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The effects of amino acid supplementation on hormonal responses to resistance training overreaching
Abstract
The purpose of this investigation was to examine the effects of amino acid supplementation on muscular performance and resting hormone concentrations during resistance training overreaching. Seventeen resistance-trained men were randomly assigned to either an amino acid (AA) or a placebo (P) group and underwent 4 weeks of total-body resistance training designed to induce a state of overreaching. The protocol consisted of two 2-week phases (phase 1, 3 sets of 8 exercises performed for 8-12 repetitions; phase 2, 5 sets of 5 exercises performed for 3-5 repetitions). Muscle strength and resting blood samples were determined before (T1) and at the end of each training week (T2-T5). One-repetition maximum squat and bench press decreased at T2 in the P group but not in the AA group; both groups showed similar increases in strength at T3 to T5. Significant elevations in serum creatine kinase and uric acid were observed at T2 in the P group; the elevation in creatine kinase correlated highly to reductions in 1-repetition maximum squat (r = -0.67, r(2) = 0.45). Significant elevations in serum sex hormone-binding globulin were observed during overreaching in the P group from T2 to T5; this response was abolished in the AA group. Significant reductions in total testosterone were observed in the P group at T4 compared with T1, and total testosterone values were higher for the AA group than for the P group from T2 to T4. Serum 22-kd growth hormone concentrations were elevated at T2 to T5 in P group only. No differences were observed in resting cortisol and insulinlike growth factor 1. Hemoglobin concentrations were significantly reduced at T2 to T5 in the P group. These results indicate that the initial impact of high-volume resistance training is muscle strength reduction and hormonal/biochemical alterations. It appears that amino acid supplementation is effective for attenuating muscle strength loss during initial high-volume stress, possibly by reducing muscle damage by maintaining an anabolic environment.
... Studies have examined the effects of high-volume and/or highintensity RT (Berning et al., 2007;Fry et al., 2001Fry et al., , 1994cFry et al., , 1998Fry et al., , 1994bFry et al., , 1994dFry et al., , 2006Fry et al., , 2000bNicoll et al., 2016;Raastad et al., 2001;Raeder et al., 2016;Robbins et al., 2012;Sharp & Pearson, 2010;Sikorski et al., 2013;Sterczala et al., 2017;Taylor et al., 2016;Tibana et al., 2018) as well as phasic, periodized approaches to OR (Fatouros et al., 2006;Jakubowski et al., 2019;Kraemer et al., 2006;Lowery et al., 2016;Ratamess et al., 2003;Stone et al., 2000;Volek et al., 2004;Wilson et al., 2013). Overall, both short-term increased RT volume and intensity can result in FOR, but excessive exposure in terms of magnitude and/or duration can also result in NFOR -especially during prolonged high-intensity RT. ...
... Increases in C-reactive protein (CRP) and CK have been reported during periods of short-term OR (Drake et al., 2017;Fatouros et al., 2006;Sikorski et al., 2013). CK appears to be correlated with perceived recovery after a single RT session (Sikorski et al., 2013), and maximal squat strength (Kraemer et al., 2006). However, increased CRP/CK has been reported after a period of high-intensity, high-volume RT resulting in performance gain (Drake et al., 2017), and therefore may be a part of the adaptive process that underpins FOR rather than an indicator of NFOR or OTS. ...
... The effects of various supplements have been examined during purposeful OR periods, including amino acids (AA) (Kraemer et al., 2006;Ratamess et al., 2003;Sharp & Pearson, 2010), β-Hydroxy β-methylbutyric-free acid (HMB-FA) (Jakubowski et al., 2019), adenosine-5ʹ-triphosphate (ATP) , creatine monohydrate (CrM) (Volek et al., 2004), phosphatidylserine (Ps) (Fahey & Pearl, 1998) and multi-ingredient supplementation (Lowery et al., 2016;Sterczala et al., 2017). Overall, supplementation during purposeful OR may help to offset the deleterious effects of NFOR; however, some studies have observed no change. ...
To date, little is known about overreaching (OR) and the overtraining syndrome (OTS) in strength sports and resistance training (RT) populations. However, the available literature may elucidate the occurrence of both conditions in these populations. A scoping review was conducted. SPORTDiscus, Scopus and Web of Science were searched in a robust and systematic manner, with relevant articles analysed. 1170 records were retrieved during an initial search, with a total of 47 included in the review. Two broad themes were identified during data extraction: 1) overreaching in strength sports; 2) overreaching and overtraining syndrome in RT. Short-term periods of OR achieved with either high-volume or high-intensity RT can elicit functional OR (FOR) but there is also evidence that chronic high-volume and/or intensity RT can lead to non-functional overreaching (NFOR). There is minimal evidence to suggest that true OTS has occurred in strength sports or RT based on the studies entered during this review. More research is needed to develop robust guiding principles for practitioners. Additionally, due to the heterogeneous nature of the existing literature, future research would benefit from the development of practical tools to identify and diagnose the transition from FOR to NFOR, and subsequently OTS in strength athletes and RT populations.
Abbreviations
RT: Resistance training; OR: Overreaching; FOR: Functional overreaching; NFOR: Non-functional overreaching; OTS: Overtraining syndrome; WP: Weightlifting performance
... However, both the protein (mean 2.4 gÁkg -1 ) and placebo (mean 2.2 gÁkg -1 ) groups consumed high protein diets. Ratamess et al. [102], and a subsequent paper by Kraemer et al. [103], investigated the use of an amino acid supplement during 4 weeks of high-volume (10–12 ...
... The authors suggested that supplementation did not enhance performance gains since the athletes were in positive nitrogen balance at the beginning of the study and consumed high daily dietary protein ([1.6 gÁkg -1 ). 3.1.2.6 Summary: Resistance-Trained Participants An overview of the findings from the subsections on resistance-trained participants is presented in Table 3and a subsequent detailed list of the findings for protein supplements is provided in Table 4. Protein supplements had little or no effect on measures of strength and body composition when programs were 4 weeks or less [101][102][103], whereas positive effects of protein supplements have been observed on changes in lean mass and/or muscle strength when training programs were 8 weeks or longer [105][106][107][108][109][110][111]. The addition of carbohydrate to protein does not appear advantageous [106], whereas the addition of casein or Table 3An overview of the effects of protein supplementation for the different subsections reviewed for resistance-trained participants Type of study Effect of protein supplementation Note PRO versus PLA $ mass, strength (2) ...
... BCAA ? glutamine = CHO for 1 RM and # reps Kraemer et al. [103] 3repetitions, RM repetition maximum BCAA to whey protein may lead to greater gains in lean mass and strength [110, 111], but there may be a ceiling to the beneficial effect from the additional source of protein [109]. ...
Background:
Protein supplements are frequently consumed by athletes and recreationally active adults to achieve greater gains in muscle mass and strength and improve physical performance.
Objective:
This review provides a systematic and comprehensive analysis of the literature that tested the hypothesis that protein supplements accelerate gains in muscle mass and strength resulting in improvements in aerobic and anaerobic power. Evidence statements were created based on an accepted strength of recommendation taxonomy.
Data sources:
English language articles were searched through PubMed and Google Scholar using protein and supplements together with performance, exercise, strength, and muscle, alone or in combination as keywords. Additional articles were retrieved from reference lists found in these papers.
Study selection:
Studies recruiting healthy adults between 18 and 50 years of age that evaluated the effects of protein supplements alone or in combination with carbohydrate on a performance metric (e.g., one repetition maximum or isometric or isokinetic muscle strength), metrics of body composition, or measures of aerobic or anaerobic power were included in this review. The literature search identified 32 articles which incorporated test metrics that dealt exclusively with changes in muscle mass and strength, 5 articles that implemented combined resistance and aerobic training or followed participants during their normal sport training programs, and 1 article that evaluated changes in muscle oxidative enzymes and maximal aerobic power.
Study appraisal and synthesis methods:
All papers were read in detail, and examined for experimental design confounders such as dietary monitoring, history of physical training (i.e., trained and untrained), and the number of participants studied. Studies were also evaluated based on the intensity, frequency, and duration of training, the type and timing of protein supplementation, and the sensitivity of the test metrics.
Results:
For untrained individuals, consuming supplemental protein likely has no impact on lean mass and muscle strength during the initial weeks of resistance training. However, as the duration, frequency, and volume of resistance training increase, protein supplementation may promote muscle hypertrophy and enhance gains in muscle strength in both untrained and trained individuals. Evidence also suggests that protein supplementation may accelerate gains in both aerobic and anaerobic power.
Limitations:
To demonstrate measureable gains in strength and performance with exercise training and protein supplementation, many of the studies reviewed recruited untrained participants. Since skeletal muscle responses to exercise and protein supplementation differ between trained and untrained individuals, findings are not easily generalized for all consumers who may be considering the use of protein supplements.
Conclusions:
This review suggests that protein supplementation may enhance muscle mass and performance when the training stimulus is adequate (e.g., frequency, volume, duration), and dietary intake is consistent with recommendations for physically active individuals.
... Considering that heavy resistance exercise results in disruption or damage to the active muscle fibers, a greater protein intake may assist in the repair and remodeling process of these fibers (Tipton et al., 2004). A decrease in muscle damage, attenuation of force decrements , and an enhanced recovery from resistance exercise has been demonstrated in subjects using protein supplements (Kraemer et al., 2006; Ratamess et al., 2003). The combination of resistance training with a greater amino acid pool may result in a positive nitrogen balance and an increase in protein synthesis (Tarnopolsky et al., 1992; Roy et al., 1997). ...
... muscle degradation seen following bouts of resistance exercise (Tipton et al., 2004). If protein degradation is reduced with a concomitant increase in protein accretion the resulting effect would generate a greater stimulus for muscle growth and enhanced recovery, potentially resulting in greater strength gains (Kraemer et al., 2006, Ratamess et al., 2003). Studies examining the effect of protein supplementation on strength enhancement are limited and results have been inconclusive. ...
... Resting growth hormone concentrations appear to be responsive to amino acid supplementation (Bratusch- Marrain and Waldäusi, 1979), however others have reported no effect of protein supplementation on resting growth hormone or IGF-I concentrations (Kraemer et al., 2006). It does appear that changes in IGF-I concentrations are dependent upon energy intake, with caloric restriction being associated with decreases in IGF-I concentrations, while increases in caloric intake tends to elevate IGF-I (Forbes et al., 1989; Thissen et al., 1994). ...
The effect of protein supplementation on athletic performance and hormonal changes was examined in 21 experienced collegiate strength/power athletes participating in a 12-week resistance training program. Subjects were randomly assigned to either a protein supplement (PR; n = 11) or a placebo (PL; n = 10) group. During each testing session subjects were assessed for strength (one repetition maximum [1-RM] bench press and squat), power (Wingate anaerobic power test) and body composition. Resting blood samples were analyzed at weeks 0 (PRE), 6 (MID) and 12 (POST) for total testosterone, cortisol, growth hormone, and IGF-1. No difference was seen in energy intake between PR and PL (3034 ± 209 kcal and 3130 ± 266 kcal, respectively), but a significant difference in daily protein intake was seen between PR (2.00 g·kg body mass[BM]-1·d-1) and PL (1.24 g·kgBM -1·d-1). A greater change (p < 0.05) in the Δ 1-RM squat was seen in PR (23.5 ± 13.6 kg) compared to PL (9.1 ± 11.9 kg). No other significant strength or power differences were seen between the groups. Cortisol concentrations were significantly lower at MID for PL and this difference was significantly different than PR. No significant changes were noted in resting growth hormone or IGF-1 concentrations in either group. Although protein supplementation appeared to augment lower body strength development, similar upper body strength, anaerobic power and lean tissue changes do not provide clear evidence supporting the efficacy of a 12-week protein supplementation period in experienced resistance trained athletes.
... For all cases of analysis, a significance level of p < 0.05 was adopted. The indication of the sample number was based on the studies by Ratames et al. [29], Kraemer et al. [31], Sharp and Pearson [32], and Van Dusseldorp et al. [33]. ...
... It is worth mentioning that the present study used a sample number of 8 individuals, which could limit, in part, the results and conclusions presented here. However, the sample number of the experimental group of other studies carried out with the same intention [29,[31][32][33], that is, evaluating the effects of supplementation with BCAA, was like the one used here. ...
Introdução: A suplementação de aminoácidos de cadeia ramificada (BCAA) tem sido amplamente utilizada e estudada durante as atividades de longa duração, no entanto, apresenta um número restrito de estudos elucidando o efeito desta suplementação durante o treinamento resistido (TR). Objetivo: Avaliar a influência da ingestão de BCAA, contendo diferentes concentrações de leucina, sobre o número total de repetições realizadas durante essa prática. Métodos: Oito participantes (4 homens e 4 mulheres; idade: 20 a 35 anos), com experiência no TR entre 3 e 18 meses, realizaram 10 séries com carga referente a 80% de 1RM, após a ingestão de 0,4 g/kg de peso corporal de BCAA diluídos em 250 ml água, com duas diferentes concentrações de leucina: 4:1:1 (3 g leucina, 750 mg isoleucina e 750 mg valina) e 6:1:1 (4,5 g leucina, 750 mg isoleucina e 750 mg valina), além do tratamento controle (CON), caracterizado pela ingestão de 250 ml água contendo um composto dietético não calórico. Resultados: Observou-se que o número total de repetições realizadas nas 10 séries foi significativamente maior para o tratamento 6:1:1 (70,0 ± 9,5) quando comparado ao tratamento CON (59,8 ± 9,9), diferente do tratamento 4:1:1 (66,8 ± 7,3) que apresentou resultado estatisticamente semelhante. Conclusão: A concentração do aminoácido leucina, relacionada à dose de BCAA suplementada, é significativa para obtenção dos efeitos ergogênicos promovidos por este suplemento durante a prática do exercício resistido.
