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Effect of protein-supplement timing on strength, power, and body-composition Changes in resistance-trained men
Abstract
The effect of 10 wk of protein-supplement timing on strength, power, and body composition was examined in 33 resistance-trained men. Participants were randomly assigned to a protein supplement either provided in the morning and evening (n = 13) or provided immediately before and immediately after workouts (n = 13). In addition, 7 participants agreed to serve as a control group and did not use any protein or other nutritional supplement. During each testing session participants were assessed for strength (one-repetition-maximum [1RM] bench press and squat), power (5 repetitions performed at 80% of 1RM in both the bench press and the squat), and body composition. A significant main effect for all 3 groups in strength improvement was seen in 1RM bench press (120.6 +/- 20.5 kg vs. 125.4 +/- 16.7 at Week 0 and Week 10 testing, respectively) and 1RM squat (154.5 +/- 28.4 kg vs. 169.0 +/- 25.5 at Week 0 and Week 10 testing, respectively). However, no significant between-groups interactions were seen in 1RM squat or 1RM bench press. Significant main effects were also seen in both upper and lower body peak and mean power, but no significant differences were seen between groups. No changes in body mass or percent body fat were seen in any of the groups. Results indicate that the time of protein-supplement ingestion in resistance-trained athletes during a 10-wk training program does not provide any added benefit to strength, power, or body-composition changes.
... Also, the protein-amino acid group experienced a significant increase in squat jump height while no changes occurred in the carbohydrate group. Using a similar study design, Hoffman and colleagues [110] had collegiate football players who had been regularly performing resistance-training ingest 42 g of hydrolyzed collagen protein either immediately before and immediately after exercise, or in the morning and evening over the course of ten weeks of resistance training. In this study, the timing of protein intake did not impact changes in strength, power and body composition experienced from the resistance-training program. ...
... While a large number of acute exercise and nu- trient administration studies have provided multiple mechanistic explanations for why post-exercise feeding may be advantageous [115][116][117][118][119], other studies suggest this study model may not be directly reflective of adapta- tions seen over the course of several weeks or months [120]. As highlighted throughout the pre-exercise protein timing section, the majority of studies that have examined some aspect of post-exercise protein timing have done so while also administering an identical dose of protein immediately before each workout [16,109,110,121]. Of these studies, protein [109] or carbohydrate + protein [16] consumption immediately before and immediately after resistance exercise has been shown to positively affect resistance training adaptations. ...
... Of these studies, protein [109] or carbohydrate + protein [16] consumption immediately before and immediately after resistance exercise has been shown to positively affect resistance training adaptations. These results, however, are not universal as Hoffman et al. [110] reported no impact of timing when 42 g of hydrolyzed collagen protein was ingested before and after several weeks of resistance ti- ming. Of note, participants in the Hoffman study were all highly-trained collegiate athletes who reported consuming a hypoenergetic diet. ...
Position statement: The International Society of Sports Nutrition (ISSN) provides an objective and critical review regarding the timing of macronutrients in reference to healthy, exercising adults and in particular highly trained individuals on exercise performance and body composition. The following points summarize the position of the ISSN: 1. Nutrient timing incorporates the use of methodical planning and eating of whole foods, fortified foods and dietary supplements. The timing of energy intake and the ratio of certain ingested macronutrients may enhance recovery and tissue repair, augment muscle protein synthesis (MPS), and improve mood states following high-volume or intense exercise.
... After 10 weeks of progressive resistance exercise, significant increases in lean body mass and hypertrophy of type II fibers were seen when the supplement was timed around the exercise bout as compared to delaying consumption. On the other hand,Hoffman et al. (2009)showed no significant differences in total body mass or lean body mass when resistance-trained men with an average of 5.9 years lifting experience consumed a supplement containing 42 g protein and 2 g carbohydrate immediately before and after resistance exercise versus in the early morning and late evening over a 10-week period. Therefore, the purpose of this study was to investigate muscular adaptations in response to an equal dose of protein consumed either immediately pre-versus post-resistance exercise in well-trained men. ...
... Longitudinal studies on the topic of protein timing are conflicting. A number of studies have shown beneficial effects of post-workout protein timing on muscle strength and size (Esmarck et al., 2001;Cribb & Hayes, 2006;Willoughby, Stout & Wilborn, 2007) while others have not (Hoffman et al., 2009;Candow et al., 2006;Verdijk et al., 2009). A recent meta-analysis by Schoenfeld, Aragon & Krieger (2013) found that consuming protein within 1 h post-resistance exercise had a small but significant effect on increasing muscle hypertrophy compared to delaying consumption by at least 2 h. ...
... After 10 weeks of progressive resistance exercise, significant increases in lean body mass and hypertrophy of type II fibers were seen when the supplement was timed around the exercise bout as compared to delaying consumption. On the other hand, Hoffman et al. (2009) showed no significant differences in total body mass or lean body mass when resistance-trained men with an average of 5.9 years lifting experience consumed a supplement containing 42 g protein and 2 g carbohydrate immediately before and after resistance exercise versus in the early morning and late evening over a 10-week period. ...
The purpose of this study was to test the anabolic window theory by investigating muscle strength, hypertrophy, and body composition changes in response to an equal dose of protein consumed either immediately pre- versus post-resistance training (RT) in trained men. Subjects were 21 resistance-trained men (>1 year RT experience) recruited from a university population. After baseline testing, participants were randomly assigned to 1 of 2 experimental groups: a group that consumed a supplement containing 25 g protein and 1 g carbohydrate immediately prior to exercise (PRE-SUPP) ( n = 9) or a group that consumed the same supplement immediately post-exercise (POST-SUPP) ( n = 12). The RT protocol consisted of three weekly sessions performed on non-consecutive days for 10 weeks. A total-body routine was employed with three sets of 8–12 repetitions for each exercise. Results showed that pre- and post-workout protein consumption had similar effects on all measures studied ( p > 0.05). These findings refute the contention of a narrow post-exercise anabolic window to maximize the muscular response and instead lends support to the theory that the interval for protein intake may be as wide as several hours or perhaps more after a training bout depending on when the pre-workout meal was consumed.
... Although the importance of protein supplementation in close proximity to the exercise stimulus for enhancing muscle protein synthesis in trained participants has been well documented [88, 99], there has been only one study that has examined the timing of protein ingestion together with metrics of muscle strength for resistance-trained participants. Hoffman et al. [112] compared the effects of protein supplementation provided in the morning and evening or immediately before and after workouts, which occurred four times weekly for 10 weeks. Supplementation also occurred at the same time of day during the three non-training days and there was a control group that did not receive supplementation . ...
... The validity of a study is reduced if total caloric and protein intake are not adequately reported [89, 91, 119] or in cases where changes in diet are not consistent or do not reflect the additional supplements (i.e., protein or carbohydrate) provided to different groups of participants [81, 104, 106, 107, 111]. It should also be noted that in the studies reviewed above, mean normal daily protein intake for Table 5A summary of the performance outcomes for the effects of protein and/or carbohydrate supplements on aerobic and anaerobic power AM morning, BM body mass, CHO carbohydrate, EAA essential amino acid, HR max maximal heart rate, IKST isokinetic strength, LBM lean body mass, PLA placebo, PRO protein, RM repetition maximum, TTE time to exhaustion, _ VO 2max maximal aerobic power participants varied considerably, from slightly less than 1 to well over 2 gÁkg -1 per day but few studies reported the nitrogen balance of their participants [72, 90, 96, 112]. Since protein supplements may be more effective when participants are in an otherwise negative nitrogen balance due to their normal diet [121, 122], the benefits of a diet that is typically high in protein may offset any further advantage additional protein supplements might provide. ...
... In these situations, ingestion of the supplement in close proximity to the beginning or immediately following exercise may be more critical than the total dose provided throughout the day [57, 73, 123]. However, the only study that was conducted with resistance-trained participants and included metrics of performance failed to support this premise [112]. The mean total dose of protein supplement provided varied considerably among the studies reviewed from a low of 3 gÁday -1 of leucine [118] to over 100 gÁday -1 of whey or casein [107]. ...
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.
... West et al. (2011) identified that a rapid rate of appearance of amino acids in the blood as occurs following ingestion of amino acid supplements provides greater stimulation of mTOR and protein synthesis than slower rates of appearance that are seen following whole food consumption. Tipton, Elliott, Cree, Aarsland, Sanford, and Wolfe (2007), Hoffman, Ratamess, Tranchina, Rashti, Kang, and Faigenbaum (2009), and Cribb & Hayes (2006) report that protein synthesis in response to amino acids is greatest when consumed prior to or during the exercise session. Considering these effects of amino acid availability within the body it can be suggested that the provision of external sources of EAA and BCAA during the critical time period surround exercise is necessary to prevent muscle protein breakdown, produce new muscle synthesis, and facilitate muscular recovery and adaptation to the exercise stimulus. ...
... An ideal property of EAA and BCAA supplements is the ability to time ingestion around exercise to provide peak concentrations of amino acids in the blood when the contractioninduced signaling and potential for delivery of amino acids and subsequent incorporation into muscle protein is greatest (Tipton et al. 2007, Hoffman et al. 2009, and Cribb & Hayes 2006). Shimomura et al. (2006) found that a 5g mixture of BCAA produced elevated plasma concentrations of the BCAA within 15 minutes and reached peak values 30 minutes after ingestion. ...
... As discussed previously, there are beneficial effects of EAA and BCAA ingestion on cellular signaling, muscle protein synthesis, reductions in muscle damage, maintenance of and accelerated improvements in qualities of muscular strength during periods of high physical and metabolic stress, and preservation of lean muscle tissue during weight loss (Ratamess et al. 2003, Kraemer et al. 2006, Tipton et al. 2009, Pasiakos et al. 2011, Mourier et al. 1997, Hoffman et al. 2009, & Cribb & Hayes 2006). A further question for the efficacy of EAA and BCAA ingestion is whether these practices can produce improvements in performances during resistance training programs not utilizing overreaching, endurance, and interval training. ...
... These positive results were induced from dietary timing, which is very important to maximize the effect of dietary protein supplements. Hoffman and colleagues 38 had collegiate football players who had been regularly performing resistance-training ingest 42 g of hydrolyzed protein immediately before and after exercise over the course of 10 weeks of resistance training. In this study, the timing of the protein intake did not impact on the changes in strength, power, or body composition. ...
... These findings support that the ingestion of whey protein immediately before and immediately after workouts can promote improvements in strength and hypertrophy. Furthermore, since the subjects of Hoffman's study 38 were trained athletes, but the subjects of the present study were untrained, we can infer that athletes will need more protein than untrained individuals. A unique aspect of the present study was that supplementation only occurred on training days; this shows that it is an important to consume protein supplements at the optimal time in order to maximize the benefits. ...
