuming carbohydrate alone.
There is evidence that protein hydrolysates can speed tissue repair following damage and may therefore be useful for accelerating recovery from exercise induced muscle damage. The potential for a hydrolysate (WPI(HD)) of whey protein isolate (WPI) to speed recovery following eccentric exercise was evaluated by assessing effects on recovery of peak isometric torque (PIT). In a double-blind randomised parallel trial, 28 sedentary males had muscle soreness (MS), serum creatine kinase (CK) activity, plasma TNFalpha, and PIT assessed at baseline and after 100 maximal eccentric contractions (ECC) of their knee extensors. Participants then consumed 250 ml of flavoured water (FW; n=11), or FW containing 25 g WPI (n=11) or 25 g WPI(HD) (n=6) and the assessments were repeated 1, 2, 6 and 24h later. PIT decreased approximately 23% following ECC, remained suppressed in FW and WPI, but recovered fully in WPI(HD) by 6h (P=0.006, treatment x time interaction). MS increased following ECC (P<0.001 for time), and remained elevated with no difference between groups (P=0.61). TNFalpha and CK did not change (P>0.45). WPI(HD) may be a useful supplement for assisting athletes to recover from fatiguing eccentric exercise.
Unlabelled:
Carbohydrate-protein (CHO+Pro) beverages reportedly improve endurance and indices of muscle disruption, but it is unclear whether these effects are related to total energy intake or specific effects of protein.
Purpose:
The authors examined effects of CHO+Pro on time to exhaustion and markers of muscle disruption compared with placebo (PLA) and carbohydrate beverages matched for carbohydrate (CHO) and total calories (CHO+CHO).
Methods:
Eleven male cyclists completed 4 rides to exhaustion at 75% VO2peak. Participants consumed 250 ml of PLA, CHO (7.75%), CHO+CHO (9.69%), or CHO+Pro (7.75%/1.94%) every 15 min until fatigue, in a double-blind design.
Results:
Time to exhaustion was significantly longer (p<.05) in CHO+Pro (126.2+/-25.4 min) and CHO+CHO (121.3+/-36.8) than PLA (107.1+/-30.3). CHO (117.5+/-24.2) and PLA were not significantly different. Similarly, CHO+Pro was not significantly different from CHO and CHO+CHO. Postexercise plasma creatine kinase was lower after CHO+Pro (197.2+/-149.2 IU/L) than PLA (407.4+/-391.3), CHO (373.2+/-416.6), and CHO+CHO (412.3+/-410.2). Postexercise serum myoglobin was lower in CHO+Pro (47.0+/-27.4 ng/mL) than all other treatments (168.8+/-217.3, 82.6+/-71.3, and 72.0+/-75.8). Postexercise leg extensions at 70% 1RM were significantly greater 24 hr after CHO+Pro (11.3+/-4.1) than PLA (8.8+/-3.7), CHO (9.7+/-4.3), and CHO+CHO (9.5+/-3.6).
Conclusion:
These findings suggest that at least some of the reported improvements in endurance with CHO+Pro beverages might be related to caloric differences between treatments. Postexercise improvements in markers of muscle disruption with CHO+Pro ingestion appear to be independent of carbohydrate and caloric content and were elicited with beverages consumed only during exercise.
This brief review focuses on the time course of changes in muscle function and other correlates of muscle damage following maximal effort eccentric actions of the forearm flexor muscles. Data on 109 subjects are presented to describe an accurate time course of these changes and attempt to establish relationships among the measures. Peak soreness is experienced 2-3 d postexercise while peak swelling occurs 5 d postexercise. Maximal strength and the ability to fully flex the arm show the greatest decrements immediately after exercise with a linear restoration of these functions over the next 10 d. Blood creatine kinase (CK) levels increase precipitously at 2 d after exercise which is also the time when spontaneous muscle shortening is most pronounced. Whether the similarity in the time courses of some of these responses implies that they are caused by similar factors remains to be determined. Performance of one bout of eccentric exercise produces an adaptation such that the muscle is more resistant to damage from a subsequent bout of exercise. The length of the adaptation differs among the measures such that when the exercise regimens are separated by 6 wk, all measures show a reduction in response on the second, compared with the first, bout. After 10 wk, only CK and muscle shortening show a reduction in response. After 6 months only the CK response is reduced. A combination of cellular factors and neurological factors may be involved in the adaptation process.