... These large initial increases in satellite cell numbers could reflect acute myocellular stress. In addition to direct measures of myocellular stress in muscle biopsy analyses, changes in blood concentration of creatine kinase and myoglobin, as well as changes in muscle strength, can be used as indirect markers of myocellular stress and "overreaching" (29,62). Consequently, frequent blood samples and regular measurements of muscle strength were included in this study. ...
... We hypothesized that the 10-day rest period would reset the responsiveness of the myofibers after the first 7 training sessions; however, the physiological responses were very much delayed and did not peak until 10 -20 days of detraining. The initial myofiber atrophy followed by delayed hypertrophy and strength increases are reminiscent of the supercompensation observed after periods of overreaching (29,62). It appears that the first block of unaccustomed BFRRE exceeded the capacity for recovery and may have induced muscle damage in some of our participants. ...
Abstract
PURPOSE: To investigate muscle hypertrophy, strength, myonuclear and satellite cell (SC) responses to high-frequency blood flow restricted resistance exercise (BFRRE). METHODS: Thirteen individuals (24±2 years [mean ± SD], 9 males) completed two 5-day-blocks of 7 BFRRE sessions, separated by a 10-day rest period. Four sets of unilateral knee extensions to voluntary failure at 20% of 1RM were conducted with partial blood flow restriction (90-100 mmHg). Muscle samples obtained before-, during, 3- and 10 days after training were analyzed for muscle fiber area (MFA), myonuclei, SC, and mRNA and miRNA expression. Muscle size was measured by ultrasonography and magnetic resonance imaging, and strength with 1RM knee-extension. RESULTS: With the first block of BFRRE, SC number increased in both fiber types (70-80%, p<0.05), while type I and II MFA decreased by 6±7% and 15±11% (p<0.05), respectively. With the second block of training, muscle size increased by 6-8%, while the number of SC (type I: 80±63%, type II 147±95%), myonuclei (type I: 30±24%, type II: 31±28%) and MFA (type I: 19±19%, type II: 11±19%) peaked 10 days after the second block of BFRRE, whereas strength peaked after 20 days of detraining (6±6%, p<0.05). Pax7- and p21 mRNA expression were elevated during the intervention, while myostatin, IGF1R, MyoD, myogenin, cyclinD1 and -D2 mRNA did not change until 3-10 days post intervention. CONCLUSION: High frequency low-load BFRRE induced robust increases in SC, myonuclei and muscle size, but modest strength gains. Intriguingly, the responses were delayed and peaked 10-20 days after the training intervention, indicating overreaching.
... With increases in carbohydrate and protein intake, a progressively greater anabolic response with inconstant increases in the insulin response and suppression of protein breakdown occurs [61]. However, most studies indicated that the net protein synthesis is related to the availability of amino acids [51,62,63]. The total EAA and NEAA levels showed a significant difference between the groups; the levels significantly increased in the HPRO group, even without a change in resting levels in the HCHO group. ...
... The total EAA and NEAA levels showed a significant difference between the groups; the levels significantly increased in the HPRO group, even without a change in resting levels in the HCHO group. Our results agree with previous findings that a higher protein intake stimulates MPS following resistance exercise [62], and can generate greater muscle mass and strength gains [63]. ...
Objective: Previous studies have presented the effects of carbohydrate and protein intake using a single food or supplement. However, little knowledge is available regarding the long-term effects of protein diet supplementation on muscle mass and function. This study was conducted to investigate the effects of a 12-week high-intensity resistance exercise program combined with a high-carbohydrate (HCHO), high-protein (HPRO) diet on body composition, muscle function, anabolic/catabolic hormones, and blood amino acid levels.
Methods: This study included 27 male college students, who were divided into an HPRO group (n=12) and an HCHO group (n=15). Three to five sets of resistance exercises were performed four times a week at 75% of 1- repetition maximum for 12 weeks.
Results: The weight and body fat percentage decreased in both groups after the 12-week resistance exercise, and muscle mass increased in the HPRO group. The peak torque increased in the HPRO group, and the average power increased in both the HCHO and HPRO groups, although there was no significant difference between the changes in both groups. However, the testosterone level and the ratio of testosterone to cortisol increased in the HCHO group, and the changes were significantly different between the groups. The blood essential amino acid (EAA) and non-essential amino acid levels showed a time × group effect. Conclusion: Protein supplementation of a high-carbohydrate diet during resistance training may enhance body composition and muscle mass and function by increasing the blood EAA levels. Therefore, considering that Asians tend to consume high-carbohydrate diets, a diet with slightly less carbohydrate and increased protein may be more effective for increased muscle strength and mass during training.
... Prophylactic and therapeutic nutritional interventions involving protein, protein hydrolysate, mixed amino acids, selective amino acids, and branched-chain amino acids have been demonstrated to be effective in reducing some or all of the symptoms of muscle damage following isolated eccentric muscle actions [16–18], resistance exercise [19], downhill running [20], and endurance exercise [21]. ...
... The underlying mechanism by which protein or amino acid supplementation can attenuate symptoms of muscle damage is not fully understood. Greater amino acid availability [17, 18], extra energy intake from supplementation [17], increased protein synthesis and/or decreased protein breakdown [19, 20] have been suggested as potential underlying mechanisms. ...
Purpose
L-glutamine is the most abundant amino acid found in human muscle and plays an important role in protein synthesis and can reduce the levels of inflammation biomarkers and creatine kinase (CK) after training sessions. Delayed onset muscle soreness (DOMS) develops after intense exercise and is associated with an inflammatory response. The purpose of this study was to investigate the effect of glutamine supplementation on surface electromyography activity of the vastus medialis muscle (VMM) and rectus femoris muscle (RFM) and levels of creatine kinase after an eccentric contraction.
Methods
Seventeen healthy men (age: 22.35±2.27yr; body mass: 69.91± 9.78kg; height: 177.08±4.32cm) were randomly assigned to experimental (n=9) and control groups (n=8) in a double-blind manner. In both groups, subjects were given L-glutamine supplementation (0.1g.kg-1) or placebo three times a week for 4 weeks. Median frequency (MDF) and mean power frequency (MPF) for VMM and RFM muscles and also CK measurements were performed before, 24h and 48 h after a resistance training session. The resistance training included 6 sets of eccentric leg extensions to exhaustion with 75% of 1RM.
Results
There was no significant difference between groups for MDF or MPF in VMM and RFM. The difference of CK level between the groups was also not significant.
Conclusion
The results of this study indicate that glutamine supplementation has no positive effect on muscle injury markers after a resistance training session.
... High-intensity or prolonged exercise is a potent stimulus for neuromuscular adaptations. This stimulant is essential for increasing muscle strength, overall strength, and power (Kraemer et al., 2006). Therefore, resistance exercises that stimulate muscle adaptations are of great importance for athletes and individuals who exercise for recreational aim. ...
The aim of this study is to examine the acute effect of different blood flow restriction (BFR) protocols on muscle damage. Thirty (age 19.77±1.30 years) healthy young men were included in the study. Participants were randomly divided into three groups: Experiment 1 (continuous BFR+ barbell squat, n=10), Experiment 2 (intermittent BFR + barbell squat, n=10), and Control (only barbell squats without BFR, n=10). In 80% of their 1RMs, they performed barbell squat exercises for a total of six sets, with two repetitions in each set and a 3-minute rest interval between sets. For markers of muscle damage creatine kinase (CK), lactate dehydrogenase (LDH), aspartate transaminase (AST), and alanine transaminase (ALT), blood was drawn from the individuals twice before and immediately after the exercise. Analysis of variance in repeated measures (Repeated Measures ANOVA) test was used to analyze the data. In statistical analysis, the level of significance was accepted as p
... Studies designed to investigate potential diagnostic markers of NFOR/OTS have incorporated well-controlled but varied resistance exercise OT protocols. Such studies have included both high-volume [23][24][25] and high-intensity training [18,[26][27][28][29][30][31][32][33] that have utilized either single exercise protocols (typically a variation on a squat) [18,[26][27][28][29][30][31]33] or multiple exercise training programs [23,24,32,[34][35][36][37]. To explore the mechanisms that underpin the response to OT, several of these training protocols have not been designed to improve physical performance (i.e., achieve FOR), but to induce a state of OT for the purpose of elucidating diagnostic and mechanistic information. ...
Short-term periods of increased resistance exercise training are often used by athletes to enhance performance, and can induce functional overreaching (FOR), resulting in improved physical capabilities. Non-functional overreaching (NFOR) or overtraining syndrome (OTS), occur when training demand is applied for prolonged periods without sufficient recovery. Overtraining (OT) describes the imbalance between training demand and recovery, resulting in diminished performance. While research into the effects of resistance exercise OT has gathered attention from sports scientists in recent years, the current research landscape is heterogeneous, disparate, and underrepresented in the literature. To date, no studies have determined a reliable physiological or psychological marker to assist in the early detection of NFOR or OTS following periods of resistance exercise OT. The purpose of this work is to highlight the conceptual and methodological limitations within some of the current literature, and to propose directions for future research to enhance current understanding.
... In contrast to the intuitive, instinctive approach to POR revealed by participants of this research, previous studies have used well-controlled prescriptive high-volume (Fatouros et al., 2006;Wilson et al., 2013;Lowery et al., 2016) and high-intensity (Fry et al., 1994a(Fry et al., ,c,d, 1998(Fry et al., , 2000b(Fry et al., , 2006Sharp and Pearson, 2010;Nicoll et al., 2016;Sterczala et al., 2017) resistance exercise POR protocols to investigate potential diagnostic markers of FOR and NFOR/OTS. Such protocols have incorporated either single exercise (typically the barbell back squat) (Fry et al., 1994a(Fry et al., ,c,d, 1998(Fry et al., , 2000b(Fry et al., , 2006Nicoll et al., 2016;Sterczala et al., 2017) and multiple exercises (Ratamess et al., 2003;Volek et al., 2004;Fatouros et al., 2006;Kraemer et al., 2006;Sharp and Pearson, 2010;Lowery et al., 2016;Drake et al., 2017), and both traditional strength-based exercises (squat variations, pulls and presses) and sport-specific exercises (snatch, clean and jerk, throwing drills) (Fry et al., 1993(Fry et al., , 2000aHartman et al., 2007;Bazyler et al., 2017) have been selected. Overall, the number of studies reporting either no performance maladaptation (i.e., return to baseline) or performance improvement outweigh those that have observed NFOR/OTS (Bell et al., 2020;Grandou et al., 2020b). ...
Functional overreaching (FOR) occurs when athletes experience improved athletic capabilities in the days and weeks following short-term periods of increased training demand. However, prolonged high training demand with insufficient recovery may also lead to non-functional overreaching (NFOR) or the overtraining syndrome (OTS). The aim of this research was to explore strength coaches' perceptions and experiences of planned overreaching (POR); short-term periods of increased training demand designed to improve athletic performance. Fourteen high-performance strength coaches (weightlifting; n = 5, powerlifting; n = 4, sprinting; n = 2, throws; n = 2, jumps; n = 1) participated in semistructured interviews. Reflexive thematic analysis identified 3 themes: creating enough challenge, training prescription, and questioning the risk to reward. POR was implemented for a 7 to 14 day training cycle and facilitated through increased daily/weekly training volume and/or training intensity. Participants implemented POR in the weeks (~5–8 weeks) preceding competition to allow sufficient time for performance restoration and improvement to occur. Short-term decreased performance capacity, both during and in the days to weeks following training, was an anticipated by-product of POR, and at times used as a benchmark to confirm that training demand was sufficiently challenging. Some participants chose not to implement POR due to a lack of knowledge, confidence, and/or perceived increased risk of athlete training maladaptation. Additionally, this research highlights the potential dichotomy between POR protocols used by strength coaches to enhance athletic performance and those used for the purpose of inducing training maladaptation for diagnostic identification.
... Additionally, it was expected that protein supplementation could improve parameters related to the DOMS [53][54][55]. According to Ra et al. [41], DOMS in response to muscle stimuli is influenced by feeding or fasting before exercise performance. ...
Due to the utilization of milk proteins such as whey protein (WP) and casein as sports nutrition ergogenic aids, the present study investigated the effects of the association of WP and casein in a ratio of 80:20, a similar ratio of human breast milk, on blood branched-chain amino acid (BCAA) profiles, markers of protein metabolism and delayed onset muscle soreness (DOMS), after a single bout of resistance exercise. A double-blind, crossover and acute study was carried out with ten men (age 29 ± 8 years; BMI: 25.4 ± 2.9 kg/m2; 77 ± 12 kg; 1.74 ± 0.09 m); each one consumed the following supplements randomly, one per session: WP, CAS (casein), WP/CAS (80% WP/20% CAS), CAS/WP (80% CAS/20% WP) and PLA (placebo). They were also subjected to the following evaluations: the one repetition maximum (1RM) test; resistance training session; blood extraction during each session to determine the BCAA profile; two food records; 3-day evaluation of DOMS (24 h, 48 h and 72 h) and nitrogen balance in each treatment. The intervention resulted in similar nitrogen urinary, creatinine and urea plasma levels and showed a positive nitrogen balance in all the trials. Regarding the BCAAs, the peak occurred at 60 min post-ingestion and remained higher until 120 min for WP, WP/CAS and CAS/WP. The DOMS was significantly lower for WP, WP/CAS and CAS/WP compared to the CAS and PLA treatments. There were no advantages in the association of WP and CAS in the BCAAs profile when compared to WP itself, but it induced a lower DOMS compared to CAS and PLA (Clinical Trial registration number: clinicaltrials.gov, NCT04648384).