Purpose:
The composition of protein supplements, the consumption timing immedi¬ately before and after resistance exercise training (RET), and the quantity of protein supplementation may be important factors for the im-provement of muscle mass and function. Although these factors should be considered comprehensively for effective improvement of muscular function in protein supplementation, relatively few studies have focused on this area. Therefore, this study was designed to investigate whether a protein blend supplement before and after resistance exercise for 12 weeks would be effective in increasing muscular function.
Methods:
In total, 18 participants were randomly assigned to a placebo (PLA) or protein blend supplement (PRO) group. All subjects followed the same training routine 3 times per week for 12 weeks, taking placebo or protein supplements immediately before and after each exercise session. The protein supplement consisted of 40 g of blend protein, including hydrolyzed whey protein. The RET consisted of lower body (barbell squat, dead lift, seated leg extension, and lying leg curl) and upper body (bench press, barbell rowing, preacher bench biceps curl, and dumbbell shoulder press) exercises. A repetition was defined as three sets of 10-12 times with 80% of one repetition maximum (1RM).
Results:
Although the PRO group had a lower protein intake in terms of total food intake than the PLA group, the mean changes in muscle circumference, strength, and exercise volume increased, especially at week 12, compared to the PLA group.
Conclusion:
These results suggest that the composition and timing of protein intake are more important than the total amount.
... In contrast to whey protein, supplements containing a predominance of casein protein, due to their slower rate of digestion and release kinetics allow for prolonged supply of amino acids for skeletal muscles [20,22,25]. Numerous studies have confirmed that the use of protein dietary supplements before and after exercise increases sports performance [23,28], affects muscle hypertrophy [19,21] and muscular power [18,19,28], and increases lean body mass [18,19,29]. Important supplements used immediately after and during the first 2 hours of recovery include carbohydrate-protein products that also affect the concentration of GH and I [8]. ...
... In contrast to whey protein, supplements containing a predominance of casein protein, due to their slower rate of digestion and release kinetics allow for prolonged supply of amino acids for skeletal muscles [20,22,25]. Numerous studies have confirmed that the use of protein dietary supplements before and after exercise increases sports performance [23,28], affects muscle hypertrophy [19,21] and muscular power [18,19,28], and increases lean body mass [18,19,29]. Important supplements used immediately after and during the first 2 hours of recovery include carbohydrate-protein products that also affect the concentration of GH and I [8]. ...
... Thus, it remains unclear whether training status influences the hypertrophic response to optimal dose (30 to 40 g) pre-or post-exercise, since muscle adaptations tend to be larger in novices [16].In young adults, Cribb and Hayes (2006) [22] showed that the protein supplement timing represents a simple but effective strategy to enhance the adaptations (strength and hypertrophy) that are desired from RT. On the other hand, Hoffman et al. (2009) [23] and Schoenfeld et al. (2017) [24] showed no significant differences in timing protein intake muscular adaptations in well-trained men. Thus, training status had not yet been tested in women and/or in the elderly. ...
... Thus, it remains unclear whether training status influences the hypertrophic response to optimal dose (30 to 40 g) pre-or post-exercise, since muscle adaptations tend to be larger in novices [16].In young adults, Cribb and Hayes (2006) [22] showed that the protein supplement timing represents a simple but effective strategy to enhance the adaptations (strength and hypertrophy) that are desired from RT. On the other hand, Hoffman et al. (2009) [23] and Schoenfeld et al. (2017) [24] showed no significant differences in timing protein intake muscular adaptations in well-trained men. Thus, training status had not yet been tested in women and/or in the elderly. ...
Aging is associated with sarcopenia and dynapenia, with both processes contributing to functional dependence and mortality in older adults. Resistance training (RT) and increased protein intake are strategies that may contribute to health improvements in older adults. Therefore, the aim was to investigate the effects of whey protein (WP) supplementation consumed either immediately pre- or post-RT on skeletal muscle mass (SMM), muscular strength, and functional capacity in pre-conditioned older women. Seventy older women participated in this investigation and were randomly assigned to one of three groups: whey protein pre-RT and placebo post-RT (WP-PLA, n = 24), placebo pre-RT and whey protein post-RT (PLA-WP, n = 23), and placebo pre- and post-RT (PLA-PLA, n = 23). Each group ingested 35 g of WP or PLA. The RT program was carried out over 12 weeks (three times per week; 3 × 8⁻12 repetition maximum). Body composition, muscular strength, functional capacity, and dietary intake were assessed pre- and post-intervention. Two-way analysis of covariance (ANCOVA) for repeated measures, with baseline scores as covariates were used for data analysis. A time vs. group interaction (p < 0.05) was observed with WP-PLA and PLA-WP presenting greater increases compared with PLA-PLA for SMM (WP-PLA = 3.4%; PLA-WP = 4.2%; PLA-PLA = 2.0%), strength (WP-PLA = 8.1%; PLA-WP = 8.3%; PLA-PLA = 7.0%), and the 10-m walk test (WP-PLA = −10.8%; PLA-WP = −11.8%; PLA-PLA = −4.3%). Whey protein supplementation was effective in promoting increases in SMM, muscular strength, and functional capacity in pre-conditioned older women, regardless of supplementation timing. This trial was registered at ClinicalTrials.gov: NCT03247192.
... Four studies included in this review did test the effect of protein supplementation timing proximate to, vs not proximate to, resistance training. 33,35,40,43 Three studies reported that the timing of protein supplementation did not differentially affect changes in lean mass, 33,40,43 while 1 reported that protein supplementation before and after resistance training promoted greater gains in lean mass than when the same protein supplement was consumed in the morning and evening. 35 Supplements containing mixtures of protein and creatine may be another potential limitation. ...
... Four studies included in this review did test the effect of protein supplementation timing proximate to, vs not proximate to, resistance training. 33,35,40,43 Three studies reported that the timing of protein supplementation did not differentially affect changes in lean mass, 33,40,43 while 1 reported that protein supplementation before and after resistance training promoted greater gains in lean mass than when the same protein supplement was consumed in the morning and evening. 35 Supplements containing mixtures of protein and creatine may be another potential limitation. ...
Context
The impact of timing the consumption of protein supplements in relation to meals on resistance training–induced changes in body composition has not been evaluated systematically.
Objective
The aim of this systematic review was to assess the effect of consuming protein supplements with meals, vs between meals, on resistance training–induced body composition changes in adults.
Data Sources
Studies published up to 2017 were identified with the PubMed, Scopus, Cochrane, and CINAHL databases.
Data Extraction
Two researchers independently screened 2077 abstracts for eligible randomized controlled trials of parallel design that prescribed a protein supplement and measured changes in body composition for a period of 6 weeks or more.
Results
In total, 34 randomized controlled trials with 59 intervention groups were included and qualitatively assessed. Of the intervention groups designated as consuming protein supplements with meals (n = 16) vs between meals (n = 43), 56% vs 72% showed an increase in body mass, 94% vs 90% showed an increase in lean mass, 87% vs 59% showed a reduction in fat mass, and 100% vs 84% showed an increase in the ratio of lean mass to fat mass over time, respectively.
Conclusions
Concurrently with resistance training, consuming protein supplements with meals, rather than between meals, may more effectively promote weight control and reduce fat mass without influencing improvements in lean mass.
... Although lower carbohydrate consumption is observed in dietary records, this type of behavior is not generalized for all weightlifters (Cabral et al., 2006). In general, protein supplements have been shown to improve physical performance before and after training (Hoffman et al., 2009;Josse et al., 2010).lean body mass (Cribb & Hayes 2006;Josse et al., 2010). ...
... body mass (Cribb & Hayes 2006;Josse et al., 2010). On the other hand, specific gains vary according to the type and amount of proteins (Hoffman et al., 2009;Andersen et al., 2005). While the usage rate of ergogenic products according to the educational level of female weightlifters is not changed, this ratio varies significantly between secondary school, high school and university graduates (Fischer's exact p value=.024, p<0.05) in males (Table 4). ...
Nutritional habits affect performance directly or indirectly in weight class included sports. The aim of this study was to compare the dietary habits of elite female and male weightlifters. After getting official records of athletes from Turkish Weightlifting Federation, a survey was conducted on several factors of the athletes such as weight class, education level, national and international success, income level, weight reduction condition, whether the athlete has knowledge about nutrition, fluid intake, dietary approach before competitions, and type of ergogenic usage. The correlation analyses were completed to determine the relationship between the groups. One-way ANOVA was used to compare the groups. Fischer’s exact tests were calculated again to compare the dietary preferences between different groups. Results of this study showed that lower income, weight category, lower age and level of education of male weightlifters negatively affect the performance. Male weightlifters underestimate the importance of fluid intake and they consumed different types of diets. The use of ergogenic products in female weightlifters was differentiated according to their education levels, weight classes and the competition category. Again, the international female weightlifters consumed more ergogenic substance than national level weightlifters. Both male and female weightlifters showed no significant correlations between the performance variables and all other conditions. It can be suggested that the socio-economic status and education level related to sport nutrition in weightlifters should be increased for enhancing of the weightlifting performance.
... 5 Combining CHO and protein and in conjunction with resistance training has been shown to stimulate improvements in strength and body composition when compared with control or placebo groups. 6 Previous nutrient timing research has provided information primarily about untrained populations with relatively few incorporating well trained subjects 13,14 and to the authors knowledge no studies have been conducted employing a block periodization training model. Block periodization and appropriate programming has been shown to be efficacious and efficient for the increases in performance compared to other programs, particularly among athletic populations. ...
... The subjects in this study had a high relative strength to body mass ratio before the training protocol which may explain the equivocal strength changes found in both groups from pre to post training. In two studies incorporating trained athletes by 13,14 the investigators report greater changes in 1RM strength for upper and lower body in trained athletes consuming a protein supplement compared to a placebo. These effects could not be replicated during this training protocol which employed a smaller sample size but better trained athletes than the previously mentioned studies. ...
INTRODUCTION: Previous investigations have examined nutrient timing with untrained subject and less is known about effects in trained subjects. OBJECTIVES: The purpose of this study was to examine the effects of a carbohydrate and protein supplement (CHO+PROT) on performance measures in trained weightlifters. METHODS: 10 trained weightlifters (30.8±5.1 years, 177.4 ±4.0 cm, 94.3 ± 12.4 kg, training age = 5.3 ± 2.9 years) completed a 12 week training program utilizing block periodization. Using a double blind placebo design, jump height, scaled peak power measured in vertical jumps and peak force and rate of force development measured in isometric mid-thigh pulls were compared between groups using a series of 2x4 (group x time) repeated measures ANOVA’s. RESULTS: No significant differences (p > 0.05) were observed between treatment and placebo groups in respect to measures of jump height and peak power with weighted and unweighted jumps. Likewise, no statistical differences (p > 0.05) were observed for peak force or rate of force development with isometric mid-thigh pulls. CONCLUSION: These findings indicate that a CHO+PROT supplement provided no additional performance benefits compared to a placebo within a 12 week block periodization protocol in trained weightlifters.