The repeated bout effect on changes in muscle damage indicators was examined in two groups of subjects following two bouts of 70 maximal eccentric actions of the forearm flexors. Fourteen college age female subjects were placed into two groups. The two bouts were separated by 6 weeks (n = 6), and 10 weeks (n = 8). The subjects performed the same amount of work for the bouts. The muscle damage indicators were isometric strength (STR), relaxed elbow joint angle (RANG), flexed elbow joint angle (FANG), perceived muscle soreness ratings (SOR), and plasma creatine kinase activity (CK). These measures were obtained pre-exercise and 5 days following each bout. The first bout showed significant changes in all measures over time for both groups (P less than 0.01). For the 6-week group, significantly smaller changes in RANG (P less than 0.01), SOR (P less than 0.05), and CK (P less than 0.01), as well as significantly faster recoveries (P less than 0.05) for STR and FANG were produced in the second bout. For the 10-week group, significantly smaller changes in RANG (P less than 0.05) and CK (P less than 0.01) were demonstrated by the second bout, but not significant difference was found for STR, FANG, and SOR between bouts 1 and 2. Changes in CK were still significantly smaller than that of the first bout when 6 subjects (3 subjects from each group) performed the same exercise 6 months after the second bout, but no difference in other measures.(ABSTRACT TRUNCATED AT 250 WORDS)
This investigation examines the effect of progressive resistance weight training exercise on urinary 3-methylhistidine (3-MH) excretions in untrained subjects. For 19 consecutive days, 11 males were fed a weight maintenance, lactovegetarian diet which contained the Recommended Dietary Allowance (0.8g.kg-1.d-1) for protein. No exercise was performed for the first 7 d of the study. Subjects were strength tested on day 8 and performed upper and lower body weight training exercises from days 9-19. Complete, 24-h urine collections were obtained from each subject on a daily basis. Samples were assayed for creatinine and 3-MH. Stable baseline 3-MH values were present during the pre-exercise control period. Significant increases in 3-MH occurred by study day 11, which was the third day of weight training exercise. This was true regardless of whether the data were expressed by daily excretions (microM.d-1; P less than 0.01), per unit of body weight (microM.kg-1.d-1; P less than 0.005), or per unit of creatinine excretion (microM.g Creat-1.d-1; P less than 0.001). Since urinary 3-MH is an index of actin and myosin catabolism, these data support the hypothesis that the rate of skeletal muscle degradation is increased during strength building exercises.
The rates of protein synthesis and degradation and of amino acid transport were determined in the leg muscle of untrained postabsorptive normal volunteers at rest and approximately 3 h after a resistance exercise routine. The methodology involved use of stable isotopic tracers of amino acids, arteriovenous catheterization of the femoral vessels, and biopsy of the vastus lateralis muscle. During postexercise recovery, the rate of intramuscular phenylalanine utilization for protein synthesis increased above the basal value by 108 +/- 18%, whereas the rate of release from proteolysis increased by 51 +/- 17%. Muscle protein balance improved (P < 0.05) after exercise but did not become positive (from -15 +/- 12 to -6 +/- 3 nmol phenylalanine.min-1.100 ml leg volume-1). After exercise, rates of inward transport of leucine, lysine, and alanine increased (P < 0.05) above the basal state from 132 +/- 16 to 208 +/- 29, from 122 +/- 8 to 260 +/- 8, and from 384 +/- 71 to 602 +/- 89 nmol.min-1.100 ml leg-1, respectively. Transport of phenylalanine did not change significantly. These results indicate that, during recovery after resistance exercise, muscle protein turnover is increased because of an acceleration of synthesis and degradation. A postexercise acceleration of amino acid transport may contribute to the relatively greater stimulation of protein synthesis.
Six normal untrained men were studied during the intravenous infusion of a balanced amino acid mixture (approximately 0.15 g.kg-1.h-1 for 3 h) at rest and after a leg resistance exercise routine to test the influence of exercise on the regulation of muscle protein kinetics by hyperaminoacidemia. Leg muscle protein kinetics and transport of selected amino acids (alanine, phenylalanine, leucine, and lysine) were isotopically determined using a model based on arteriovenous blood samples and muscle biopsy. The intravenous amino acid infusion resulted in comparable increases in arterial amino acid concentrations at rest and after exercise, whereas leg blood flow was 64 +/- 5% greater after exercise than at rest. During hyperaminoacidemia, the increases in amino acid transport above basal were 30-100% greater after exercise than at rest. Increases in muscle protein synthesis were also greater after exercise than at rest (291 +/- 42% vs. 141 +/- 45%). Muscle protein breakdown was not significantly affected by hyperminoacidemia either at rest or after exercise. We conclude that the stimulatory effect of exogenous amino acids on muscle protein synthesis is enhanced by prior exercise, perhaps in part because of enhanced blood flow. Our results imply that protein intake immediately after exercise may be more anabolic than when ingested at some later time.