... It is well-accepted that protein consumption following an intense workout can enhance the recovery and remodeling processes within skeletal tissue (Jäger et al. 2017). Several studies have reported a decrease in the extent of muscle damage, attenuation in force decrements, and enhanced recovery resulting from protein ingestion following resistance exercise (Kraemer et al. 2006;Hoffman et al. 2007;Hulmi et al. 2009;Cooke et al. 2010;Hoffman 2016). When protein is consumed prior to, and immediately following a bout of resistance exercise an increase in messenger RNA (mRNA) expression is observed, preventing a post-exercise decrease in myogenin mRNA expression (Hulmi et al. 2009). ...
There have been a multitude of reviews written on exercise-induced muscle damage (EIMD) and recovery. EIMD is a complex area of study as there are a host of factors such as sex, age, nutrition, fitness level, genetics and familiarity with exercise task, which influence the magnitude of performance decrement and the time course of recovery following EIMD. In addition, many reviews on recovery from exercise have ranged from the impact of nutritional strategies and recovery modalities, to complex mechanistic examination of various immune and endocrine signaling molecules. No one review can adequately address this broad array of study. Thus, in this present review, we aim to examine EIMD emanating from both endurance exercise and resistance exercise training in recreational and competitive athletes and shed light on nutritional strategies that can enhance and accelerate recovery following EIMD. In addition, the evaluation of EIMD and recovery from exercise is often complicated and conclusions often depend of the specific mode of assessment. As such, the focus of this review is also directed at the available techniques used to assess EIMD.
... On the other hand, it appears that supplementation with branched-chain amino acids (BCAA) after high-intensity exercise may favor a hormonal environment that contributes to attenuate the loss of strength, reduce muscle damage, and generate an anabolic environment [127]. Indeed, several systematic reviews and meta-analysis have concluded that BCAA supplementation (>200 mg·kg −1 ·day −1 ) may optimize recovery and mitigate muscle soreness following muscle-damaging exercise [128][129][130][131]. Notwithstanding, in resistancetrained males, the attenuation of muscular performance decrements and the observed decrease in plasma CK levels after BCAA supplementation is likely negligible when consumed with a diet consisting of ~1.2 g·kg −1 ·day −1 of protein [132]. ...
Post-exercise recovery is a broad term that refers to the restoration of training capacity. After training or competition, there is fatigue accumulation and a reduction in sports performance. In the hours and days following training, the body recovers and performance is expected to return to normal or improve. ScienceDirect, PubMed/MEDLINE, and Google Scholar databases were reviewed to identify studies and position declarations examining the relationship between nutrition and sports recovery. As an evidence-based framework, a 4R’s approach to optimizing post-exercise recovery was identified: (i) Rehydration—a fundamental process that will depend on the athlete, environment and sports event; (ii) Refuel—the consumption of carbohydrates is not only important to replenish the glycogen reserves but also to contribute to the energy requirements for the immune system and tissue reparation. Several bioengineered carbohydrates were discussed but further research is needed; (iii) Repair—post-exercise ingestion of high-quality protein and creatine monohydrate benefit the tissue growth and repair; and (iv) Rest—pre-sleep nutrition has a restorative effect that facilitates the recovery of the musculoskeletal, endocrine, immune, and nervous systems. Nutritional consultancy based on the 4R’s is important for the wise stewardship of the hydration, feeding, and supplementation strategies to achieve a timely recovery.
... The use of EAA as the only or main source of nitrogen has been rarely tested [12], more frequent is the use of EAA based formulations as supplement to diets [20], [21], [22] and It is of notice that plasma urea never rises to pathological values in those studies, even if the amount of nitrogen supplied as EAA was extremely significant. ...
Low plasma albumin levels have been historically associated with insufficient nutritional nitrogen support. Recently, linked to the poor response of actual therapies and available supplements to manage this alteration, the role of this alteration has been attributed to the vast ensemble of modifications referred generally as consequent to inflammation. On the contrary, as recently it has been reported that life based on introduction of mainly essential amino acids is possible, and life span is improved when compared to standard diets, it is possible to hypothesize that by normal foods or by actually most widely diffused supplements insufficient amounts of essential amino acids to match with real needs of hypoalbuminemic patients are not provided. Peculiarly, some non essential amino acids provided in excess by diets may mislead clinicians by suggesting achievement of sufficient nitrogen intake if urea syntheses is used as reference of sufficient nutrition, while syntheses of liver proteins is not sufficiently implemented. Studies suitable to understand if some innovative therapy would be efficient in implementing albumin syntheses and thus prognosis in hypoalbuminemic patients are necessary.
... One of the benefits associated with protein consumption following an intense workout is in its ability to enhance the recovery and remodeling processes within skeletal tissue [22]. Several studies have reported a decrease in the extent of muscle damage, attenuation in force decrements, and an enhanced recovery from protein ingestion following resistance exercise [2,[23][24][25][26]. Hulmi and colleagues [2] have shown that when protein is consumed prior to, and immediately following a bout of resistance exercise an increase in messenger RNA (mRNA) expression is observed, preventing a post-exercise decrease in myogenin mRNA expression. ...
To optimize athletic performance and enhance recovery from high intensity training,the competitive athlete needs to ensure adequate energy and protein consumption.Differences in protein requirements for athletes, non-athletes and different types ofathletes (i.e., endurance vs. strength/power) are well acknowledged. This has resulted inmany athletes using protein supplements as a means of achieving their recommendedprotein intake and often to exceed the recommended amounts. In the past few years, anumber of studies have focused on whether the timing of protein ingestion as it relates toa workout enhances protein synthesis and muscle recovery. This chapter focuses onprotein requirements for different types of athletes and whether protein timing providesany advantage on affecting performance gains and recovery. Considering the high proteinintake for many athletes, a discussion will also be directed to the safety aspects of highprotein consumption
... 26 Furthermore, increasing dietary protein (3 g/kg/day) during a 2-week block of high-intensity training in cyclists restored the exercise-induced leucocyte trafficking impairment, with fewer symptoms of upper respiratory tract infections. 50 In accordance with the aforementioned studies in endurance training models of OR, additional protein in the form of amino acids served to attenuate decrements in performance and increases in muscle damage observed in high volume resistance training OR. 51 Periodised adjustments to the athlete's protein intake may serve to modify the impact of intensified periods of training on measures of fatigue and immunity, and enhance performance outcomes. Indeed, it should be emphasised that the periodisation of nutritional support, consisting of adjustments to energy and macronutrients (eg, carbohydrate and protein) and micronutrient intakes around training phases (eg, iron, magnesium, vitamin D), and most crucially intensified training blocks, are a critical element of the successful optimisation of performance, and prevention of UUPS. ...
The coach and interdisciplinary sports science and medicine team strive to continually progress the athlete's performance year on year. In structuring training programmes, coaches and scientists plan distinct periods of progressive overload coupled with recovery for anticipated performances to be delivered on fixed dates of competition in the calendar year. Peaking at major championships is a challenge, and training capacity highly individualised, with fine margins between the training dose necessary for adaptation and that which elicits maladaptation at the elite level. As such, optimising adaptation is key to effective preparation. Notably, however, many factors (eg, health, nutrition, sleep, training experience, psychosocial factors) play an essential part in moderating the processes of adaptation to exercise and environmental stressors, for example, heat, altitude; processes which can often fail or be limited. In the UK, the term unexplained underperformance syndrome (UUPS) has been adopted, in contrast to the more commonly referenced term overtraining syndrome, to describe a significant episode of underperformance with persistent fatigue, that is, maladaptation. This construct, UUPS, reflects the complexity of the syndrome, the multifactorial aetiology, and that ‘overtraining’ or an imbalance between training load and recovery may not be the primary cause for underperformance. UUPS draws on the distinction that a decline in performance represents the universal feature. In our review, we provide a practitioner-focused perspective, proposing that causative factors can be identified and UUPS explained, through an interdisciplinary approach (ie, medicine, nutrition, physiology, psychology) to sports science and medicine delivery, monitoring, and data interpretation and analysis.
... Strength and Conditioning Journal | www.nsca-scj.com Because of extensive existing research regarding the effectiveness of creatine, caffeine, BA, BCAA, and essential amino acids on strength and power ( Figure 1) (7,28,42,85), these ingredients are not discussed in this review. In addition, because of the plethora of supportive ingredients commonly listed on MIPS supplement facts labels, we discuss ingredients that compose .5% of commonly used MIPS ( Figure 2). ...
THIS REVIEW SUMMARIZES THE EMPIRICAL RESEARCH OF THE EFFECTIVENESS, SAFETY, AND DOSAGES OF THE LESSER-KNOWN, BUT COMMONLY ADDED, SUPPORTIVE INGREDIENTS IN MULTI-INGREDIENT PERFORMANCE SUPPLEMENTS (MIPS). PRIMARY INGREDIENTS THAT ARE WELL KNOWN AND PREVIOUSLY REVIEWED (I.E., CAFFEINE, CREATINE, BETA-ALANINE) ARE EXCLUDED FROM THIS REVIEW. THE IMPROVEMENTS REPORTED ARE COMMONLY MEDIATED BY SECONDARY MECHANISMS SUCH AS IMPROVED BLOOD FLOW, PROTEIN BALANCE, METABOLISM, AND ANTIOXIDANT STATUS. OVERWHELMING EVIDENCE EXISTS SUGGESTING THAT THE SUPPORTIVE INGREDIENTS IN MIPS ARE SAFE TO USE; HOWEVER, THE AMOUNT PRESENT IN MOST MIPS IS LIKELY TOO SMALL TO ELICIT STRENGTH, POWER, OR RECOVERY RESPONSES.
... The other 3 subjects started with the control condition, after which they switched to the peptide intake condition. 2 Norikazu Hirose, et al. the positive eŠect of nutritional supplementation on decreasing DOMS and muscle damage (Coombes and McNaughton, 2000; Kraemer et al., 2006; Sugita et al., 2003). For example, Nosaka et al. (2006) found that continuous intake of amino acids following endurance exercise decreased DOMS and muscle damage. ...
The aim of this study was to examine the in‰uence of milk peptide intake on the recovery from muscle damage following high-intensity eccentric exercise. To clarify this issue, we designed a cross over comparison study between peptide intake and control after eccentric calf raise exercise. Six healthy male volunteers (ranging from 19 to 22 years) performed high-intensity eccentric calf raise exercise. The CK, MRI T2 value of the calf were measured at pre-, post-, and on, day 1, 2, 3, 5 and 8 following the exercise to evaluate muscle damage as well as muscle soreness using a visual analog scale (VAS). Statistical diŠerences in all measurements between the peptide and control condition were analyzed using two-factorial ANOVA. The peak value of each measurement between two trials was analyzed using the T-test. A statistical signiˆcance of pº0.05
was adopted. The peak CK level (pº0.05), MRI T2 value (pº0.05), and VAS (pº0.01) in the peptide condition
were signiˆcantly lower than those in control. Although the mechanism of recovery from muscle damage is unclear, our ˆnding suggests that milk peptide intake may be eŠective for decreasing muscle damage after high-intensity eccentric exercise.
... One BCAA of particular interest is leucine, which has been shown to increase muscle protein synthesis (MPS) without the presence of the other essential amino acids
[18] Additionally, Karlsson et al.
[19] found that supplementation with BCAAs during resistance exercise results in greater phosphorylation of ribosomal S6 kinase, a rate limiting enzyme in the signaling network responsible for regulation of protein synthesis in skeletal muscles. Moreover, BCAAs seem to decrease soreness after eccentric exercise
[20] and, they prevent declines in both testosterone and power following an overreaching cycle
[21]. ...
Xpand(R) 2X is a proprietary blend comprised of branched chain amino acids, creatine monohydrate, beta-alanine (CarnoSyn(R)), quercetin, coenzymated B-vitamins, alanyl-glutamine (Sustamine(R)), and natural nitrate sources from pomegranate and beet root extracts purported to enhance the neuromuscular adaptations of resistance training. However to date, no long-term studies have been conducted with this supplement. The purpose of this study was to investigate the effects of a multi-ingredient performance supplement (MIPS) on skeletal muscle hypertrophy, lean body mass and lower body strength in resistance-trained males.
Twenty resistance-trained males (21.3 +/- 1.9 years) were randomly assigned to consume a MIPS or a placebo of equal weight and volume (food-grade orange flavors and sweeteners) in a double-blind manner, 30 minutes prior to exercise. All subjects participated in an 8-week, 3-day per week, periodized, resistance-training program that was split-focused on multi-joint movements such as leg press, bench press, and bent-over rows. Ultrasonography measured muscle thickness of the quadriceps, dual-energy X-ray absorptiometry (DEXA) determined lean body mass, and strength of the bench press and leg press were determined at weeks 0, 4, and 8 of the study. Data were analyzed with a 2 x 3 repeated measures ANOVA with LSD post hoc tests utilized to locate differences.
There was a significant group-by-time interaction in which the MIPS supplementation resulted in a significant (p < 0.01) increase in strength of the bench press (18.4% vs. 9.6%) compared with placebo after 4 and 8 weeks of training. There were no significant group by time interactions between MIPS supplementation nor the placebo in leg press strength (p = .08). MIPS supplementation also resulted in a significant increase in lean body mass (7.8% vs. 3.6%) and quadriceps muscle thickness (11.8% vs. 4.5%) compared with placebo (group*time, p <0.01).
These results suggest that this MIPS can positively augment adaptations in strength, and skeletal muscle hypertrophy in resistance-trained men.
... Nutrition does play a role in athlete performance, but dietary supplements are not generally needed by athletes and in many instances may contribute to negative outcomes experienced by athletes. Habitual intakes of multiple substances add to the complexity and physiological stresses of extreme training regimes and environments (Kraemer, Ratamess, Volek, Häkkinen, Rubin, French, Gómez, McGuigan, Scheett, Newton, Spiering, Izquierdo, & Dioguardi, 2006). The Food and Nutrition Board of the Institute of Medicine (IOM) recently established new Dietary Reference Intakes for water for healthy people (Food and Nutrition Board, 2004). ...