... ,94 Changes in strength data resulting from the additional protein intervention were extracted from 50 studies testing 2283 subjects for lower-body strength33,36-39,43,44,47-49,52-58,61-65,67-70, 72,74-78,82,84,86,88-92,94,96,100-104 and only three studies with intervention groups without RE.41,99,105 Thirty-four studies tested bench-press strength33,[36][37][38]43,[47][48][49][53][54][55][62][63][64][65]67,68,70,72,74,75,77,78,82,84,[86][87][88]90,91,93,95,96,99 with 1049 subjects. The duration of the studies was, on average, 12 weeks for both bench-press and lower body strength. ...
Objectives
This systematic review, meta-analysis, and meta-regression aimed to determine if increasing daily protein ingestion contributes to gaining lean mass (LM), muscle strength, and physical/functional test performance in healthy persons.
Methods
The present review was registered on PROSPERO - CRD42020159001. A systematic search in Medline, Embase, CINAHL, and Web of Sciences databases was undertaken. Randomized controlled trials (RCT) including healthy and non-obese adult participants increasing daily protein intake were selected. Subgroup analysis, splitting the studies by participation in resistance exercise training (RE), age (< 65 or ≥ 65 y), and daily protein ingestion were also performed.
Results
74 RCT fit our inclusion criteria. The age range of the participants was 19 to 85 y, and study protocols in the trials lasted from 6 to 108 wks (76% of the studies between 8 and 12 wks). In ∼80% of the studies, baseline protein ingestion was at least 1.2 g of protein/kg/d. Increasing daily protein ingestion may lead to small gains in LM in subjects enrolled in RE (SMD [standardized mean difference] = 0.22, CI95% [95% confidence interval] 0.14:0.30, P < 0.01, 62 studies, moderate level of evidence). Also, ≥ 65 y subjects ingesting 1.2–1.59 g of protein/kg/d and younger subjects (< 65 y) increasing their ingestion to ≥ 1.6 g of protein/kg/d during RE showed a higher LM gain. Lower-body strength gain was slightly higher at ≥ 1.6 g of protein/kg/d during RE (SMD = 0.40, CI95% 0.09:0.35, P < 0.01, 19 studies, low level of evidence). Bench press strength was slightly increased by ingesting more protein in < 65 y subjects during RE (SMD = 0.18, CI95% 0.03:0.33, P = 0.01, 32 studies, low level of evidence). Effects on handgrip strength are unclear and only marginal for performance in physical function tests.
Conclusions
The number of studies increasing daily protein ingestion alone was too low (n = 6) to conduct a meta-analysis. The current evidence shows that increasing protein ingestion by consuming supplements or food, resulted in small additional gain in LM, and lower body muscle strength in healthy adults enrolled in RE. Effects on bench press strength and performance in physical function tests are minimal. The effect on handgrip strength was unclear.
Funding Sources
This research received a grant from the International Life Science Institute (Europe) and CNPq.
... This could point to the timing of protein intake having no major role immediately post-exercise, at least as judged by the MPS rate measured after acute exercise. Some (37,156) but not all (63) training studies have reported greater resistance training-induced increases in lean mass when protein intake occurred in close proximity www.annualreviews.org • Dietary Fuels in Athletic Performance 10.17 Review in Advance first posted on May 28, 2019. ...
Focusing on daily nutrition is important for athletes to perform and adapt
optimally to exercise training. The major roles of an athlete’s daily diet
are to supply the substrates needed to cover the energy demands for exercise,
to ensure quick recovery between exercise bouts, to optimize adaptations
to exercise training, and to stay healthy. The major energy substrates
for exercising skeletal muscles are carbohydrate and fat stores. Optimizing
the timing and type of energy intake and the amount of dietary macronutrients
is essential to ensure peak training and competition performance, and
these strategies play important roles in modulating skeletal muscle adaptations
to endurance and resistance training. In this review, recent advances in
nutritional strategies designed to optimize exercise-induced adaptations in
skeletal muscle are discussed, with an emphasis on mechanistic approaches,
by describing the physiological mechanisms that provide the basis for different
nutrition regimens.
... Similarly, distributing protein more evenly throughout the day, avoiding large single intakes and extended periods of time without consumed protein, has been shown to enable greater MPS and results in lower body fat percentage [13][14][15]18]. Studies also suggest that male athletes who consume large amounts of protein may not receive the same benefits from increasing protein frequency [19,20]. The American College of Sports Medicine, The Academy of Nutrition and Dietetics, and the Dietitians of Canada's most recent position stand recommends protein intake of 0.3 g/kg body weight immediately after exercise, as well as 0.3 g/kg body weight every 3-5 hours [6]. ...
... A similar conclusion has been reached in other inves- tigations. 33,34 Hoffman et al (2009) observed no difference in the increase in strength after 10-week resistance training in young trained men who had a protein supplement before and after each training session compared with subjects who had a protein supplement in the morning and evening. In recent years, the focus has moved from timing of protein ingestion immediately after exercise to ingestion of protein meals regularly during the day(s) after exercise to support muscle growth. ...
... Protein ingestion has the ability to maximize the acute MPS response following RE though it is ultimately the sum of frequent episodic bouts of heightened anabolism resulting from chronic resistance training (RT) that are fundamental for the augmentation of lean mass. Several studies have examined the influence of chronic protein supplementation on changes in body composition and performance ( Kerksick et al. 2006;Willoughby et al. 2007;Hoffman et al. 2009;Josse et al. 2011) and have shown that protein ingestion enhances RT-induced increases in LBM and strength. Protein quality, as mentioned previously, is crucial to maximize gains in skeletal muscle mass when combined with a potent anabolic stimulus such as RE. ...
... Therefore, the studies afford no reasonable assessment of whether timing of protein intake around exercise is bene- ficial because higher total daily protein intake is a con- founding factor. Only 3 studies in the meta-analysis would be applicable to the question of protein timing [2][3][4]. This is because the studies compared protein supplement in- take in and around workouts to supplement intake some time before and after. ...
This article comments on the study by Schoenfeld, et al. entitled “The effect of protein timing on muscle strength and hypertrophy: a meta-analysis” and discusses how the methodology led to inconclusive results.
... General physical activity (203,204), and RET (127,128,205) in particular, improves efficiency of protein turnover, so theoretically those who become more trained actually would not need more protein; yet, several still posit that RE-trained participants benefit the most. Even so, some have suggested that because trained individuals display a more transient MPS response, protein timing may be important; however, the 2 studies that investigated this hypothesis yielded equivocal results (206,207). Although RE-trained individuals are unlikely to benefit from protein/AA supplementation, unless through a placebo effect, it is interesting to speculate that previously well trained individuals who restart an intensive program after a period of detraining may have enhanced sensitizing to protein/ AA nutrition. ...
The goal of this critical review is to comprehensively assess the evidence for the molecular, physiologic, and phenotypic skeletal muscle responses to resistance exercise (RE) combined with the nutritional intervention of protein and/or amino acid (AA) ingestion in young adults. We gathered the literature regarding the translational response in human skeletal muscle to acute exposure to RE and protein/AA supplements and the literature describing the phenotypic skeletal muscle adaptation to RE and nutritional interventions. Supplementation of protein/AAs with RE exhibited clear protein dose-dependent effects on translational regulation (protein synthesis) through mammalian target of rapamycin complex 1 (mTORC1) signaling, which was most apparent through increases in p70 ribosomal protein S6 kinase 1 (S6K1) phosphorylation, compared with postexercise recovery in the fasted or carbohydrate-fed state. These acute findings were critically tested via long-term exposure to RE training (RET) and protein/AA supplementation, and it was determined that a diminishing protein/AA supplement effect occurs over a prolonged exposure stimulus after exercise training. Furthermore, we found that protein/AA supplements, combined with RET, produced a positive, albeit minor, effect on the promotion of lean mass growth (when assessed in >20 participants/treatment); a negligible effect on muscle mass; and a negligible to no additional effect on strength. A potential concern we discovered was that the majority of the exercise training studies were underpowered in their ability to discern effects of protein/AA supplementation. Regardless, even when using optimal methodology and large sample sizes, it is clear that the effect size for protein/AA supplementation is low and likely limited to a subset of individuals because the individual variability is high. With regard to nutritional intakes, total protein intake per day, rather than protein timing or quality, appears to be more of a factor on this effect during long-term exercise interventions. There were no differences in strength or mass/muscle mass on RET outcomes between protein types when a leucine threshold (>2 g/dose) was reached. Future research with larger sample sizes and more homogeneity in design is necessary to understand the underlying adaptations and to better evaluate the individual variability in the muscle-adaptive response to protein/AA supplementation during RET.
... However, in a similar study in which groups consumed their protein supplement (whey and casein) in the morning/evening or before/ after workout, no difference in terms of strength gains after a 10-week resistance training programme were observed. However, the authors of the second study noted that the caloric intake (∼29 kcal/kg/day) of their subjects, regardless of training group, were below the recommended values for active individuals (Hoffman et al., 2009). ...
IntroductionProtein feeding and resistance exercisePractical considerationsConclusions and remaining questionsReferences
... Peak power output was measured for each jump (VJ) with a Tendo™ Power Output Unit (Tendo Sports Machines, Trencin, Slovak Republic). According to Hoffman, Ratamess, Kang, Rashti, Faigenbaum and Tranchina (2009), the test-retest reliability of the Tendo unit is r0.90. ...
In the prediction of lower body explosive power (LBEP), very few researchers have investigated
the possibility of making use of anthropometric variables to compile prediction models.
Therefore the purpose of this study was to develop a LBEP prediction model from several
anthropometric measurements for a cohort of adolescent boys and girls living in the Tlokwe local
municipality of the Dr Kenneth Kaunda district in the North West Province, South Africa. This
was a cross-sectional experimental design on a purposeively selected cohort of 214 adolescents
(15.82±0.68 years) consisting of 88 boys and 126 girls who were part of the Physical Activity
and Health Longitudinal Study (PAHLS). Data were obtained by means of skinfold (SF) and
LBEP measurements as well as the calculation of maturity age. The results of the forward
stepwise regression analysis shows that stature (57%), muscle mass percentage (10%) and
maturation age (3%) were the anthropometric variables that served as significant (p<0.001)
predictors of LBEP. In view of the fact that the majority of coaches and teachers in South Africa
have very limited means to directly measure anthropometric variables and LBEP in adolescents,
the use of adolescents’ stature, muscle mass and maturity age may possibly serve as an accurate
alternative to predict adolescents’ LBEP.
... In support, several studies reported that ingesting protein-based supplements before and/or after resistance training resulted in significantly greater gains in strength and muscle hypertrophy over placebo controls in both trained and untrained individuals (Coburn et al. 2006; Hulmi et al. 2010; Walker et al. 2010; Willoughby et al. 2007). However, others have observed no added benefit of amino acid or protein supplementation on muscle mass and/or strength following 6–10 weeks of resistance training in both trained and untrained individuals (Antonio et al. 2000; Hoffman et al. 2009). The conflicting results may be the result of differing methods of strength and muscle morphological assessment , participant training status, training program, and/or the amount or type of protein used. ...
Short-term resistance training has consistently demonstrated gains in muscular strength, but not hypertrophy. Post-resistance training protein ingestion is posited to augment the acute anabolic stimulus, thus potentially accelerating changes in muscle size and strength. The purpose of this investigation was to examine the effects of 4 weeks of resistance training with protein supplementation on strength and muscle morphology changes in untrained men. Participants (mean ± SD; N = 18; age, 22.0 ± 2.5 years; body mass index, 25.1 ± 5.4 kg·m(-2)) were randomly assigned to a resistance training + protein group (n = 9; whey (17 g) + colostrum (3 g) + leucine (2 g)) or a resistance training + placebo group (n = 9). One-repetition maximum (1RM) strength in the leg press (LP) and leg extension (LE) exercises, maximal isometric knee extensor strength (MVIC), and muscle morphology (thickness (MT), cross-sectional area (CSA), pennation angle) of the dominant rectus femoris (RF) and vastus lateralis (VL) was assessed before and after training. Participants performed LP and LE exercises (3 × 8-10; at 80% 1RM) 3 days/week for 4 weeks. Data were analyzed using 2-way ANOVA with repeated measures. Four weeks of resistance training resulted in significant increases in LP (p < 0.001), LE (p < 0.001), MVIC (p < 0.001), RF MT (p < 0.001), RF CSA (p < 0.001), VL MT (p < 0.001), and VL CSA (p < 0.001). No between-group differences were observed. Although nutrition can significantly affect training adaptations, these results suggest that short-term resistance training augments muscle strength and size in previously untrained men with no additive benefit from postexercise protein supplementation.
... The influence of timing of protein intake to stimulate resistance exercise-induced muscle anabolism has been studied extensively in recent years. Although not all studies agree [108,109], a number of investigations suggest that the anabolic effect of protein intake (with or without carbohydrate stimulates) is increased when taken before or immediately after exercise than at other times of the day [103,110,111]. During and within the first 2 hours following exercise, the physiological state of the body appears to be more suitable for rapid protein resynthesis than in a delayed condition (3 hours), possibly because of increases in muscle blood flow, insulin sensitivity and delivery of amino acids to muscle [112]. ...
• Most previous studies on the effect of age on sprint performance are based on cross-sectional design that is limited in its ability in determining causality between performance/physiological changes and ageing. To define the true effect of ageing on sprint performance and its determinants, there is need for more longitudinal studies where athletes are followed for several years.
• Perhaps the most fundamental impact of ageing on physical performance is the progressive loss of muscle fibres, especially fast type II fibres. Although this change is commonly thought to be inevitable, recent studies have suggested that the muscle fibre loss can be prevented or slowed by regular endurance exercise. This issue clearly warrants further exploration in masters athletes from various sports.
• Studies should be conducted to evaluate muscle-tendon behaviour and elastic energy utilisation in ageing athletes. Due to exercise-type and intensity specificity, the muscle-tendon interaction should be measured in vivo during the contact phase of fast running. In addition, because older sprinters show variability in foot strike pattern (forefoot, midfoot, rearfoot), we need also to know how the landing strategy affect the spring-like bouncing mechanism.
• To date, the studies on the effect of ageing on anaerobic metabolic characteristics such as muscle enzyme activities and ATP, PCr and lactate concentrations have focused on non-athletes. However, well-trained masters sprinters may have very different metabolic capabilities than normal age-matched individuals. More research on muscle metabolism and its role in age-related differences in sprint performance in masters sprint athletes is needed.
• Decreased ability to tolerate heavy training may be a key factor for age-related performance losses. However, the physiological bases of diminishing trainability with age is still unclear. More studies on the possible effects of anabolic hormonal and nutrition factors on trainability in masters athletes should be undertaken.
• Although the values for various performance and musculoskeletal properties in masters sprint athletes are maintained far above the age norms, the available evidence for potential training-related risks are still very limited. New information about the benefits and risks of demanding strength-, run- and jump-based exercises is needed not only to counsel the masters athletes themselves but also to develop modified training programs for non-athletes in whom the improvement of rapid force and musculoskeletal characteristics with age has good potential to enhance functional well-being.
• With very few exceptions, most of the studies on the effects of ageing on sprint performance have used male participants. More research is needed to learn how the physiological factors related to sprint performance are affected by gender.
... In the present study, the trained group showed less muscle protein accumulation than in the untrained group even though the former showed a higher effect of taking protein and carbohydrate immediately after resistance exercise, indicating that their skeletal muscle mass hardly increased compared with that observed in the 7-week resistance training period in our previous study. In a separate study of trained men conducted by Hoffman et al., skeletal muscle mass did not increase with protein supplementation before or after 10 weeks of resistance training [22]. However, in a study of untrained men, Bird et al. reported an increase in skeletal muscle mass after taking essential amino acids and carbohydrate over 12 weeks of resistance training [8]. ...
Background
Resistance exercise alters the post-exercise response of anabolic and catabolic hormones. A previous study indicated that the turnover of muscle protein in trained individuals is reduced due to alterations in endocrine factors caused by resistance training, and that muscle protein accumulation varies between trained and untrained individuals due to differences in the timing of protein and carbohydrate intake. We investigated the effect of the timing of protein and carbohydrate intake after resistance exercise on nitrogen balance in trained and untrained young men.
Methods
Subjects were 10 trained healthy men (mean age, 23 ± 4 years; height, 173.8 ± 3.1 cm; weight, 72.3 ± 4.3 kg) and 10 untrained healthy men (mean age, 23 ± 1 years; height, 171.8 ± 5.0 cm; weight, 64.5 ± 5.0 kg). All subjects performed four sets of 8 to 10 repetitions of a resistance exercise (comprising bench press, shoulder press, triceps pushdown, leg extension, leg press, leg curl, lat pulldown, rowing, and biceps curl) at 80% one-repetition maximum. After each resistance exercise session, subjects were randomly divided into two groups with respect to intake of protein (0.3 g/kg body weight) and carbohydrate (0.8 g/kg body weight) immediately after (P0) or 6 h (P6) after the session. All subjects were on an experimental diet that met their individual total energy requirement. We assessed whole-body protein metabolism by measuring nitrogen balance at P0 and P6 on the last 3 days of exercise training.
Results
The nitrogen balance was significantly lower in the trained men than in the untrained men at both P0 (P <0.05) and P6 (P <0.01). The nitrogen balance in trained men was significantly higher at P0 than at P6 (P <0.01), whereas that in the untrained men was not significantly different between the two periods.
Conclusion
The timing of protein and carbohydrate intake after resistance exercise influences nitrogen balance differently in trained and untrained young men.
... Burk et al. [82], found that a time-divided regimen (two 35 g protein doses consumed at far-off points in the morning and evening away from the afternoon training bout) caused slightly better gains in squat strength and fat-free mass than the time-focused regimen, where the protein supplement doses were consumed in the morning, and then again immediately prior to the resistance training bout. Hoffman et al. [83] found no significant differences in strength gains or body composition when comparing an immediate pre-and post-exercise supplement ingestion (each dose provided 42 g protein) with the supplement ingested distantly separate from each side of the training bout. This lack of effect was attributed to the subjects' sufficient daily protein consumption combined with their advanced lifting status. ...
The popularity of natural bodybuilding is increasing; however, evidence-based recommendations for it are lacking. This paper reviewed the scientific literature relevant to competition preparation on nutrition and supplementation, resulting in the following recommendations. Caloric intake should be set at a level that results in bodyweight losses of approximately 0.5 to 1%/wk to maximize muscle retention. Within this caloric intake, most but not all bodybuilders will respond best to consuming 2.3-3.1 g/kg of lean body mass per day of protein, 15-30% of calories from fat, and the reminder of calories from carbohydrate. Eating three to six meals per day with a meal containing 0.4-0.5 g/kg bodyweight of protein prior and subsequent to resistance training likely maximizes any theoretical benefits of nutrient timing and frequency. However, alterations in nutrient timing and frequency appear to have little effect on fat loss or lean mass retention. Among popular supplements, creatine monohydrate, caffeine and beta-alanine appear to have beneficial effects relevant to contest preparation, however others do not or warrant further study. The practice of dehydration and electrolyte manipulation in the final days and hours prior to competition can be dangerous, and may not improve appearance. Increasing carbohydrate intake at the end of preparation has a theoretical rationale to improve appearance, however it is understudied. Thus, if carbohydrate loading is pursued it should be practiced prior to competition and its benefit assessed individually. Finally, competitors should be aware of the increased risk of developing eating and body image disorders in aesthetic sport and therefore should have access to the appropriate mental health professionals.
... Despite the apparent biological plausibility of the strategy, the effectiveness of protein timing in chronic training studies has been decidedly mixed. While some studies have shown that consumption of protein in the peri-workout period promotes increases in muscle strength and/or hypertrophy [16-19], others have not [20-22]. In a review of literature, Aragon and Schoenfeld [23] concluded that there is a lack of evidence to support a narrow “anabolic window of opportunity” whereby protein need to be consumed in immediate proximity to the exercise bout to maximize muscular adaptations. ...