Training and competing in desert environments may exacerbate concerns related to disordered eating, supplement use, and hydration in some student athlete populations. A survey
... Sports nutrition scientists have attempted to increase training induced gains through a number of protocols, which generally attempt to augment and/or speed skeletal muscle regeneration. One such intervention has been to increase the provision of the branched chain amino acids (BCAAs), leucine, isoleucine, and valine, which make up more than one third of muscle protein [5]. The BCAAs are unique among the essential amino acids (EAAs) for their roles in protein metabolism [6], neural function [7-9], and blood glucose and insulin regulation [10]. ...
Background
Consumption of moderate amounts of animal-derived protein has been shown to differently influence skeletal muscle hypertrophy during resistance training when compared with nitrogenous and isoenergetic amounts of plant-based protein administered in small to moderate doses. Therefore, the purpose of the study was to determine if the post-exercise consumption of rice protein isolate could increase recovery and elicit adequate changes in body composition compared to equally dosed whey protein isolate if given in large, isocaloric doses.
Methods
24 college-aged, resistance trained males were recruited for this study. Subjects were randomly and equally divided into two groups, either consuming 48 g of rice or whey protein isolate (isocaloric and isonitrogenous) on training days. Subjects trained 3 days per week for 8 weeks as a part of a daily undulating periodized resistance-training program. The rice and whey protein supplements were consumed immediately following exercise. Ratings of perceived recovery, soreness, and readiness to train were recorded prior to and following the first training session. Ultrasonography determined muscle thickness, dual emission x-ray absorptiometry determined body composition, and bench press and leg press for upper and lower body strength were recorded during weeks 0, 4, and 8. An ANOVA model was used to measure group, time, and group by time interactions. If any main effects were observed, a Tukey post-hoc was employed to locate where differences occurred.
Results
No detectable differences were present in psychometric scores of perceived recovery, soreness, or readiness to train (p > 0.05). Significant time effects were observed in which lean body mass, muscle mass, strength and power all increased and fat mass decreased; however, no condition by time interactions were observed (p > 0.05).
Conclusion
Both whey and rice protein isolate administration post resistance exercise improved indices of body composition and exercise performance; however, there were no differences between the two groups.
... Supplementing the diet with the amino acid leucine in combination with resistance training may increase lean body mass (LBM), strength and decrease body fat [1-3]. Moreover, leucine appears to decrease skeletal muscle soreness following eccentric exercise [4], and prevent declines in both circulating testosterone and skeletal muscle power following an overreaching cycle [5]. Leucine has been thought to augment adaptations to strength training by acting as the primary signal to activate protein synthesis (e.g. ...
Position Statement: The International Society of Sports Nutrition (ISSN) bases the following position stand on a critical analysis of the literature on the use of beta-hydroxy-beta-methylbutyrate (HMB) as a nutritional supplement. The ISSN has concluded the following. 1. HMB can be used to enhance recovery by attenuating exercise induced skeletal muscle damage in trained and untrained populations. 2. If consuming HMB, an athlete will benefit from consuming the supplement in close proximity to their workout. 3. HMB appears to be most effective when consumed for 2 weeks prior to an exercise bout. 4. Thirty-eight mg.kg.BM-1 daily of HMB has been demonstrated to enhance skeletal muscle hypertrophy, strength, and power in untrained and trained populations when the appropriate exercise prescription is utilized. 5. Currently, two forms of HMB have been used: Calcium HMB (HMB-Ca) and a free acid form of HMB (HMB-FA). HMB-FA may increase plasma absorption and retention of HMB to a greater extent than HMB-CA. However, research with HMB-FA is in its infancy, and there is not enough research to support whether one form is superior. 6. HMB has been demonstrated to increase LBM and functionality in elderly, sedentary populations. 7. HMB ingestion in conjunction with a structured exercise program may result in greater declines in fat mass (FM). 8. HMB's mechanisms of action include an inhibition and increase of proteolysis and protein synthesis, respectively. 9. Chronic consumption of HMB is safe in both young and old populations.
Athletes should follow these rules in order to optimize their nutrition. Eat enough calories to offset energy expenditure (typically 50–80 kcal/kg/day). Consume the proper amount of carbohydrate (e.g., 5–8 g/kg/day during normal training and 8–10 g/kg/day during heavy training), protein (1.2–2.0 g/kg/day), and fat (0.5–1.5 g/kg/day). Ingest meals and snacks at appropriate time intervals prior to, during, and/or following exercise in order to provide energy as well as to promote recovery following exercise; include more liquid and quickly digestible type forms of nutrition within an hour of exercise; Ensure athletes are properly hydrated prior to exercise and competition. Incorporate rest and nutritional strategies to optimize recovery. Only consider using nutritional supplements that have been found to be an effective and safe means for improving performance capacity and/or enhancing recovery.KeywordsAthletic dietSports nutritionErgogenic aidsNutrient timing
Testosterone plays an important role in maintaining both physical and mental function. Age-related testosterone depletion contributes to the development of angina, arteriosclerosis, obesity, metabolic syndrome, dementia, frailty, and a range of other conditions. A condition involving age-related testosterone depletion and the associated clinical symptoms is defined as late-onset hypogonadism (LOH). LOH is treated by testosterone replacement therapy. Indications for testosterone replacement therapy are determined by evaluating symptoms and signs.
Over the past decades, the rapid population growth coupled with growing awareness towards nutrition has driven an increasing demand for organic acids (e.g., carboxylates) and proteins in pharmaceutical and food products. However, close to 50-70% of the overall production cost of organic acids and proteins in bio and food manufacturing processes comes from separation processes. Recently, electrochemically-mediated separations have gained significant attention as an alternative solution, bringing potential benefits in process intensification and low chemical consumption. Here, we review progress in electrochemical processes for the recovery of organic acids and proteins, in bio and food manufacturing contexts such as fermentation, and the dairy and pharmaceutical industries. We highlight aspects of the electrochemical engineering of these systems, selection of electrode materials, and discuss the underlying separation mechanisms. We emphasize the need for understanding molecular level selectivity coupled with engineering design, for broadening the applicability of electrochemical platforms for selective bioproduct purification. On the long term, electrochemical separations can provide a sustainable and competitive platform for the recovery of numerous value-added molecules in bio and food manufacturing processes.
Aquaculture is increasingly important for providing humans with high-quality animal protein to improve growth, development and health. Farm-raised fish and shellfish now exceed captured fisheries for foods. More than 70% of the production cost is dependent on the supply of compound feeds. A public debate or concern over aquaculture is its environmental sustainability as many fish species have high requirements for dietary protein and fishmeal. Protein or amino acids (AAs), which are the major component of tissue growth, are generally the most expensive nutrients in animal production and, therefore, are crucial for aquatic feed development. There is compelling evidence that an adequate supply of both traditionally classified nutritionally essential amino acids (EAAs) and non-essential amino acids (NEAAs) in diets improve the growth, development and production performance of aquatic animals (e.g., larval metamorphosis). The processes for the utilization of dietary AAs or protein utilization by animals include digestion, absorption and metabolism. The digestibility and bioavailability of AAs should be carefully evaluated because feed production processes and AA degradation in the gut affect the amounts of dietary AAs that enter the blood circulation. Absorbed AAs are utilized for the syntheses of protein, peptides, AAs, and other metabolites (including nucleotides); biological oxidation and ATP production; gluconeogenesis and lipogenesis; and the regulation of acid-base balance, anti-oxidative reactions, and immune responses. Fish producers usually focus on the content or digestibility of dietary crude protein without considering the supply of AAs in the diet. In experiments involving dietary supplementation with AAs, inappropriate AAs (e.g., glycine and glutamate) are often used as the isonitrogenous control. At present, limited knowledge is available about either the cell- and tissue-specific metabolism of AAs or the effects of feed processing methods on the digestion and utilization of AAs in different fish species. These issues should be addressed to develop environment-friendly aquafeeds and reduce feed costs to sustain the global aquaculture.
The purpose of the present study was to compare the effects of short‐term high‐frequency failure versus non‐failure blood flow‐restricted resistance exercise (BFRRE) on changes in satellite cells (SC), myonuclei, muscle size and strength. Seventeen untrained men performed 4 sets of BFRRE to failure (Failure) with one leg and not to failure (Non‐failure; 30‐15‐15‐15 repetitions) with the other leg using knee‐extensions at 20% of 1RM. Fourteen sessions were distributed over two five‐day blocks, separated by a ten‐day rest period. Muscle samples obtained before, at mid‐training, and 10 days post‐intervention (Post10) were analyzed for muscle fiber area (MFA), myonuclei, and SC. Muscle size and echo intensity of m.rectus femoris (RF) and m.vastus lateralis (VL) were measured by ultrasonography, and knee extension strength with 1RM and maximal isometric contraction (MVC) up until Post24. Both protocols increased myonuclear numbers in type‐1 (12‐17%) and type‐2 fibers (20‐23%), and SC in type‐1 (92‐134%) and type‐2 fibers (23‐48%) at Post10 (p<0.05). RF and VL size increased by 5‐10% in both legs at Post10 to Post24, whereas the MFA of type‐1 fibers in Failure was decreased at Post10 (‐10±16%; p=0.02). Echo intensity increased by ~20% in both legs during Block1 (p<0.001) and was ~8‐11% below baseline at Post24 (p=0.001‐0.002). MVC and 1RM decreased by 5‐10% after Block1, but increased in both legs by 6‐11% at Post24 (p<0.05). In conclusion, short‐term high‐frequency failure and non‐failure BFRRE both induced increases in satellite cells, in myonuclei content, muscle size and strength, concomitant with decreased echo intensity. Intriguingly, the responses were delayed and peaked 10‐24 days after the training intervention. Our findings may shed light on the mechanisms involved in resistance exercise‐induced overreaching and supercompensation.
Background
The balance between training stress and recovery is important for inducing adaptations to improve athletic performance. However, continuously high training loads with insufficient recovery may cause fatigue to accumulate and result in overtraining. A comprehensive systematic review is required to collate overtraining literature and improve the current understanding of the mechanisms underlying functional overreaching (FOR), non-functional overreaching (NFOR) and the overtraining syndrome (OTS) in resistance training.
Objective
The objective of this systematic review was to establish markers of overtraining and elucidate the mechanisms underlying maladaptive resistance training conditions. Furthermore, this review aims to critically evaluate the methodological approaches of the overtraining literature.
Methods
A systematic literature search was performed on PubMed, Web of Science and SPORTDiscus to identify studies up to June 2019. Electronic databases were searched using terms related to resistance training and overtraining. Records were included if they attempted to induce a state of overreaching or overtraining through resistance exercise in healthy participants.
Results
A total of 22 studies were selected for review. Among these studies, eight resulted in decrements in performance and measured changes in performance during a follow-up period. There were four studies that reported decrease in performance yet failed to implement follow-up measures. A total of 10 studies reported no decline in performance. Overall, a lack of standardisation in methodology (follow-up performance testing) and diagnostic criteria prevents consistent determination of FOR, NFOR and OTS in resistance training.
Conclusions
Few studies have appropriately established FOR, NFOR or OTS in resistance training. Overtraining may be related to frequent high-intensity and monotonous resistance training. However, no marker other than a sustained decrease in performance has been established as a reliable indicator of overtraining in resistance exercise.
Registration
This systematic review was registered on the Open Science Framework (https://osf.io/) ( https://doi.org/10.17605/osf.io/5bmsp).
Previous research has documented positive effects of periodised muscular endurance resistance training in untrained men and women. Therefore, the overarching objective of this thesis was to compare the efficacy of two resistance training progression models [linear periodisation (LP) vs. undulating periodisation (UP)], and to elucidate the best method to vary the exercise stimulus to develop muscular endurance in trained youth athletes. With respect to the overarching objective of this thesis, a series of studies were conducted.
The first aim was to identify the reliability and sensitivity of neuromuscular function variables in trained youth athletes. Second, to investigate acute neuromuscular function, endocrine and perceptual wellbeing responses following two different muscular endurance resistance training sessions [3 sets of 25 repetition maximum (RM) and 3 sets of 15RM]. Lastly, to investigate the effects of two distinct resistance training models (LP vs. UP) on selected performance, physiological and psychological variables in trained youth team sports athletes. Also, the different physiological, neuromuscular, perceptual wellbeing responses within this process were described and implications for athlete monitoring discussed.
It was found that the reliability and sensitivity of neuromuscular function variables was unique to the population in question. Specifically, only countermovement jump mean force [CMJMF; smallest worthwhile change (SWC) = 2.7%, coefficient of variation (CV) = 1.0%)], countermovement jump mean power (CMJMP; SWC = 3.2%, CV = 2.7%), countermovement jump peak power (CMJPP; SWC = 3.4%, CV = 3.0%) and plyometric push up mean force (PPMF; SWC = 2.9%, CV = 2.2%) displayed acceptable reliability (CV < 5%) and sensitivity in field hockey youth athletes.
Next, neuromuscular function, endocrine and perceptual wellbeing measures, obtained from trained youth participants, maintained similar acute biological responses irrespective of muscular endurance resistance training protocols. Force and power measures (CMJMF, CMJMP, CMJPP and PPMF) improved (p ≤ 0.05) 48 hours following both muscular endurance resistance training programmes. At 72 hours, testosterone: cortisol ratio (T:C ratio) showed a moderate increase [effect size (ES) = 0.72] following the 15RM protocol whereas a small decrease (ES = 0.41) was observed after the 25RM session. Overall perceptual wellbeing, fatigue and soreness scores reflected changes in neuromuscular function, while stress, sleep and mood did not show any differences.