Protein timing is a popular dietary strategy designed to optimize the adaptive response to exercise. The strategy involves consuming protein in and around a training session in an effort to facilitate muscular repair and remodeling, and thereby enhance post-exercise strength- and hypertrophy-related adaptations. Despite the apparent biological plausibility of the strategy, however, the effectiveness of protein timing in chronic training studies has been decidedly mixed. The purpose of this paper therefore was to conduct a multi-level meta-regression of randomized controlled trials to determine whether protein timing is a viable strategy for enhancing post-exercise muscular adaptations. The strength analysis comprised 478 subjects and 96 ESs, nested within 41 treatment or control groups and 20 studies. The hypertrophy analysis comprised 525 subjects and 132 ESs, nested with 47 treatment or control groups and 23 studies. A simple pooled analysis of protein timing without controlling for covariates showed a small to moderate effect on muscle hypertrophy with no significant effect found on muscle strength. In the full meta-regression model controlling for all covariates, however, no significant differences were found between treatment and control for strength or hypertrophy. The reduced model was not significantly different from the full model for either strength or hypertrophy. With respect to hypertrophy, total protein intake was the strongest predictor of ES magnitude. These results refute the commonly held belief that the timing of protein intake in and around a training session is critical to muscular adaptations and indicate that consuming adequate protein in combination with resistance exercise is the key factor for maximizing muscle protein accretion.
... Positive correlations were found between one of the indices of muscle power, the vertical-jump height, and the daily energy and protein intakes. Protein plays an important role in the recovery of muscle damage arising from training, as well as from muscle fiber hypertrophy,23 and consequently contributes to an improvement in physical performance.24,25 Our results support the suggestion that protein intake may be correlated with physical function. ...
The objectives of this study were to reveal the proportion of Shorinji Kempo athletes who had suffered fractures related to sports activities, and to evaluate bone mass, bone turnover, nutritional status, and physical function in these athletes. A medical examination was carried out for 16 Shorinji Kempo collegiate athletes. Seven athletes (43.8%) had experienced a sports-related traumatic fracture during Shorinji Kempo practice. Four athletes (25.0%) had a lower speed of sound (% young adult mean < 100%), and five athletes (31.3%) had higher levels of urinary cross-linked N-terminal telopeptides of type 1 collagen (a bone turnover marker) than the age-adjusted standard values. All the athletes had a lower daily calcium intake than the adequate intake, 12 (75.0%) had a lower daily vitamin D intake, and 15 (93.8%) had a lower daily vitamin K intake. Significant positive correlations were found between the vertical jump height, and the daily energy, and protein intakes. Results suggest that fractures are a common injury in Shorinji Kempo athletes, and that some Shorinji Kempo athletes need to improve their bone mass, bone metabolism, and nutritional status in order to strengthen bone and improve physical function.
... Por ejemplo, las necesidades proteicas para dos deportistas de fuerza de 90 kg de peso que difi eran en sus porcentajes de masa muscular no deberían ser iguales, debido a que el individuo con un mayor porcentaje de masa muscular requerirá supuestamente de un mayor aporte de proteínas para mantener el estado anabólico que el de menor tejido muscular. Pese a que no se han encontrado muchos estudios que contemplen este aspecto, en dos estudios se concluye que la ingesta óptima de proteínas para alcanzar el máximo desarrollo muscular se sitúa en 3,3-3,4 g de proteínas por kg de masa muscular 3,54 . ...
One of the most important effects of strength training is muscular hypertrophy. Athletes should optimize their nutritional management in order to compensate their own genetic limitations. The aim of this review is to analyze the scientific evidence concerning protein intake as a tool to achieve muscle hypertrophy. Depending on the expenditure and energy intake of athlete, a daily protein ranging between 10–15% of total dietary intake is needed. However in sports diets, it is preferable to estimate the amount of protein needed per kilogram of body weight in each individual. In this regard athletes should ingest an amount between 1.2 g and 1.8 g of proteins/kg of body mass/day to maintain their lean mass. In order to increase muscle mass (0.5 kg/week), athletes should take between 1.6 g and 1.8 g of protein/kg/day with an increase of 400–500 kcal in their daily diet. These needs will depend on the sport, muscular catabolic status, the athlete's lean mass and glycogen stores. Protein needs will increase if muscle and liver glycogen stores are empty. Excess of protein intake (more than 2 g/kg/day), with full glycogen stores, does not benefit the athlete and could cause an increase in circulating ketones and urea, thereby producing an early dehydration.
... Indeed, others have found that timed protein supplementation immediately before and after exercise does not further enhance muscle mass or strength in healthy elderly men who habitually consume adequate amounts of dietary protein [40]. Also, timed protein-supplement ingestion in resistance-trained athletes during a 10-week training program does not further enhance strength, power, or body-composition changes [41]. ...
Chronic supplementation with creatine monohydrate has been shown to promote increases in total intramuscular creatine, phosphocreatine, skeletal muscle mass, lean body mass and muscle fiber size. Furthermore, there is robust evidence that muscular strength and power will also increase after supplementing with creatine. However, it is not known if the timing of creatine supplementation will affect the adaptive response to exercise. Thus, the purpose of this investigation was to determine the difference between pre versus post exercise supplementation of creatine on measures of body composition and strength.
Nineteen healthy recreational male bodybuilders (mean +/- SD; age: 23.1 +/- 2.9; height: 166.0 +/- 23.2 cm; weight: 80.18 +/- 10.43 kg) participated in this study. Subjects were randomly assigned to one of the following groups: PRE-SUPP or POST-SUPP workout supplementation of creatine (5 grams). The PRE-SUPP group consumed 5 grams of creatine immediately before exercise. On the other hand, the POST-SUPP group consumed 5 grams immediately after exercise. Subjects trained on average five days per week for four weeks. Subjects consumed the supplement on the two non-training days at their convenience. Subjects performed a periodized, split-routine, bodybuilding workout five days per week (Chest-shoulders-triceps; Back-biceps, Legs, etc.). Body composition (Bod Pod(R)) and 1-RM bench press (BP) were determined. Diet logs were collected and analyzed (one random day per week; four total days analyzed).
2x2 ANOVA results - There was a significant time effect for fat-free mass (FFM) (F = 19.9; p = 0.001) and BP (F = 18.9; p < 0.001), however, fat mass (FM) and body weight did not reach significance. While there were trends, no significant interactions were found. However, using magnitude-based inference, supplementation with creatine post workout is possibly more beneficial in comparison to pre workout supplementation with regards to FFM, FM and 1-RM BP. The mean change in the PRE-SUPP and POST-SUPP groups for body weight (BW kg), FFM (kg), FM (kg) and 1-RM bench press (kg) were as follows, respectively: Mean +/- SD; BW: 0.4 +/- 2.2 vs 0.8 +/- 0.9; FFM: 0.9 +/- 1.8 vs 2.0 +/- 1.2; FM: -0.1 +/- 2.0 vs -1.2 +/- 1.6; Bench Press 1-RM: 6.6 +/- 8.2 vs 7.6 +/- 6.1.Qualitative inference represents the likelihood that the true value will have the observed magnitude. Furthermore, there were no differences in caloric or macronutrient intake between the groups.
Creatine supplementation plus resistance exercise increases fat-free mass and strength. Based on the magnitude inferences it appears that consuming creatine immediately post-workout is superior to pre-workout vis a vis body composition and strength.
... The temporal pattern of protein/amino acid intake relative to exercise may also impact the amount of lean mass accrual following more long-term resistance exercise training. Some ( Esmarck et al. 2001;Cribb and Hayes 2006;Burk et al. 2009) but not all studies (Hoffman et al. 2009) have reported greater lean mass accrual when supplement timing occurs in close temporal proximity to resistance exercise (i.e., immediately before and/or after exercise) as compared to the same supplement provided at times temporally dissociated from the exercise stimulus (i.e., in the morning several hours before exercise). For example, delaying protein intake by 2 h after resistance exercise in a group of elderly men ablated lean mass gains and greatly diminished strength gains when compared to a group of elderly men who ingested protein within *5 min after resistance exercise (Esmarck et al. 2001). ...
Amino acids are major nutrient regulators of muscle protein turnover. After protein ingestion, hyperaminoacidemia stimulates increased rates of skeletal muscle protein synthesis, suppresses muscle protein breakdown, and promotes net muscle protein accretion for several hours. These acute observations form the basis for strategized protein intake to promote lean mass accretion, or prevent lean mass loss over the long term. However, factors such as protein dose, protein source, and timing of intake are important in mediating the anabolic effects of amino acids on skeletal muscle and must be considered within the context of evaluating the reported efficacy of long-term studies investigating protein supplementation as part of a dietary strategy to promote lean mass accretion and/or prevent lean mass loss. Current research suggests that dietary protein supplementation can augment resistance exercise-mediated gains in skeletal muscle mass and strength and can preserve skeletal muscle mass during periods of diet-induced energy restriction. Perhaps less appreciated, protein supplementation can augment resistance training-mediated gains in skeletal muscle mass even in individuals habitually consuming 'adequate' (i.e., >0.8 g kg(-1) day(-1)) protein. Additionally, overfeeding energy with moderate to high-protein intake (15-25 % protein or 1.8-3.0 g kg(-1) day(-1)) is associated with lean, but not fat mass accretion, when compared to overfeeding energy with low protein intake (5 % protein or ~0.68 g kg(-1) day(-1)). Amino acids represent primary nutrient regulators of skeletal muscle anabolism, capable of enhancing lean mass accretion with resistance exercise and attenuating the loss of lean mass during periods of energy deficit, although factors such as protein dose, protein source, and timing of intake are likely important in mediating these effects.
We performed a systematic review and meta-analysis to study all published clinical trial interventions, determined the magnitude of whole-body hypertrophy in humans (healthy males) and observed the individual responsibility of each variable in muscle growth after resistance training (RT). Searches were conducted in PubMed, Web of Science and the Cochrane Library from database inception until 10 May 2018 for original articles assessing the effects of RT on muscle size after interventions of more than 2 weeks of duration. Specifically, we obtain the variables fat-free mass (FMM), lean muscle mass (LMM) and skeletal muscle mass (SMM). The effects on outcomes were expressed as mean differences (MD) and a random-effects meta-analysis and meta-regressions determined covariates (age, weight, height, durations in weeks…) to explore the moderate effect related to the participants and characteristics of training. One hundred and eleven studies (158 groups, 1927 participants) reported on the effects of RT for muscle mass. RT significantly increased muscle mass (FFM+LMM+SMM; Δ1.53 kg; 95% CI [1.30, 1.76], p < 0.001; I2 = 0%, p = 1.00). Considering the overall effects of the meta-regression, and taking into account the participants' characteristics, none of the studied covariates explained any effect on changes in muscle mass. Regarding the training characteristics, the only significant variable that explained the variance of the hypertrophy was the sets per workout, showing a significant negative interaction (MD; estimate: 1.85, 95% CI [1.45, 2.25], p < 0.001; moderator: -0.03 95% CI [−0.05, −0.001] p = 0.04). In conclusion, RT has a significant effect on the improvement of hypertrophy (~1.5 kg). The excessive sets per workout affects negatively the muscle mass gain.
The age-related progressive loss of skeletal muscle mass and function, termed sarcope-nia, is associated with physical disabilities, the loss of independence, and an increased risk of developing chronic metabolic disease. Skeletal muscle satellite cells play a key role in the maintenance, regeneration and growth of muscle tissue. Therefore, age-related changes in satellite cell content and/or function have been suggested to play an important role in the etiology of sarcopenia. In this thesis, we examined the potential regulatory role of satellite cell pool size and function in relation to both acute and more prolonged muscle atrophy and hypertrophy signals in humans.
In Chapter 2 of this thesis we determined muscle fiber characteristics in skeletal muscle tissue in a large group of people with ages ranging over the entire life span. We ob-served a decline in type II muscle fiber size with an increasing age. The type II muscle fiber atrophy with aging is accompanied by a muscle fiber type-specific decline in satel-lite cell content. However, the age-related reduction in type II muscle fiber size and satellite cell content can be completely reversed following prolonged resistance type exercise training in healthy elderly men. Obviously, the reduced level of physical activity may play an important role in the development of type II muscle fiber atrophy and asso-ciated changes in satellite cell content with aging. In Chapter 3 we studied the impact of reducing the level of physical activity on muscle fiber size and satellite cell content. Young adults were subjected to 2 weeks of one-legged knee immobilization by means of a full leg cast. Two weeks of single legged knee immobilization resulted in a considerable decline in both type I and type II muscle fiber size but without any changes in satellite and/or myonuclear content. Subsequently, the work in this chapter suggests that a de-cline in satellite cell content is not a mechanistic prerequisite for disuse induced muscle atrophy.
Apart from satellite cell content, impairments in the satellite cell activation response to anabolic stimuli may also contribute to the development of sarcopenia. Chapter 4 and 5 introduce novel immunohistological techniques that were applied to investigate changes in satellite cell activation status in human skeletal muscle biopsy samples. Skeletal mus-cle satellite cell activation status is shown to change within 9 hours of recovery after exercise. In addition, we report that changes in satellite cell content and/or activation status occur in a muscle fiber type-specific manner during the first 24 h after a single bout of exercise. These two studies emphasize the importance of analyzing changes in satellite cell activation, proliferation and/or differentiation in a muscle fiber type-specific manner in response to various anabolic stimuli in both health and disease. Sub-sequently, in Chapter 6 we determined the time-dependent changes in type I and type II muscle fiber satellite cell content and activation status in both healthy young and elderly men in response to a single bout of resistance type exercise. In this study we demon-strate that during post-exercise recovery the increase in satellite cell content is delayed with aging and is accompanied by a blunted satellite cell activation response. This atten-uated response may be instrumental in the reduced capacity of senescent muscle to respond to prolonged resistance type exercise training.
In a further attempt to unravel the different factors involved in the satellite cell re-sponse to an exercise stimulus, we also looked at the potential role of nutrition. It has been well-documented that during post-exercise recovery, dietary protein intake is essential to support the increase in myofibrillar muscle protein synthesis, thereby allow-ing net muscle protein accretion. On the other hand, for more long-term muscle adapta-tion, satellite cells are required to provide additional myonuclei to allow muscle fiber hypertrophy. In Chapter 7, we investigated whether dietary protein intake is also pre-requisite to allow a proper satellite response during recovery from a single bout of re-sistance type exercise. Here we show that an acute reduction in protein intake does not affect the increase in satellite cell content but does change the timeline of myostatin expression during 72 h of post-exercise recovery. We speculate that the altered myo-statin response may represent a compensatory response to allow muscle reconditioning to occur when dietary protein becomes available.
Moving forward in the line of a combined exercise and nutritional approach, in Chapter 8 we assessed whether dietary protein ingestion prior to sleep would have a surplus benefit on the increase in skeletal muscle mass and strength following 12 weeks of re-sistance type exercise training. In a previous study from our lab we have shown that protein ingestion prior to sleep increases muscle protein synthesis rates during post-exercise overnight recovery. However, whether these acute changes in muscle protein synthesis also translate to skeletal muscle adaptation to more prolonged resistance type exercise training remained to be established. In agreement with earlier work, progres-sive resistance type exercise training resulted in an increase in skeletal muscle mass and strength in both the placebo as well as the protein supplemented group of healthy young men. However, the increase in skeletal muscle mass and strength was significantly greater in the protein supplemented group. We concluded that protein ingestion prior to sleep represents an effective dietary strategy to augment skeletal muscle mass and strength gains during prolonged resistance type exercise training in healthy young males.
On the muscle fiber level, the gains in muscle mass and strength in response to the 12 weeks training program were accompanied by both type I and type II muscle fiber hy-pertrophy. It is generally believed that muscle fiber hypertrophy is initially supported by an increase in myonuclear domain size. However, the existing myonuclei can only sup-port the underlying increase in transcriptional activity to a certain extent. Subsequently, the incorporation of new, satellite cell derived myonuclei may be required to allow more extensive long-term muscle fiber growth, as was also shown in Chapter 2. In Chap-ter 9, we specifically examined whether an initial (temporary) increase in myonuclear domain size represents a crucial driving force for subsequent myonuclear accretion in response to prolonged resistance type exercise training. Therefore, the change in mus-cle fiber size, myonuclear domain size, myonuclear and satellite cell content were as-sessed at different time-points throughout 12 weeks of resistance type exercise train-ing. We show that muscle fiber hypertrophy is accompanied by a time-dependent in-crease in myonuclear and satellite cell content in response to 12 weeks of resistance type exercise training in young men. However, the exercise training induced muscle fiber hypertrophy is not accompanied by any temporary or permanent increase in myo-nuclear domain size. As such, changes in myonuclear domain size do not seem to be required to elicit myonuclear accretion and support subsequent muscle hypertrophy in healthy young males.
The final chapter addresses the implications of the findings presented in this thesis, and identifies a number of key topics that need to be addressed in future research. This thesis shows that skeletal muscle satellite cells represent an important factor in exercise induced muscle fiber hypertrophy. As such, an impairment in satellite cell function dur-ing post-exercise recovery, as observed in healthy elderly men, may be a crucial factor in the development of sarcopenia, and forms a primary target for intervention strategies aimed to counteract sarcopenia and improve muscle mass and function in the elderly.
The purposes of this dissertation were to examine the effect of a protein and carbohydrate recovery beverage versus a placebo on weightlifting performance, its effect on muscle morphological changes and specific muscle protein accretion. The following are major finding from the dissertation: 1) Protein and carbohydrate recovery supplementation does not appear to have influence on performance measure in trained weightlifters. This finding may be associated with the short-term nature of this study and the trained population used. 2) Compared with placebo, a protein and carbohydrate beverage provided greater benefits on cross sectional area of type I and type II muscle fibers. Additionally, the block periodization protocol incorporating phase potentiation improved cross sectional area of both groups compared to baseline. 3) Finally, protein and carbohydrate supplementation provided greater benefits on total mTOR and myosin heavy chains 6 & 7. These findings indicate that a protein and carbohydrate beverage provide greater benefits compared with a placebo on cellular signaling, myosin heavy gene expression and muscle fiber increases in trained weightlifters. Improved cross sectional area and increased myosin heavy chains indicate positive adaptations to resistance training combined with supplementation and may indicate improved skeletal muscle qualities necessary for increased power output. The mTOR pathway is the master regulator of cellular growth and increases in total mTOR indicate a greater proclivity for cellular growth and greater activity resulting from resistance training may increase synthesis and accretion of muscle contractile proteins. This dissertation highlighted several benefits of recovery supplementation, however further longitudinal studies utilizing block periodization and well-trained athletes are necessary to fully elucidate benefits for strength and power athletes.
Skeletal muscle is critical for human health. Protein feeding, alongside resistance exercise, is a potent stimulus for muscle protein synthesis (MPS) and is a key factor that regulates skeletal muscle mass (SMM). The main purpose of this narrative review was to evaluate the latest evidence for optimising the amino acid or protein source, dose, timing, pattern and macronutrient coingestion for increasing or preserving SMM in healthy young and healthy older adults. We used a systematic search strategy of PubMed and Web of Science to retrieve all articles related to this review objective. In summary, our findings support the notion that protein guidelines for increasing or preserving SMM are more complex than simply recommending a total daily amount of protein. Instead, multifactorial interactions between protein source, dose, timing, pattern and macronutrient coingestion, alongside exercise, influence the stimulation of MPS, and thus should be considered in the context of protein recommendations for regulating SMM. To conclude, on the basis of currently available scientific literature, protein recommendations for optimising SMM should be tailored to the population or context of interest, with consideration given to age and resting/post resistance exercise conditions.
Few supplement combinations that are marketed to athletes are supported by scientific evidence of their effectiveness. Under the rigor of scientific investigation, we often see that the patented combination fails to provide any greater benefit when compared to an active (generic) ingredient. The focus of this chapter is supplement combinations and dosing strategies that are effective at promoting an acute physiological response that may improve/enhance exercise performance and/or influence chronic adaptations desired from training. In recent years, there has been a particular focus on two nutrition ergogenic aids—creatine monohydrate and protein/amino acids—in combination with specific nutrients in an effort to augment or add to their already established independent ergogenic effects. These combinations and others are discussed in this chapter.
Nutrient timing is a popular strategy used by athletes, coaches, and researchers to maximize performance and the adaptations resulting from exercise training. Ingestion of key nutrients before, during, and after various forms of exercise has been shown to favorably impact a number of factors that go on to effect health, performance, and recovery. Research in this area is rapidly expanding, and findings are changing on an annual basis. This chapter is broken into sections discussing current recommendations and scientific findings concerning the administration of macronutrients, micronutrients, and other non-nutrients before, during, and after both endurance and resistance exercise. Finally, recommendations are put forth regarding when to employ various strategies, as well as whether certain strategies are worthy of consideration. Key points related to protein timing, caffeine timing, meal patterns, and caloric distribution are all covered in this chapter.
Nutritional status has a direct bearing on the level of physical performance, that's why sports nutrition is considered as an integral part of sports medicine. The aim of the study was to evaluate the nutritional status of Indian female athletes. To solve the purpose, a total of purposely selected 100 Indian female athletes aged 20-25 years (mean age 21.87 years ± 2.59) collected from six Indian universities, were considered for the present study. The competition was organized in Guru Nanak Dev University, Amritsar, Punjab, India. An equal number of controls (n=100) were also collected from the same place for comparisons. Six anthropometric characteristics, viz. height, weight, BMI, waist circumference, hip circumference, waist to hip ratio and mid-upper arm circumference were considered in this purpose. A pre-tested semi-structured questionnaire and 24-hours recall method were applied for the assessment of nutritional status of the athletes. Results indicated statistically significant differences (p<.001) in hip circumference and waist to hip ratio between Indian female athletes and controls. So far BMI was concerned, no significant differences were found between Indian athletes and controls, showing majority of individuals fall well within the normal range of BMI. When mean nutrient intake of athletes and controls were compared, significant differences (p<.05 -.001) were found in all the variables studied, except energy, iron and sodium between them. It may be concluded from the present study that nutritional status of Indian female athletes were superior as compared to their control counterparts.