Finally, muscular endurance tests demonstrated that UP (back squat ES = 1.62; bench press ES = 1.77) was more efficacious than LP (back squat ES = 0.69; bench press ES = 1.72) following 12 weeks of resistance training. Resting salivary testosterone concentration increased in the UP (31.47%) compared to LP (- 8.73%) group, whereas salivary cortisol concentration and T:C ratio remained unchanged. Session rating of perceived exertion (session RPE), mood and stress scores were frequently higher during training phase II (four weeks) and III (four weeks) compared to phase I (four weeks). No changes were detected in neuromuscular function.
Overall, this thesis offered several practical applications from the findings. First, the reliability and sensitivity of neuromuscular function variables were population specific. As such, practitioners are encouraged to establish the reliability and determine the neuromuscular function variable/s within the group to be trained. Second, as fatigue is multifaceted, practitioners should not rely on a single monitoring approach and incorporate both physiological and psychological aspects to monitor resistance training. Lastly, practitioners working with team sports athletes and intending to develop muscular endurance, can employ UP, performed in conjunction with sport specific training. Most importantly, it is highly advantageous to integrate a suitable monitoring measure, to direct appropriate sequencing of training loads, to result in optimal athletic performance.
Water temperature directly affects the body temperature in fish, so increasing water temperatures in oceans and rivers will lead to increases in fish body temperatures. Whilst a range of responses of fish to increases in water temperature have been measured, amino acid metabolism in a fish under high water temperature (HT) conditions has not been investigated. The aim of this study was to determine the effects of an acute increase in water temperature on oxygen consumption, plasma cortisol concentrations, and free amino acid concentrations in plasma and several tissues in goldfish (Carassius auratus). Oxygen consumption and plasma cortisol concentrations were increased in goldfish exposed to HT (30 ± 1 °C) for 200 min compared with goldfish at a control water temperature (CT 17 ± 1 °C). Oxygen consumption and plasma cortisol concentrations in both groups of fish combined were positively correlated. When goldfish were exposed to HT for 300 min oxygen consumption and plasma concentrations of 15 free amino acids were increased compared with goldish at CT. Concentrations of several free amino acids were increased to varying extents in the brain, liver, and muscle tissues. In conclusion, an acute increase in water temperature affected amino acid metabolism differently in the brain, liver, and muscle tissues. Goldfish will be a useful species for further studies of the possible roles of various amino acids in the brain, muscle, and liver during acute increases in water temperature in fish.
Background: Unhealthy western dietary patterns lead to over-consumption of fat and advanced glycation end-products (AGEs), and these account for the developments of obesity, diabetes, and related metabolic disorders. Certain amino acids (AAs) have been recently demonstrated to improve glycemia and reduce adiposity. Therefore, our primary aims were to examine whether feeding an isoleucine-enriched AA mixture (4.5% AAs; Ile: 3.0%, Leu: 1.0%, Val: 0.2%, Arg: 0.3% in the drinking water) would affect adiposity development and prevent the impairments of glycemic control in rats fed with the fat/AGE-containing diet (FAD).
Methods: Twenty-four male Sprague-Dawley rats were assigned into 1) control diet (CD, N = 8), 2) FAD diet (FAD, N = 8), and 3) FAD diet plus AA (FAD/AA, N = 8). After 9-weeks intervention, the glycemic control capacity (glucose level, ITT, and HbA1c levels), body composition, and spontaneous locomotor activity (SLA) were evaluated, and the fasting blood samples were collected for analyzing metabolic related hormones (insulin, leptin, adiponectin, and corticosterone). The adipose tissues were also surgically collected and weighed.
Results: FAD rats showed significant increases in weight gain, body fat %, blood glucose, HbA1c, leptin, and area under the curve of glucose during insulin tolerance test (ITT-glucose-AUC) in compared with the CD rats. However, the fasting levels of blood glucose, HbA1c, leptin, and ITT-glucose-AUC did not differ between CD and FAD/AA rats. FAD/AA rats also showed a greater increase in serum testosterone.
Conclusion: The amino acid mixture consisting of Ile, Leu, Val, and Arg showed clear protective benefits on preventing the FAD-induced obesity and impaired glycemic control.
The effects of a recovery drink on overreaching induced by high frequency, high power resistance exercise was assessed. Resistance trained men were assigned to a supplemented (SUP, n = 8), placebo (PL, n = 3) or control (CON, n = 6) groups. All groups completed two weeks of familiarization training using the barbell squat. In week three, SUP and PL performed ten sets of five repetitions of speed squats twice daily, for a total of 15 training sessions. CON maintained their prior training schedule. Data were collected before week three (T1), after week three (T2) and after a week of recovery by training cessation (T3). During week three, SUP consumed an amino acid, carbohydrate and creatine monohydrate containing recovery drink immediately after each training bout. PL was provided a drink of similar appearance and taste but containing minimal nutritional value. At T2, both SUP and PL decreased mean squat velocity and power at 70% 1RM. Additionally, SUP and PL decreased muscle β2-adrenergic receptor (β2-AR) expression by 61 and 83%, respectively. Increases in the ratio of nocturnal urinary epinephrine/β2-AR ratio (EPI: β2AR) for SUP and PL suggested impaired sympathetic nervous system sensitivity. SUP demonstrated a smaller decrease in β2-AR expression and a lower EPI: β2AR, suggesting the recovery drink attenuated the detrimental effects of overreaching on the sympathetic activity. In conclusion, high power resistance exercise overreaching can induce performance decrements and impair sympathetic activity, but these effects may be attenuated by supplementation.
Cancer cells require both energy and material to survive and duplicate in a competitive environment. Nutrients, such as amino acids (AAs), are not only a caloric source, as they can modulate cell metabolism and modify hormones homeostasis. Our hypothesis is that the environmental messages provided by AAs rule the dynamics of cancer cells life or death, and the alteration of the balance between essential (EAAs) and non-essential amino acids (NEAAs) (lower and higher than 50%, respectively) present in nutrients may represent a key instrument to alter environment-dependent messages thus mastering cancer cells destiny. In this study, two amino acid mixtures, one exclusively consisting of EAAs and the other consisting of 85% essential and 15% non-essential amino acids, were tested to explore their effects on the viability of both normal and cancer cell lines and to clarify the molecular mechanisms involved. Both mixtures exerted a cell-dependent anti-proliferative, cytotoxic effect involving the inhibition of proteasome activity and the consequent activation of autophagy and apoptosis. These results, besides further validating the notion of the peculiar interdependence and extensive crosstalk between the ubiquitin-proteasome system and autophagy, indicate that variation in the ratio of EAAs and NEAAs can deeply influence cancer cell survival. Consequently, customization of dietary ratios among EAAs and NEAAs by specific amino acid mixtures may therefore represent a promising anticancer strategy able to selectively induce death of cancer cells through the induction of apoptosis via both ubiquitin-proteasome system inhibition and autophagy activation. This article is protected by copyright. All rights reserved.
We examined if two different dietary interventions affected markers of soreness and inflammation over a 5-day high-volume resistance training protocol in females that resistance-trained 8 weeks prior. Twenty-eight females (age: 20 ± 1 yr; body mass: 63.5 ± 1.6 kg, height: 1.67 ± 0.01 m) completed 4 weeks of pre-training (weeks 1-4) followed by a subsequent 4-week training period along with a dietary intervention (weeks 5-8). Dietary interventions from weeks 5-8 included: a) no intervention (CTL, n = 10) b) a higher-protein diet supplemented with hydrolyzed whey protein (50 g/d) and omega-3 fatty acids (900 mg/d) (DI, n = 8), and c) the DI condition as well as creatine monohydrate (5 g/d) (DI+C, n = 10). During week 9, participants resistance-trained for five consecutive days whereby 8 sets of 10 target repetitions at 70% one repetition maximum (1RM) were performed each day for bench press, back squat, deadlift, and hip-thrusters with the intent of eliciting muscle soreness and inflammation. Prior to and 24 h following each of the 5 bouts muscle soreness (DOMS) was assessed via questionnaire, and fasting blood was obtained and analyzed for serum cortisol, interleukin-6 (IL-6) and C-reactive protein (CRP). No group*time (G*T) or time effects were observed for training volume over the 5-d overreaching protocol. Furthermore, no group*time (G*T) or time effects were observed for serum cortisol, IL-6 or CRP, and DOMS actually decreased in all groups 24 h following the fifth day training bout. This study demonstrates that, regardless of protein, omega-3 fatty acid and/or creatine supplementation, 5 days of consecutive resistance training does not alter perceived muscle soreness, training volume, and/or markers of inflammation in novice resistance-trained females.
This study aimed to determine the effects of a short-term, strength training intervention, typically undertaken by club-standard rowers, on 2,000 m rowing performance and strength and power development. Twenty-eight male rowers were randomly assigned to intervention or control groups. All participants performed baseline testing involving assessments of muscle soreness, creatine kinase activity (CK), maximal voluntary contraction (leg-extensors) (MVC), static-squat jumps (SSJ), counter-movement jumps (CMJ), maximal rowing power strokes (PS) and a 2,000 m rowing ergometer time-trial (2,000 m) with accompanying respiratory-exchange and electromyography (EMG) analysis. Intervention group participants subsequently performed three identical strength training (ST) sessions, in the space of five days, repeating all assessments 24 h following the final ST. The control group completed the same testing procedure but with no ST. Following ST, the intervention group experienced significant elevations in soreness and CK activity, and decrements in MVC, SSJ, CMJ and PS (
Guanidinoacetic acid (GAA) is a natural precursor of creatine and underinvestigation as a novel dietary supplement. However, its use in human nutrition ishampered by limited knowledge on its physiological effectiveness and safety aftersupplementation. The main aims of the present study were: (a) to identify if oral GAAaffects human performance and body composition; (b) to determine the most effectivedose regimen of GAA; and (c) to analyze the incidence and severity of adverse effects ofGAA supplementation. Fifty two (n = 52) male and female college athletes who wereexperienced in exercise training (> 2 years), and who were between 20 and 25 years ofage were included in the study. Participants were randomized in a double-blind design toreceive three different dosages of GAA (1.2 g/day, 2.4 g/day, and 4.8 g/day) or placebo(inulin) by oral administration for 6 weeks. Two-way mixed model ANOVA revealedsignificant increase in lean body mass (P = 0.006), handgrip strength (P = 0.03), andbench press performance (P = 0.014) in participants supplemented with GAA.Supplementation with GAA for 6 weeks had no major effect on indices of anaerobicpower and capacity. Low-dose GAA (1.2 g/day) can be considered as the minimumeffective dose for improving performance characteristics, while the effects are mostconsistently seen in participants receiving 2.4 g/day of GAA. Except for the dose of 4.8g/day of GAA, reported side effects of GAA administration are rather mild (e.g., weightgain, gastrointestinal distress). The findings of this study demonstrate that oral GAA is aneffective performance-enhancing agent with dose-dependent effects and mild side effectsexperienced when ingested over 6 weeks
Resistance exercise elicits an array of hormonal responses critical to acute muscular force and power production as well as subsequent tissue growth and remodeling. In general, the acute response is dependent upon the stimulus and may be the most critical element to tissue remodeling. Thus, modifications of training intensity, volume (or total work), muscle mass involvement, rest intervals, and frequency can impact the acute hormonal response. Long-term adaptations in neuroendocrine function seem minimal but may be related to the current intensity/volume of the training stimulus. The significance of these hormonal responses is not entirely known. For the sports nutritionist, the effect of various nutritional/supplemental strategies can indeed have an effect on the hormonal milieu. For instance, the timing of supplementation/feeding pre-and postexercise may affect the endocrine response to resistance exercise. Also, the consumption of various macronutrients can impact the basal concentration of various hormones.
Acne vulgaris (AV) is a common disease affecting all ages and ethnic groups. Androgens, skin and serum lipids, inflammatory signaling and regulatory neuropeptides seem to be involved in this multi-factorial process.
The aim of this work was to determine hormonal levels and lipid profile in non-obese, non-hirsute females with AV.
A total of 60 non-obese, non-hirsute female cases with different grades of AV and 60 age- and gender-matched healthy volunteers were included. Measurement of serum total and free testosterone, sex hormone binding globulin (SHBG), estradiol and progesterone and blood lipids was done during the luteal phase of the menstrual cycle.
Total testosterone, free testosterone (FT) and progesterone levels were significantly higher (P < 0.001 for all) while estradiol levels (P < 0.001) and SHBG (P < 0.01) were significantly lower in cases than controls. Total cholesterol and low density lipoprotein cholesterol (LDL-C) levels were significantly higher (P < 0.001 for both) while high density lipoprotein cholesterol (HDL-C) and apolipoprotein A-1 (ApoA-1) levels were significantly lower (P < 0.001 for both) in cases than controls. Higher values of FT (P = 0.03) and SHBG (P = 0.02) and lower values of estradiol (P = 0.04) levels were significantly in favor of severe acne. Higher values of cholesterol (P < 0.001) and LDL-C (P = 0.03) and lower values of HDL-C (P = 0.01) and ApoA-1 (P = 0.02) levels were significantly associated with severe acne.
Changes in hormone levels and lipid profile in non-obese and non-hirsute females with AV should be considered in disease pathogenesis and in treatment prescription of these patients.
The Effects of Whey Protein Supplementation on Performance and Hormonal Adaptations Following Resistance Training in Novice Men
Background: The purpose of this study was to determine the effects of whey protein supplementation on performance and hormonal changes during an 8-week resistance training program in novice weight trained men.
Material/Methods: Forty recreational weight trained men were randomly divided into a whey protein supplementation (WP) group (n=20), and a placebo (PL) group (n=20). Each group was given either whey protein or a placebo in a doubleblind manner to be taken orally for eight weeks (1.8g/kg/day). WP and PL groups performed the same weight training program 3 days, each week for 8 weeks. The training consisted of 3 sets of 8 repetitions, and the initial weight was 80% of the pre-1RM. Subjects were tested for performance and blood hormone concentrations before and after the 8-week period.