Protein consumption is unquestionably required for skeletal muscle maintenance and growth. However, debate persists over whether or not the timing of ingestion matters. Some argue immediately after exercise is best, whereas others disagree. This article will discuss the importance of timing of postexercise protein ingestion. © National Strength and Conditioning Association.
Introdução:
Atletas de halterofilismo buscam aumentar sua força em relação ao peso corporal utilizando treinamento resistido e a nutrição como ferramentas para melhorar o desempenho. Apesar dos benefícios proporcionados por um adequado planejamento alimentar, muitos atletas utilizam estratégias inadequadas, manifestadas pela piora na composição corporal e no desempenho esportivo.
Objetivo:
Analisar o consumo energético e proteico e o uso de suplementos alimentares de paratletas a fim de avaliar a influência da estratégia dietética no desempenho.
Métodos:
Foram coletados dados pessoais, medidas antropométricas, informações referentes ao comportamento alimentar e da competição de 24 paratletas halterofilistas do sexo masculino.
Resultados:
A quantidade de calorias e as porções de macronutrientes consumidas pela alimentação foram em média 2.235,8 ± 694,92 kcal, 27 ± 11,55% proteínas, 46 ± 8,17% carboidratos e 27 ± 8,57% lipídeos. Dos atletas estudados, 87,5% relataram utilizar suplementos alimentares. Os atletas com maior índice de massa corporal (IMC) apresentaram menor ingestão energética e proteica relativa, maior somatório de dobras cutâneas e desempenho similar a dos demais estudados.
Conclusão:
A estratégia utilizada pelos atletas de maior massa corporal não propiciou melhoria direta no desempenho e influen-ciou negativamente na composição corporal. Este fato deve-se provavelmente à falta de adequação entre dieta e suplementação.
Objective:
it is an innovative study where has been analyzed the diet among gym users with Muscle Dysmorphia (MD) of gyms in the province of Alicante.
Methodology:
it have been analyzed 141 male gymnasts of several gyms of Alicante (urban area of southeastern Spanish) aged between 18-45 years old, who purpose increasing their muscle mass. Were considered BMI (kg/m2) and 24 hour diet. And it has been determined whether or not suffer MD trough Muscle Appearance Satisfaction Scale.
Results:
the sample consisted of 141 men, of whom 45 are MD and 96 are not according to Muscle Appearance Satisfaction. Protein intake was calculated and was greater than 1.5 g/kg/day in patients without MD and greater than 2 g/kg/day in the MD group. Analyzing the other nutrients, results show that the proportion of carbohydrates and fats and their percentages by degree of instauration are within the recommendations except cholesterol which exceeds and the amount of dietary fiber that is slightly lower. In relation to micronutrients are within the recommendations in all cases except iodine which is slightly lower in MD.
Conclusion:
individuals with MD do a balanced energy and adequate carbohydrate and fat diet, however protein intake values exceed the limits proposed according to the scientific evidence for muscle mass development in strength sports.
A number of factors contribute to success in sport, and diet is a key component. An athlete's dietary requirements depend on several aspects, including the sport, the athlete's goals, the environment, and practical issues. The importance of individualized dietary advice has been increasingly recognized, including day-to-day dietary advice and specific advice before, during, and after training and/or competition. Athletes use a range of dietary strategies to improve performance, with maximizing glycogen stores a key strategy for many. Carbohydrate intake during exercise maintains high levels of carbohydrate oxidation, prevents hypoglycemia, and has a positive effect on the central nervous system. Recent research has focused on athletes training with low carbohydrate availability to enhance metabolic adaptations, but whether this leads to an improvement in performance is unclear. The benefits of protein intake throughout the day following exercise are now well recognized. Athletes should aim to maintain adequate levels of hydration, and they should minimize fluid losses during exercise to no more than 2% of their body weight. Supplement use is widespread in athletes, with recent interest in the beneficial effects of nitrate, beta-alanine, and vitamin D on performance. However, an unregulated supplement industry and inadvertent contamination of supplements with banned substances increases the risk of a positive doping result. Although the availability of nutrition information for athletes varies, athletes will benefit from the advice of a registered dietician or nutritionist.
Dividing training objectives into consecutive phases to gain morphological adaptations (hypertrophy phase) and neural adaptations (strength and power phases) is called strength-power periodization (SPP). These phases differ in program variables (volume, intensity, and exercise choice or type) and use stepwise intensity progression and concomitant decreasing volume, converging to peak intensity (peaking phase). Undulating periodization strategies rotate these program variables in a bi-weekly, weekly, or daily fashion. The following review addresses the effects of different short-term periodization models on strength and speed-strength both with subjects of different performance levels and with competitive athletes from different sports who use a particular periodization model during off-season, pre-season, and in-season conditioning. In most periodization studies, it is obvious that the strength endurance sessions are characterized by repetition zones (12–15 repetitions) that induce muscle hypertrophy in persons with a low performance level. Strictly speaking, when examining subjects with a low training level, many periodization studies include mainly hypertrophy sessions interspersed with heavy strength/power sessions. Studies have demonstrated equal or statistically significant higher gains in maximal strength for daily undulating periodization compared with SPP in subjects with a low to moderate performance level. The relatively short intervention period and the lack of concomitant sports conditioning call into question the practical value of these findings for competitive athletes. Possibly owing to differences in mesocycle length, conditioning programs, and program variables, competitive athletes either maintained or improved strength and/or speed-strength performance by integrating daily undulating periodization and SPP during off-season, pre-season and in-season conditioning. In highperformance sports, high-repetition strength training (>15) should be avoided because it does not provide an adequate training stimulus for gains in muscle cross-sectional area and strength performance. High-volume circuit strength training performed over 2 years negatively affected the development of the power output and maximal strength of the upper extremities in professional rugby players. Indeed, meta-analyses and results with weightlifters, American Football players, and throwers confirm the necessity of the habitual use of >80 % 1 RM: (1) to improve maximal strength during the off-season and in-season in American Football, (2) to reach peak performance in maximal strength and vertical jump power during tapering in track and field, and (3) to produce hypertrophy and strength improvements in advanced athletes. The integration and extent of hypertrophy strength training in in-season conditioning depend on the duration of the contest period, the frequency of the contests, and the proportion of the conditioning program. Based on the literature, 72 h between hypertrophy strength training and strength-power training should be provided to allow for adequate regeneration times and therefore maximal stimulus intensities in training. This conclusion is only valid if the muscle is not trained otherwise during this regeneration phase. Thus, rotating hypertrophy and strength-power sessions in a microcycle during the season is a viable option. Comparative studies in competitive athletes who integrated strength training during pre-season conditioning confirm a tendency for gains in explosive strength and statistically significant improvements in medicine ball throw through SPP but not through daily undulating periodization. These findings indicate that to maximize the speed-strength in the short term (peaking), elite athletes should perform strength-power training twice per week. It is possible to perform a single strength-power session with the method of maximum explosive strength actions moving high-weight loads (90 % 1 repetition maximum [RM]) at least 1–2 days before competition because of the shorter regeneration times and potentiation effects. Compared with ballistic strength training (30 % 1 RM), this method has been shown to provide statistically superior gains in maximal strength, peak power, impulse size, and explosive strength during tapering in track-and-field throwers. The speed-strength performance in drop jumps of strength-trained subjects showed potentiation effects 48–148 h after a single strength-power training session. Regarding neuromuscular performance, plyometric exercises can even be performed after strength-power training on the same day if a minimum rest period of 3 h is provided.
A NUMBER OF KEY CONSIDERATIONS EXIST REGARDING PROTEIN, INCLUDING OVERT REQUIREMENTS, QUALITY, AND DOSING. IN ADDITION, ATHLETES AND RESEARCHERS HAVE CLOSELY EXAMINED THE IMPACT OF PROTEIN AND NUTRIENT TIMING ON ACUTE AND PROLONGED ADAPTATIONS TO DIFFERENT TYPES OF EXERCISE WITH MIXED RESULTS. THE PATTERN OF MEAL AND PROTEIN CONSUMPTION SEEMS TO EXERT AN IMPACT ON CHANGES RELATED TO HEALTH, BODY COMPOSITION, AND MUSCLE PROTEIN SYNTHESIS. PROTEIN IS A KEY NUTRIENT FOR INDIVIDUALS LOOKING TO LOSE WEIGHT, REDUCE THEIR BODY FAT, AND IMPROVE THEIR HEALTH. FINALLY, PROTEIN INTAKE CONTINUES TO BE A KEY VARIABLE FOR ATHLETES LOOKING TO GAIN STRENGTH, POWER, AND FAT-FREE MASS.
BACKGROUND: It has been demonstrated that protein ingestion before sleep increases muscle protein synthesis rates during overnight recovery from an exercise bout. However, it remains to be established whether dietary protein ingestion before sleep can effectively augment the muscle adaptive response to resistance-type exercise training.
OBJECTIVE: Here we assessed the impact of dietary protein supplementation before sleep on muscle mass and strength gains during resistance-type exercise training.
METHODS: Forty-four young men (22 ± 1 y) were randomly assigned to a progressive, 12-wk resistance exercise training program. One group consumed a protein supplement containing 27.5 g of protein, 15 g of carbohydrate, and 0.1 g of fat every night before sleep. The other group received a noncaloric placebo. Muscle hypertrophy was assessed on a whole-body (dual-energy X-ray absorptiometry), limb (computed tomography scan), and muscle fiber (muscle biopsy specimen) level before and after exercise training. Strength was assessed regularly by 1-repetition maximum strength testing.
RESULTS: Muscle strength increased after resistance exercise training to a significantly greater extent in the protein-supplemented (PRO) group than in the placebo-supplemented (PLA) group (+164 ± 11 kg and +130 ± 9 kg, respectively; P < 0.001). In addition, quadriceps muscle cross-sectional area increased in both groups over time (P < 0.001), with a greater increase in the PRO group than in the PLA group (+8.4 ± 1.1 cm(2) vs. +4.8 ± 0.8 cm(2), respectively; P < 0.05). Both type I and type II muscle fiber size increased after exercise training (P < 0.001), with a greater increase in type II muscle fiber size in the PRO group (+2319 ± 368 μm(2)) than in the PLA group (+1017 ± 353 μm(2); P < 0.05).