Results: The WP group achieved greater increases in body weight, explosive muscular power, muscle strength and blood testosterone when compared to the PL group; however, cortisol concentrations were significantly more reduced in WP group when compared to the PL group.
Conclusions: It can, therefore, be concluded that within 8 weeks whey protein supplementation was found to increase explosive muscular power, body weight and muscle strength.
The Effects of Whey Protein Supplementation on Performance and Hormonal Adaptations Following Resistance Training in Novice Men
The aim of this review is to highlight two emerging concepts for the elite athlete using the resistance-training model: (i) the short-term effects of testosterone (T) and cortisol (C) on the neuromuscular system; and (ii) the dose-response training role of these endogenous hormones. Exogenous evidence confirms that T and C can regulate long-term changes in muscle growth and performance, especially with resistance training. This evidence also confirms that changes in T or C concentrations can moderate or support neuromuscular performance through various short-term mechanisms (e.g. second messengers, lipid/protein pathways, neuronal activity, behaviour, cognition, motor-system function, muscle properties and energy metabolism). The possibility of dual T and C effects on the neuromuscular system offers a new paradigm for understanding resistance-training performance and adaptations.
Endogenous evidence supports the short-term T and C effects on human performance. Several factors (e.g. workout design, nutrition, genetics, training status and type) can acutely modify T and/or C concentrations and thereby potentially influence resistance-training performance and the adaptive outcomes. This novel short-term pathway appears to be more prominent in athletes (vs non-athletes), possibly due to the training of the neuromuscular and endocrine systems. However, the exact contribution of these endogenous hormones to the training process is still unclear. Research also confirms a dose-response training role for basal changes in endogenous T and C, again, especially for elite athletes. Although full proof within the physiological range is lacking, this athlete model reconciles a proposed permissive role for endogenous hormones in untrained individuals. It is also clear that the steroid receptors (cell bound) mediate target tissue effects by adapting to exercise and training, but the response patterns of the membrane-bound receptors remain highly speculative.
This information provides a new perspective for examining, interpreting and utilizing T and C within the elite sporting environment. For example, individual hormonal data may be used to better prescribe resistance exercise and training programmes or to assess the trainability of elite athletes. Possible strategies for acutely modifying the hormonal milieu and, thereafter, the performance/training outcomes were also identified (see above). The limitations and challenges associated with the analysis and interpretation of hormonal research in sport (e.g. procedural issues, analytical methods, research design) were another discussion point. Finally, this review highlights the need for more experimental research on humans, in particular athletes, to specifically address the concept of dual steroid effects on the neuromuscular system.
The purpose of this study was to examine the effect of glutamine supplementation on indices of recovery following eccentric exercise. In a randomized single-blind placebo-controlled design, 15 physically active males (mean age, 21 ± 1.5 years; mean height, 1.81 ± 0.07 m; mean body mass, 78.4 ± 9.2 kg) were assigned to a control or glutamine intervention group. Each participant performed 100 drop jumps from 0.6m followed by ingestion of 0.3 g · kg−1 body mass of maltodextrin mixed with 750 mL of distilled water and lemon flavoring (Control) or with an additional 0.3 g · kg−1 L-glutamine (Glutamine) at 0, 24, 48, and 72 hours post-exercise. Knee-extensor concentric peak torque at angular velocities of 0.52 and 3.14 rad · s−1, perceived muscle soreness, and plasma creatine kinase activity were measured at 0, 1, 24, 48, 72, and 96 hours post-exercise. L-glutamine supplementation resulted in a greater preservation of peak torque over the 96-hour measurement period at both 0.52 rad · s−1 (Control, 75 ± 16%; Glutamine, 85 ± 15% of pre-exercise values, p = 0.03) and 3.14 rad · s−1 (Control, 79 ± 16%; Glutamine, 90 ± 12%, p = 0.01). Muscle soreness was significantly lower over 96 hours with L-glutamine supplementation (Control, 4.6 ± 2.5 units; Glutamine, 3.6 ± 2.5 units, p = 0.03). L-glutamine supplementation did not affect the magnitude or temporal nature of the creatine kinase response. As a therapeutic intervention, glutamine supplementation was effective in attenuating strength loss and muscle soreness following eccentric exercise-induced muscle damage.
Protein supplement use is common among athletes, active adults, and military personnel. This review provides a summary of the evidence base that either supports or refutes the ergogenic effects associated with different mechanisms that have been proposed to support protein supplementation. It was clear that if carbohydrate delivery was optimal either during or after an acute bout of exercise that additional protein will not increase exercise capacity. Evidence was also weak to substantiate use of protein supplements to slow the increase in brain serotonin and onset of central fatigue. It was also evident that additional research is warranted to test whether the benefits of protein supplements for enhancing recovery of fluid balance after exercise will affect subsequent work in the heat. In contrast, with repeated exercise, use of protein supplementation was associated with reductions in muscle soreness and often a faster recovery of muscle function due to reductions in protein degradation. There was also good supportive evidence for long-term benefits of protein supplementation for gains in muscle mass and strength through accelerated rates of protein synthesis, as long as the training stimulus was of sufficient intensity, frequency, and duration. However, studies have not examined the impact of protein supplements under the combined stress of a military environment that includes repeated bouts of exercise with little opportunity for feeding and recovery, lack of sleep, and exposure to extreme environments. Both additional laboratory and field research is warranted to help provide evidence-based guidance for the choice of protein supplements to enhance soldier performance.
GROUPS OF AMINO ACIDS, AS WELL AS INDIVIDUAL AMINO ACIDS, HAVE BEEN STUDIED FOR THEIR ROLES IN PROTEIN BALANCE, HORMONE SECRETION, IMMUNE FUNCTION, OR CAPACITY TO BE CONVERTED TO VARIOUS ANABOLIC OR ANTICATABOLIC METABOLITES. SPECIFIC AMINO ACIDS WITH EXTENSIVE ANALYSIS INCLUDE THE ESSENTIAL AMINO ACIDS, BRANCHED CHAIN AMINO ACIDS, ARGININE, TAURINE, GLUTAMINE, β-ALANINE, AND THE LEUCINE METABOLITE, β-HYDROXY-β-METHYLBUTYRATE. THE PURPOSE OF THIS ARTICLE IS TO ANALYZE THE POSSIBLE ROLES AND PRACTICAL APPLICATIONS OF THESE AMINO ACIDS IN THE REGULATION OF BODY COMPOSITION AND PERFORMANCE IN ANAEROBIC AND AEROBIC SPORTS.
Following unaccustomed exercise consisting of lengthening (eccentric) contractions, delayed onset muscle soreness (DOMS) develops together with muscle weakness, and these symptoms persist for several days. DOMS and the impairment of muscle function due to muscle damage affect training and athletic performance; thus effective measures to prevent or reduce muscle damage, or enhance recovery from damage, are important. Since it is known that amino acid supplementation stimulates the transport of amino acids into the skeletal muscles, and administration of exagenous amino acids after exercise increases protein synthesis while reducing protein breakdown, it is plausible that amino acid supplementation is effective for reducing muscle damage and/or enhancing recovery from muscle damage. Several studies have investigated the effects of amino acid supplementation on DOMS and other markers of muscle damage, and some of them found positive effects while others did not. It should be noted that few studies found a positive effect of amino acid supplementation on recovery of muscle function, and no previous studies have investigated whether amino acid supplement facilitates regeneration of damaged contractile and/or non-contractile elements. It cannot be concluded from currently available information that amino acid supplementation is effective for recovery from muscle damage. However, it appears that the effects of amino acid supplementation on muscle damage, if any, are affected by the timing and amount of supplementation, the magnitude and cause of muscle damage, composition of amino acids in the supplement, and other food intake in addition to the supplement. These should be investigated further before concluding whether amino acid supplementation contributes to attenuation of muscle damage and enhances recovery of muscle function after damaging exercise.
Objective: The current literature offers ample evidence to support the use of amino acid therapy to prevent muscle soreness following overuse and to help maintain and restore muscle tissue following prolonged periods of inactivity. The purpose of this case report is to demonstrate that a carbohydrate-amino acid supplement can safely be used during physical therapy to prevent muscle soreness. Methods: A 74-year old female underwent elective hip replacement surgery followed by a week of rehabilitative physical therapy. The patient elected to use a carbohydrate- amino acid supplement as a means to prevent muscle soreness following physical therapy and consented to observation. Results: During the course of physical therapy the patient reported no muscle soreness on the days following therapy while using the carbohydrate-amino acid supplement. The one occasion where the supplement was not used following physical therapy, noticeable discomfort due to muscle soreness was reported. Conclusions: This case report supports the use of carbohydrate-amino acid supplementation to prevent muscle soreness while restoring lean muscle and strength following physical therapy, even though definite conclusions cannot be drawn from a single case report design. Current literature in conjunction with this case report supports the need for properly designed studies to further investigate the therapeutic benefits of a carbohydrate-amino acid supplement as an adjunct to physical therapy and rehabilitation.
This study was designed to determine endocrine responses during 2 days of strenuous resistance training. Ten healthy men performed resistance training twice a day for two successive days to induce acute fatigue (excessive physical stress). The resistance training consisted of four exercises for the lower body in the morning and seven exercises for the upper body in the afternoon. Maximal isometric and isokinetic strengths were measured from day 1 (before the training period) to day 3 (after the training period). Fasting blood samples were taken on days 1-3. Maximal isometric and isokinetic strengths significantly decreased with two successive days of training (P<0·05), with significant increases in serum creatine phosphokinase and myoglobin concentrations (P<0·05). Significant reductions in the fasting concentrations of serum insulin-like growth factor-1, free testosterone, insulin and high-molecular-weight adiponectin were observed on day 3 (P<0·05), whereas there were no changes in the serum cortisol concentration or the free testosterone/cortisol ratio. Plasma active ghrelin and serum leptin concentrations decreased by -20·7 ± 2·8% and -29·6 ± 4·1%, respectively (P<0·05). Two days strenuous resistance training significantly affects the profiles of anabolic hormone and endocrine regulators of appetite and energy balance, such as ghrelin and leptin. The present findings suggest that decreased ghrelin and leptin concentrations might reflect excessive physical stress and may be early signs of accumulated fatigue.
Resistance training increases muscle strength. Muscle strength gains are influenced by program design. This review attempted to identify design choices that would be best practices. A best practice is a design option that produces significantly better results than any other option. To ensure sensitive assessments of program design effects, statistical procedures adjusted for differences in program length, and allowed for the repeated measures structure of the study designs. Untrained individuals benefitted much more from training than trained individuals. Gender had little effect. Age effects differed for men and women. Given the impact of participant characteristics on the training response, the effects of different program design facets were examined separately for programs with untrained and trained participants. Periodization, number of sessions per week, number of sets per session, and intensity (number of repetitions per set) were significant moderators for untrained participants; sets per session and intensity were significant moderators for trained participants. However, comparisons generally showed that no single design option was significantly better than all others. The available evidence may rule out some design choices (e.g., a single set per session), but it is too limited to identify best practices.
SOUZA JUNIOR, T. P.; GUALANO, B.; PRESTES, J.; RIBEIRO, S. M. L.; AOKI, M. S. Biomotricity Round table -Dietary supplements and muscular hypertrophy. Brazilian Journal Biomotricity, v. 4, n. 4, p. 227-245, 2010. The aims of this Round Table were: a) present the opinions of researchers regarding the efficiency nutritional supplements developed for strength gains and muscle growth, b) discuss the perspectives for future research involving nutritional supplementation and muscular hypertrophy, and c) discuss research limitations and controversial issues in literature. Eight researchers with a relevant history of publications in this area were invited to answer six questions. Five researchers answered the Editor's invitation. After answering the questions, the researchers received responses from other participants following the blind system. Therefore, the researchers had a chance to discuss controversial points. Overall, despite the limitations and controversy in the literature, there was a consensus on the answers given by the researchers.
summary: Differences in protein requirements for athletes and nonathletes, and different types of athletes (i.e., endurance vs. strength/power) are well acknowledged. This has led many athletes to use protein supplements as a means of achieving required protein intakes. Recent research has begun to examine the importance of protein timing. Specifically, does it make a difference when the protein is ingested in regards to augmenting the acute physiological response to a training session or in enhancing recovery from exercise. This review focuses on the timing of protein intake and its effects on skeletal muscle remodeling.
(C) 2007 National Strength and Conditioning Association
In order to stimulate further adaptation toward a specific training goal(s), progression in the type of resistance training protocol used is necessary. The optimal characteristics of strength-specific programs include the use of both concentric and eccentric muscle actions and the performance of both single- and multiple-joint exercises. It is also recommended that the strength program sequence exercises to optimize the quality of the exercise intensity (large before small muscle group exercises, multiple-joint exercises before single-joint exercises, and higher intensity before lower intensity exercises). For initial resistances, it is recommended that loads corresponding to 8-12 repetition maximum (RM) be used in novice training. For intermediate to advanced training, it is recommended that individuals use a wider loading range, from 1-12 RM in a periodized fashion, with eventual emphasis on heavy loading (1-6 RM) using at least 3-min rest periods between sets performed at a moderate contraction velocity (1-2 s concentric, 1-2 s eccentric). When training at a specific RM load, it is recommended that 2-10% increase in load be applied when the individual can perform the current workload for one to two repetitions over the desired number. The recommendation for training frequency is 2-3 d·wk-1 for novice and intermediate training and 4-5 d·wk-1 for advanced training. Similar program designs are recommended for hypertrophy training with respect to exercise selection and frequency. For loading, it is recommended that loads corresponding to 1-12 RM be used in periodized fashion, with emphasis on the 6-12 RM zone using 1- to 2-min rest periods between sets at a moderate velocity. Higher volume, multiple-set programs are recommended for maximizing hypertrophy. Progression in power training entails two general loading strategies: 1) strength training, and 2) use of light loads (30-60% of 1 RM) performed at a fast contraction velocity with 2-3 min of rest between sets for multiple sets per exercise. It is also recommended that emphasis be placed on multiple-joint exercises, especially those involving the total body. For local muscular endurance training, it is recommended that light to moderate loads (40-60% of 1 RM) be performed for high repetitions (> 15) using short rest periods (< 90 s). In the interpretation of this position stand, as with prior ones, the recommendations should be viewed in context of the individual's target goals, physical capacity, and training status.
This randomized double-blind cross-over study assessed protein (PRO) requirements during the early stages of intensive bodybuilding training and determined whether supplemental PRO intake (PROIN) enhanced muscle mass/strength gains. Twelve men [22.4 +/- 2.4 (SD) yr] received an isoenergetic PRO (total PROIN 2.62 g.kg-1.day-1) or carbohydrate (CHO; total PROIN 1.35 g.kg-1.day-1) supplement for 1 mo each during intensive (1.5 h/day, 6 days/wk) weight training. On the basis of 3-day nitrogen balance (NBAL) measurements after 3.5 wk on each treatment (8.9 +/- 4.2 and -3.4 +/- 1.9 g N/day, respectively), the PROIN necessary for zero NBAL (requirement) was 1.4-1.5 g.kg-1.day-1. The recommended intake (requirement + 2 SD) was 1.6-1.7 g.kg-1.day-1. However, strength (voluntary and electrically evoked) and muscle mass [density, creatinine excretion, muscle area (computer axial tomography scan), and biceps N content] gains were not different between diet treatments. These data indicate that, during the early stages of intensive bodybuilding training, PRO needs are approximately 100% greater than current recommendations but that PROIN increases from 1.35 to 2.62 g.kg-1.day-1 do not enhance muscle mass/strength gains, at least during the 1st mo of training. Whether differential gains would occur with longer training remains to be determined.
To examine endogenous anabolic hormonal responses to two different types of heavy resistance exercise protocols (HREPs), eight male and eight female subjects performed two randomly assigned protocols (i.e. P-1 and P-2) on separate days. Each protocol consisted of eight identically ordered exercises carefully designed to control for load, rest period length, and total work (J) effects. P-1 utilized a 5 RM load, 3-min rest periods and had lower total work than P-2. P-2 utilized a 10 RM load, 1-min rest periods and had a higher total work than P-1. Whole blood lactate and serum glucose, human growth hormone (hGH), testosterone (T), and somatomedin-C [SM-C] (i.e. insulin-like growth factor 1, IGF-1) were determined pre-exercise, mid-exercise (i.e. after 4 of the 8 exercises), and at 0, 5, 15, 30, and 60 min post-exercise. Males demonstrated significant (p less than 0.05) increases above rest in serum T values, and all serum concentrations were greater than corresponding female values. Growth hormone increases in both males and females following the P-2 HREP were significantly greater at all time points than corresponding P-1 values. Females exhibited significantly higher pre-exercise hGH levels compared to males. The P-1 exercise protocol did not result in any hGH increases in females. SM-C demonstrated random significant increases above rest in both males and females in response to both HREPs.(ABSTRACT TRUNCATED AT 250 WORDS)
To examine endogenous anabolic hormone and growth factor responses to various heavy resistance exercise protocols (HREPs), nine male subjects performed each of six randomly assigned HREPs, which consisted of identically ordered exercises carefully designed to control for load [5 vs. 10 repetitions maximum (RM)], rest period length (1 vs. 3 min), and total work effects. Serum human growth hormone (hGH), testosterone (T), somatomedin-C (SM-C), glucose, and whole blood lactate (HLa) concentrations were determined preexercise, midexercise (i.e., after 4 of 8 exercises), and at 0, 5, 15, 30, 60, 90, and 120 min postexercise. All HREPs produced significant (P less than 0.05) temporal increases in serum T concentrations, although the magnitude and time point of occurrence above resting values varied across HREPs. No differences were observed for T when integrated areas under the curve (AUCs) were compared. Although not all HREPs produced increases in serum hGH, the highest responses were observed consequent to the H10/1 exercise protocol (high total work, 1 min rest, 10-RM load) for both temporal and time integrated (AUC) responses. The pattern of SM-C increases varied among HREPs and did not consistently follow hGH changes. Whereas temporal changes were observed, no integrated time (AUC) differences between exercise protocols occurred. These data indicate that the release patterns (temporal or time integrated) observed are complex functions of the type of HREPs utilized and the physiological mechanisms involved with determining peripheral circulatory concentrations (e.g., clearance rates, transport, receptor binding). All HREPs may not affect muscle and connective tissue growth in the same manner because of possible differences in hormonal and growth factor release.
Effects of endurance training on O2 transport and on iron status are well documented in the literature. Only a few data are available concerning the consequences of strenuous anaerobic muscular exercise on red cell function. This study was performed to test the influence of strength training alone on parameters of red cell O2 transport and iron status. Twelve healthy untrained males participated in a strength-training programme of 2-h sessions four times a week lasting 6 weeks. After 6 weeks a small but significant reduction of haemoglobin (Hb; -5.4 g.l-1) was found (p less than 0.05). Mean red cell volume did not change, but a pronounced decrease of mean cell Hb concentration (from 329.2 g.l-1, SE 2.5 to 309.8 g.l-1, SE 1.2; p less than 0.001) and mean corpuscular Hb (from 29.6 pg, SE 0.4 to 27.7 pg, SE 0.3; p less than 0.01) was observed. Serum ferritin decreased significantly by 35% (p less than 0.01); transferrin, serum iron and iron saturation of transferrin were unaltered. Serum haptoglobin concentration was diminished significantly by 30.5% (p less than 0.01). The reticulocyte count had already increased after 3 weeks of training (p less than 0.05) and remained elevated during the following weeks. Strength training had no significant influence on the O2 partial pressure at which Hb under standard conditions was 50% saturated, red cell 2,3-diphosphoglycerate and ATP concentration as well as on erythrocytic glutamate-oxalacetate transaminase activity. The data demonstrate that mechanical stress of red cells due to the activation of large muscle masses led to increased intravascular haemolysis, accompanied by a slightly elevated erythropoiesis, which had no detectable influence on Hb-O2 affinity. Training caused an initial depletion of body iron stores (prelatent iron deficiency). Although Hb had decreased by the end of the training phase a true "sports anaemia" could not be detected.
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.
In this study, five men exercised the knee extensor muscles of one leg for 60 min (71 +/- 2% maximal work capacity) with and without (control) an oral supplement (77 mg/kg) of branched-chain amino acids (BCAA). BCAA supplementation resulted in a doubling (P < 0.05) of the arterial BCAA levels before exercise (339 +/- 15 vs. 822 +/- 86 microM). During the 60 min of exercise, the total release of BCAA was 68 +/- 93 vs. 816 +/- 198 mumol/kg (P < 0.05) for the BCAA and control trials, respectively. The intramuscular BCAA concentrations were higher (P < 0.05) for the BCAA trial and remained higher (P < 0.05) throughout exercise. In both trials, substantial quantities of NH3 were released, and when NH3 production equivalent to IMP accumulation was subtracted the net NH3 production was 1,112 +/- 279 and 1,670 +/- 245 mumol/kg (P < 0.05) for the control and BCAA trials, respectively. In contrast, the release of the essential amino acids (EAA) was much lower for the BCAA than the control trial (P < 0.05). When the BCAA were subtracted from the EAA (EAA-BCAA), the total release of EAA minus BCAA was lower (P < 0.05) for the BCAA (531 +/- 70 mumol/kg) than the control (924 +/- 148 mumol/kg) trial. These data suggest that BCAA supplementation results in significantly greater muscle NH3 production during exercise. Furthermore, the increased intramuscular and arterial BCAA levels before and during exercise result in a suppression of endogenous muscle protein breakdown during exercise.
The purpose of this study was to examine the effects of a heavy-resistance exercise protocol known to dramatically elevate immunoreactive growth hormone (GH) on circulating insulin-like growth factor I (IGF-I) after the exercise stimulus. Seven men (23.1 +/- 2.4 yr) volunteered to participate in this study. Each subject was asked to perform an eight-station heavy-resistance exercise protocol consisting of 3 sets of 10 repetition maximum resistances with 1-min rest between sets and exercises followed by a recovery day. In addition, a control day followed a nonexercise day to provide baseline data. Pre- and postexercise (0, 15, and 30 min) blood samples were obtained and analyzed for lactate, creatinine kinase, GH, and IGF-I. Postexercise values for lactate and GH were significantly (P < 0.05) elevated above preexercise and resting baseline values. The highest mean GH concentration after the heavy-resistance exercise protocol was 23.8 +/- 11.8 micrograms/l, observed at the immediate postexercise time point. Significant increases in creatine kinase were observed after the exercise protocol and during the recovery day. No significant relationships were observed between creatine kinase and IGF-I concentrations. No significant changes in serum IGF-I concentrations were observed with acute exercise or between the recovery and control days. Thus, these data demonstrate that a high-intensity bout of heavy-resistance exercise that increases circulating GH did not appear to affect IGF-I concentrations over a 24-h recovery period in recreationally strength-trained and healthy young men.
In the present prospective longitudinal study 17 male endurance trained athletes (cyclists and triathletes; age 23.4+/-6.7 years, VO2max 61.2+/-7.5 ml x min(-1) x kg(-1); means+/-SD) were investigated both during a state of overtraining syndrome (OT: N=15), mainly induced by an increase of exercise intensity, as well as several times in a state of regular physical ability (NS: N=62). Cycle-ergometric and psychological data were compared for a period of approximately 19 months. On 2 separate days, each subject performed a maximum incremental graded exercise, two anaerobic tests (10 s and 30 s) as well as a short-endurance "stress test" with the intensity of 110% of the individual anaerobic threshold until volitional exhaustion. The mood state was recorded by a psychological questionnaire including 40 basic items. During OT the submaximal lactate concentrations were slightly decreased. The performance of the 10 s- and 30 s-tests was unaffected. In contrast, the duration of the "stress test" decreased significantly by approximately 27% during OT compared to the individual NS. The submaximal oxygen uptake measured during the incremental graded exercise was slightly higher during OT as compared to NS, whereas the submaximal and maximal respiratory exchange ratio, maximal heart rate and maximal lactate concentrations were decreased. At the 10th minute of the "stress test", ammonia tended to be increased during OT (P=0.048). The parameters of mood state at rest as well as the subjective rating of perceived exertion during exercise were significantly impaired during OT. In conclusion, the results indicate a decreased intramuscular utilization of carbohydrates with diminished maximal anaerobic lactacid energy supply during OT. Neither the lactate-performance relationship during incremental graded exercise nor the anaerobic alactacid performance showed alterations. The duration of the short-endurance "stress test", the maximal lactate concentration of the incremental graded exercise as well as the altered mood profile turned out to be the most sensitive parameters for the diagnosis of OT.
Nine resistance-trained men consumed either a protein-carbohydrate supplement or placebo for 1 wk in a crossover design separated by 7 days. The last 3 days of each treatment, subjects performed resistance exercise. The supplement was consumed 2 h before and immediately after the workout, and blood was obtained before and after exercise (0, 15, 30, 45, and 60 min postexercise). Lactate, growth hormone, and testosterone were significantly (P </= 0.05) elevated immediately postexercise. The lactate response was significantly lower during supplementation on days 2 and 3. Growth hormone and prolactin responses on day 1 were significantly higher during supplementation. After exercise, testosterone declined below resting values during supplementation. Cortisol decreased immediately postexercise on day 1; the response was diminished on days 2 and 3. Glucose and insulin were significantly elevated by 30 min during supplementation and remained stable during placebo. Insulin-like growth factor-I was higher during supplementation on days 2 and 3. These data indicate that protein-carbohydrate supplementation before and after training can alter the metabolic and hormonal responses to consecutive days of heavy-resistance exercise.
This study was designed to determine the ability of leucine to enhance muscle recovery after exercise. Male rats (200 g) were divided into five groups: sedentary, food-deprived (SF); exercised, food-deprived (EF); exercised, fed a carbohydrate meal (EC); exercised, fed a leucine meal (EL); and exercised, fed a combination of carbohydrate and leucine (ECL). All meals were administered by oral gavage immediately following exercise. EC and ECL meals were isocaloric and provided 15% of daily energy intake. EL and ECL meals each provided 270 mg leucine. Rats ran on a motor-driven treadmill for 2 h at 36 m/min and were killed 1 h postexercise. Plasma glucose and insulin were measured, and the gastrocnemius and plantaris muscles were excised as a unit to determine glycogen levels and the fractional rate of skeletal muscle protein synthesis (Ks). Exercise did not alter plasma glucose or insulin. In contrast, prolonged exercise reduced muscle glycogen (-51%) and Ks (-18%). Refeeding a combination of carbohydrate and leucine increased plasma insulin relative to the EF and SF groups and produced complete recovery of muscle Ks and glycogen to values not different from those in SF rats. Feeding leucine alone restored Ks to that in the SF group without affecting plasma glucose or insulin concentrations. Feeding carbohydrate alone enhanced the rate of glycogen repletion compared to the EF group, concomitant with increases in plasma glucose and insulin. The degree of glycogen recovery correlated with plasma insulin concentrations (r = 0.58, P < 0.05). These data suggest that leucine stimulates muscle protein synthesis following exercise, independent of increased plasma insulin. This is the first demonstration that orally administered leucine stimulates recovery of skeletal muscle protein synthesis after exercise.
We have previously quantified the extent of myofibrillar disruption which occurs following an acute bout of resistance exercise in untrained men, however the response of well-trained subjects is not known. We therefore recruited six strength-trained men, who ceased training for 5 days and then performed 8 sets of 8 uni-lateral repetitions, using a load equivalent to 80% of their concentric (Con) 1-repetition maximum. One arm performed only Con actions by lifting the weight and the other arm performed only eccentric actions (Ecc) by lowering it. Needle biopsy samples were obtained from biceps brachii of each arm approximately 21 h following exercise, and at baseline (i.e., after 5 days without training), and subsequently analyzed using electron microscopy to quantify myofibrillar disruption. A greater (P < or = 0.05) proportion of disrupted fibres was found in the Ecc arm (45 +/- 11%) compared with baseline values (4 +/- 2%), whereas fibre disruption in the Con arm (27 +/- 4%) was not different (P > 0.05) from baseline values. The proportion of disrupted fibres and the magnitude of disruption (quantified by sarcomere counting) was considerably less severe than previously observed in untrained subjects after an identical exercise bout. Mixed muscle protein synthesis, assessed from approximately 21-29 h post-exercise, was not different between the Con- and Ecc-exercised arms. We conclude that the Ecc phase of resistance exercise is most disruptive to skeletal muscle and that training attenuates the severity of this effect. Moreover, it appears that fibre disruption induced by habitual weightlifting exercise is essentially repaired after 5 days of inactivity in trained men.
In order to stimulate further adaptation toward a specific training goal(s), progression in the type of resistance training protocol used is necessary. The optimal characteristics of strength-specific programs include the use of both concentric and eccentric muscle actions and the performance of both single- and multiple-joint exercises. It is also recommended that the strength program sequence exercises to optimize the quality of the exercise intensity (large before small muscle group exercises, multiple-joint exercises before single-joint exercises, and higher intensity before lower intensity exercises). For initial resistances, it is recommended that loads corresponding to 8-12 repetition maximum (RM) be used in novice training. For intermediate to advanced training, it is recommended that individuals use a wider loading range, from 1-12 RM in a periodized fashion, with eventual emphasis on heavy loading (1-6 RM) using at least 3-min rest periods between sets performed at a moderate contraction velocity (1-2 s concentric, 1-2 s eccentric). When training at a specific RM load, it is recommended that 2-10% increase in load be applied when the individual can perform the current workload for one to two repetitions over the desired number. The recommendation for training frequency is 2-3 d x wk(-1) for novice and intermediate training and 4-5 d x wk(-1) for advanced training. Similar program designs are recommended for hypertrophy training with respect to exercise selection and frequency. For loading, it is recommended that loads corresponding to 1-12 RM be used in periodized fashion, with emphasis on the 6-12 RM zone using 1- to 2-min rest periods between sets at a moderate velocity. Higher volume, multiple-set programs are recommended for maximizing hypertrophy. Progression in power training entails two general loading strategies: 1) strength training, and 2) use of light loads (30-60% of 1 RM) performed at a fast contraction velocity with 2-3 min of rest between sets for multiple sets per exercise. It is also recommended that emphasis be placed on multiple-joint exercises, especially those involving the total body. For local muscular endurance training, it is recommended that light to moderate loads (40-60% of 1 RM) be performed for high repetitions (> 15) using short rest periods (< 90 s). In the interpretation of this position stand, as with prior ones, the recommendations should be viewed in context of the individual's target goals, physical capacity, and training status.
This study tests the hypothesis that a dose of 6 g of orally administered essential amino acids (EAAs) stimulates net muscle protein balance in healthy volunteers when consumed 1 and 2 h after resistance exercise. Subjects received a primed constant infusion of L-[(2)H(5)]phenylalanine and L-[1-(13)C]leucine. Samples from femoral artery and vein and biopsies from vastus lateralis were obtained. Arterial EAA concentrations increased severalfold after drinks. Net muscle protein balance (NB) increased proportionally more than arterial AA concentrations in response to drinks, and it returned rapidly to basal values when AA concentrations decreased. Area under the curve for net phenylalanine uptake above basal value was similar for the first hour after each drink (67 +/- 17 vs. 77 +/- 20 mg/leg, respectively). Because the NB response was double the response to two doses of a mixture of 3 g of EAA + 3 g of nonessential AA (NEAA) (14), we conclude that NEAA are not necessary for stimulation of NB and that there is a dose-dependent effect of EAA ingestion on muscle protein synthesis.
Incubation of isolated rat soleus and EDL muscles in the presence of 10 mM leucine resulted in a decreased proteolytic rate as measured by the release of tyrosine into the incubation medium. The effect of this branched‐chain amino acid (BCAA) is associated with a decreased activity of the lysosomal proteases and a decreased expression of the genes of the ATP‐ubiquitin–dependent proteolysis (ubiquitin and C8). Incubation of muscles in the presence of actinomycin D revealed that the effects of the amino acid can be accounted for by an inhibition of the transcription rate. The presence of leucine did not influence the gene expression of other nonlysosomal (m‐calpain) and lysosomal (cathepsin B) proteolytic systems. It is concluded that the well‐known effect of BCAA on muscle proteolysis is mediated, in the short term, by the inhibition of lysosomal proteolysis. In a longer period, based on the inhibition of gene transcription observed, an involvement of the ATP‐dependent proteolytic system is also likely to occur. J. Cell. Physiol. 184:380–384, 2000. © 2000 Wiley‐Liss, Inc.
Resistance training is popular and has been shown to be a safe and effective way of improving muscular fitness. With the popularity of resistance training came the need for scientists to investigate its utility in various types of individuals during an acute bout of resistance exercise and the subsequent adaptations during long-term resistance training. Current research has shown the need for variation in program design to produce continued gains in fitness and performance. Periodized resistance training programs have been shown to be effective during short-term and long-term training periods, while reducing the risk of overtraining. Several variables may be manipulated to produce an adaptation specific to training goals. Training variation is the most effective way to produce continued improvements during long-term resistance training.
The multitude of publications regarding overtraining syndrome (OTS or ‘staleness’) or the short-term ‘over-reaching’ and the severity of consequences for the athlete are in sharp contrast with the limited availability of valid diagnostic tools. Ergometric tests may reveal a decrement in sport-specific performance if they are maximal tests until exhaustion. Overtrained athletes usually present an impaired anaerobic lactacid performance and a reduced time-to-exhaustion in standardised high-intensity endurance exercise accompanied by a small decrease in the maximum heart rate. Lactate levels are also slightly lowered during submaximal performance and this results in a slightly increased anaerobic threshold. A reduced respiratory exchange ratio during exercise still deserves further investigation. A deterioration of the mood state and typical subjective complaints (‘heavy legs’, sleep disorders) represent sensitive markers, however, they may be manipulated. Although measurements at rest of selected blood markers such as urea, uric acid, ammonia, enzymes (creatine kinase activity) or hormones including the ratio between (free) serum testosterone and cortisol, may serve to reveal circumstances which, for the long term, impair the exercise performance, they are not useful in the diagnosis of established OTS. The nocturnal urinary catecholamine excretion and the decrease in the maximum exercise-induced rise in pituitary hormones, especially adrenocorticotropic hormone and growth hormone, and, to a lesser degree, in cortisol and free plasma catecholamines, often provide interesting diagnostic information, but hormone measurements are less suitable in practical application. From a critical review of the existing overtraining research it must be concluded that there has been little improvement in recent years in the tools available for the diagnosis of OTS.
• The aim of this study was to describe the time course of the response of human muscle protein synthesis (MPS) to a square wave increase in availability of amino acids (AAs) in plasma. We investigated the responses of quadriceps MPS to a ≈1.7-fold increase in plasma AA concentrations using an intravenous infusion of 162 mg (kg body weight)−1 h−1 of mixed AAs. MPS was estimated from D3-leucine labelling in protein after a primed, constant intravenous infusion of D3-ketoisocaproate, increased appropriately during AA infusion. • Muscle was separated into myofibrillar, sarcoplasmic and mitochondrial fractions. MPS, both of mixed muscle and of fractions, was estimated during a basal period (2.5 h) and at 0.5-4 h intervals for 6 h of AA infusion. • Rates of mixed MPS were not significantly different from basal (0.076 ± 0.008 % h−1) in the first 0.5 h of AA infusion but then rose rapidly to a peak after 2 h of ≈2.8 times the basal value. Thereafter, rates declined rapidly to the basal value. All muscle fractions showed a similar pattern. • The results suggest that MPS responds rapidly to increased availability of AAs but is then inhibited, despite continued AA availability. These results suggest that the fed state accretion of muscle protein may be limited by a metabolic mechanism whenever the requirement for substrate for protein synthesis is exceeded.
Testprotokolle, Testbeschreibungen unterschiedlichster Krafttests
The purpose of this study was to examine the time-course and relationships of technetium-99m (99mTc) neutrophils in muscle, interleukin-6 (IL-6), myosin heavy chain fragments (MHC), eccentric torque, and delayed onset muscle
soreness (DOMS) following eccentric exercise in humans. Twelve male subjects completed a pre-test DOMS questionnaire, performed
a strength test and had 100 ml blood withdrawn for analysis of plasma IL-6 and MHC content. The neutrophils were separated,
labelled with 99mTc, and re-infused into the subjects immediately before the exercise. Following 300 eccentric repetitions of the right quadriceps
muscles on an isokinetic dynamometer, the subjects had 10 ml of blood withdrawn and repeated the eccentric torque exercise
tests and DOMS questionnaire at 0, 2, 4, 6, 20, 24, 48, 72 h, and 6 and 9 days. Bilateral images of the quadriceps muscles
were taken at 2, 4, and 6 h. Computer analysis of regions of interest was used to determine the average count per pixel. The
99mTc neutrophils and IL-6 increased up to 6 h post-exercise (P < 0.05). The neutrophils were greater in the exercised muscle than the non-exercised muscle (P < 0.01). The DOMS was increased from 0 to 48 h, eccentric torque decreased from 2 to 24 h, and MHC peaked at 72 h post-exercise
(P < 0.001). Significant relationships were found between IL-6 at 2 h and DOMS at 24 h post-exercise (r=0.68) and assessment of the magnitude of change between IL-6 and MHC (r=0.66). These findings suggest a relationship between damage to the contractile proteins and inflammation, and that DOMS is
associated with inflammation but not with muscle damage.
Training-induced adaptations in the endocrine system and strength development were investigated in nine male strength athletes during two separate 3-week intensive strength training periods. The overall amount of training in the periods was maintained at the same level. In both cases the training in the first 2 weeks was very intensive: this was followed by a 3rd week when the overall amount of training was greatly decreased. The two training periods differed only in that training period I included one daily session, while during the first 2 weeks of period II the same amount of training was divided between two daily sessions. In general, only slight and statistically insignificant changes occurred during training period I in mean concentrations of serum hormones examined or sex hormone-binding globulin as well as in maximal isometric leg extensor force. However, during training period II after 2 weeks of intensive strength training a significant decrease (P less than 0.05) was observed in serum free testosterone concentration [from 98.4 (SD 24.5) to 83.8 (SD 14.7) pmol.l-1] during the subsequent week of reduced training. No change in the concentration of total testosterone was observed. This training phase was also accompanied by significant increases (P less than 0.05) in serum luteinizing hormone (LH) and cortisol concentrations. After 2 successive days of rest serum free testosterone and LH returned to (P less than 0.05) their basal concentrations. Training period II led also to a significant increase (P less than 0.05) [from 3942 (SD 767) to 4151 (SD 926) N] in maximal force.(ABSTRACT TRUNCATED AT 250 WORDS)
To find out to what extent body composition affects glucose tolerance, blood glucose (BG) and insulin (IRI) responses to a 100-g oral glucose tolerance test (OGTT) were compared in 10 male body builders, 11 untrained lean control subjects, and 11 mildly obese men, all of similar age (19-35 years). In comparison with the remaining two groups, the body builders had the lowest percentage of fat, although their lean body mass (LBM) in absolute terms did not differ from that in obese subjects. Both BG and IRI concentrations during the OGTT were the lowest in body builders, medium in controls, and the highest in obese men. The differences in glucose tolerance between the groups were also demonstrated by comparison of the subjects' BG levels during the OGTT with the respective mean BG values obtained in a reference group of 42 healthy nonobese men aged from 20 to 55 years.
The data indicate that body builders show better glucose tolerance and improved insulin action in comparison with untrained, nonobese subjects of similar age and body weight. Lean body mass in absolute terms cannot, however, be considered as a sole determinant of the insulin action in the body since in mildly obese subjects glucose tolerance was considerably reduced in spite of the fact that their LBM was similar to that in body builders. Either muscle hypertrophy or reduced adiposity may account for the beneficial effects of body building on glucose metabolism.
The purpose of this study was to determine whether high intensity weight lifting exercise produces elevations of urinary 3-methylhistidine (3-MH), serum creatine kinase activity (CK), and serum myoglobin concentration (MY), and whether trained weight lifters differed in such responses when compared to a group of untrained subjects. Ten experienced male weight lifters (EWL) and seven untrained male subjects (IWL) performed three sets of six weight lifting exercises at 70%-80% of 1 RM. All subjects consumed a meat-free diet. The 3-MH:creatinine (3-MH:CR) values decreased 24 h and 48 h following exercise (P less than 0.05). The 12-h and 24-h postexercise CK response and the 12-h postexercise MY response increased for both EWL and IWL (P less than 0.05). However, EWL had a lower 24-h postexercise CK response and lower 12-h and 24-h postexercise MY responses compared to IWL (P less than 0.05). Within 48 h following weight lifting exercise, skeletal muscle protein degradation (as assessed by 3-MH:CR values) decreased regardless of prior training experience whereas skeletal muscle tissue damage (as assessed by CK and MY responses) increased. However, prior weight lifting training appeared to diminish the extent of muscle tissue damage.