CONCLUSION: Protein ingestion before sleep represents an effective dietary strategy to augment muscle mass and strength gains during resistance exercise training in young men. This trial was registered at clinicaltrials.gov as NCT02222415.
Skeletal muscle is an integral body tissue playing key roles in strength, performance, physical function, and metabolic regulation. It is essential for athletes to ensure that they have optimal amounts of muscle mass to ensure peak performance in their given sport. However, the role of maintaining muscle mass during weight loss and as we age is an emerging concept, having implications in chronic disease prevention, functional capacity, and quality of life. Higher-protein diets have been shown to: (1) promote gains in muscle mass, especially when paired with resistance training; (2) spare muscle mass loss during caloric restriction; and (3) attenuate the natural loss of muscle mass that accompanies aging. Protein quality is important to the gain and maintenance of muscle mass. Protein quality is a function of protein digestibility, amino acid content, and the resulting amino acid availability to support metabolic function. Whey protein is one of the highest-quality proteins given its amino acid content (high essential, branched-chain, and leucine amino acid content) and rapid digestibility. Consumption of whey protein has a robust ability to stimulate muscle protein synthesis. In fact, whey protein has been found to stimulate muscle protein synthesis to a greater degree than other proteins such as casein and soy. This review examines the existing data supporting the role for protein consumption, with an emphasis on whey protein, in the regulation of muscle mass and body composition in response to resistance training, caloric restriction, and aging.
© 2015 Institute of Food Technologists®
Dietary protein ingestion following exercise increases muscle protein synthesis rates, stimulates net muscle protein accretion, and facilitates the skeletal muscle adaptive response to prolonged exercise training. Furthermore, recent studies show that protein ingestion before and during exercise also increases muscle protein synthesis rates during resistance- and endurance-type exercise. Therefore, protein ingestion before and during prolonged exercise may represent an effective dietary strategy to enhance the skeletal muscle adaptive response to each exercise session by extending the window of opportunity during which the muscle protein synthetic response is facilitated. Protein ingestion during exercise has also been suggested to improve performance capacity acutely. However, recent studies investigating the impact of protein ingestion during exercise on time trial performance, as opposed to time to exhaustion, do not report ergogenic benefits of protein ingestion. Therefore, it is concluded that protein ingestion with carbohydrate during exercise does not further improve exercise performance when compared with the ingestion of ample amounts of carbohydrate only.
Resistance training is a potent stimulus to increase skeletal muscle mass. The muscle protein accretion process depends on a robust synergistic action between protein intake and overload. The intake of protein after resistance training increases plasma amino acids, which results in the activation of signaling molecules leading to increased muscle protein synthesis (MPS) and muscle hypertrophy. Although both essential and non-essential amino acids are necessary for hypertrophy, the intake of free L-leucine or high leucine whole proteins has been specifically shown to increase the initiation of translation that is essential for elevated MPS. The literature supports the use of protein intake following resistance training sessions to enhance MPS; however, less understood are the effects of different protein sources and timing protocols on MPS. The sum of the adaptions from each individual training session are essential to muscle hypertrophy, and thus highlight the importance of an optimal supplementation protocol. The purpose of this review is to present recent findings reported in the literature and discuss the practical application of these results. In that light, new speculations and questions will arise that may direct future investigations. The information and recommendations generated in this review will thereby benefit practicing sport and clinical nutritionists alike.
Circuit resistance training (CRT) performed three times weekly for 40-45 minutes each session increases muscular strength, and both aerobic and anaerobic capacity in untrained individuals with chronic paraplegia. Whether similar CRT is also effective for conditioning of persons with chronic tetraplegia is unknown. In addition, protein supplementation (PS) prior to, and immediately post-exercise has been shown to enhance exercise adaptations.
To investigate whether a modified 40-45 min CRT program will improve fitness attributes in individuals with tetraplegia, and whether these changes are enhanced by PS.
Eleven individuals with chronic tetraplegia underwent six months of CRT performed 3x/wk. Six randomly assigned participants received PS (whey protein: 36-37g) in split doses immediately prior to and after exercise sessions. Others consumed a matched protein dose 24h post-exercise. Measurements of one-repetition maximal (1-RM) strength for six different resistance exercises, arm peak oxygen consumption (VO2peak) and arm anaerobic power (Wingate) were obtained 3 months before (-3mo), at the beginning (0mo), three months into (3mo) and 6 months after (6mo) the beginning of CRT.
1-RM increased by 8-11±6-12% for each successive three month period (p ≤.001-.012) independent of PS group (p=.105). VO2peak increased significantly from 0mo to 6mo with immediate PS (35±29%, p=.020) but failed to reach significance for delayed PS (15±8 %, p=.147). Power drop changes during the Wingate test were also only significant for the immediate PS (median difference 40W, p=.028) and not for delayed (10W, p=.500).
CRT effectively increased muscular strength, aerobic capacity and anaerobic fatigue resistance in persons with chronic tetraplegia. The latter two conditioning benefits were further enhanced by timely PS.
Sparse information exists on the nutrition intake of U.S. military service members in a garrison setting. The purpose of this study was to assess the eating habits of a small group of service members who had not deployed in the preceding 12 months. Nutrition intake was measured using an online food frequency questionnaire and anthropometric measurements taken. Correlations were used to assess relationships between total caloric intake and sex, age, weight, waist circumference, body mass index, rank, marital status, history in a service-specific weight control program, and time in service. There were 39 subjects (18 males, 21 females) enrolled. There was a significant difference in total caloric intake between males and females (p = 0.040). The relationships of total caloric intake to both weight and waist circumference were significant (r = 0.425, p = 0.007 and r = 0.393, p = 0.013). There was a modest relationship between total caloric intake and sex (r = 0.331, p = 0.040) and history in a weight control program (r = -0.313, p = 0.052). There was no significant correlation between body mass index, age, rank, marital status, time in service, and total caloric intake. These relationships may partially explain the eating habits of service members in garrison. Future studies should further assess intake and influential additional factors, such as deployments.
As the incidence rate of lifestyle-related chronic conditions such as cardiovascular disease, obesity, and type 2 diabetes continues to increase, the importance of regular exercise and a healthy diet for improving or maintaining good health is critical. Exercise training is known to improve fitness and many health risk factors, as well as to improve the performance of competitive athletes. It has become increasingly clear, however, that nutrient intake before, during, and after exercise sessions has a powerful influence on the adaptive response to the exercise stimuli. In this review, the science behind nutrient timing will be discussed as it relates to exercise performance, recovery, and training adaptation. Evidence will be provided that validates intake of appropriate nutrients before, during, and immediately after exercise not only to improve exercise performance but also to maximize the training response. Ultimately, the combined response to exercise and proper nutrient intake leads to not only better performance in athletes but also greater health benefits for all exercisers.
We investigated the effects of resistance exercise combined with essential amino acid supplementation on psoas major muscle (PMM) hypertrophy and walking ability in elderly individuals. Twenty-nine healthy elderly individuals were assigned to 3 groups: (1) E (exercise), (2) A3 (exercise combined with 3.0 g of essential amino acid supplementation), and (3) A6 (exercise combined with 6.0 g of essential amino acid supplementation). To evaluate walking ability, the participants underwent the following 3 types of tests: the (1) 10-meter walk (10-W), (2) 10-meter walk involving crossing of obstacles (10-W + O), and (3) 6-minute walk (6M-W) tests. The 6-month training program resulted in significant PMM hypertrophy in all groups independent of amino acid supplementation. The extent of hypertrophy in the participants who took amino acids was dose-dependent, although the differences were not significant. Groups A3 and A6 demonstrated improvements in the 10-W and 10-W + O tests, whereas no improvement was observed in group E, regardless of PMM hypertrophy. Furthermore, group A6 showed an improvement in the 6M-W test. These results suggest that our training program causes PMM hypertrophy, whereas the training program combined with essential amino acid supplementation improves walking ability.
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.
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.
Leucine kinetic and nitrogen balance (NBAL) methods were used to determine the dietary protein requirements of strength athletes (SA) compared with sedentary subjects (S). Individual subjects were randomly assigned to one of three protein intakes: low protein (LP) = 0.86 g protein.kg-1.day-1, moderate protein (MP) = 1.40 g protein.kg-1.day-1, or high protein (HP) = 2.40 g protein.kg-1.day-1 for 13 days for each dietary treatment. NBAL was measured and whole body protein synthesis (WBPS) and leucine oxidation were determined from L-[1-13C]leucine turnover. NBAL data were used to determine that the protein intake for zero NBAL for S was 0.69 g.kg-1.day-1 and for SA was 1.41 g.kg-1.day-1. A suggested recommended intake for S was 0.89 g.kg-1.day-1 and for SA was 1.76 g.kg-1.day-1. For SA, the LP diet did not provide adequate protein and resulted in an accommodated state (decreased WBPS vs. MP and HP), and the MP diet resulted in a state of adaptation [increase in WBPS (vs. LP) and no change in leucine oxidation (vs. LP)]. The HP diet did not result in increased WBPS compared with the MP diet, but leucine oxidation did increase significantly, indicating a nutrient overload. For S the LP diet provided adequate protein, and increasing protein intake did not increase WBPS. On the HP diet leucine oxidation increased for S. These results indicated that the MP and HP diets were nutrient overloads for S. There were no effects of varying protein intake on indexes of lean body mass (creatinine excretion, body density) for either group. In summary, protein requirements for athletes performing strength training are greater than for sedentary individuals and are above current Canadian and US recommended daily protein intake requirements for young healthy males.
The aim of this study was to determine if a change in protein/carbohydrate ratio influences plasma steroid hormone concentrations. There is little information about the effects of specific dietary components on steroid hormone metabolism in humans. Testosterone concentrations in seven normal men were consistently higher after ten days on a high carbohydrate diet (468 +/- 34 ng/dl, mean +/- S.E.) than during a high protein diet (371 +/- 23 ng/dl, p less than 0.05) and were accompanied by parallel changes in sex hormone binding globulin (32.5 +/- 2.8 nmol/l vs. 23.4 +/- 1.6 nmol/l respectively, p less than 0.01). By contrast, cortisol concentrations were consistently lower during the high carbohydrate diet than during the high protein diet (7.74 +/- 0.71 micrograms/dl vs. 10.6 +/- 0.4 micrograms/dl respectively, p less than 0.05), and there were parallel changes in corticosteroid binding globulin concentrations (635 +/- 60 nmol/l vs. 754 +/- 31 nmol/l respectively, p less than 0.05). The diets were equal in total calories and fat. These consistent and reciprocal changes suggest that the ratio of protein to carbohydrate in the human diet is an important regulatory factor for steroid hormone plasma levels and for liver-derived hormone binding proteins.
To examine the effect of carbohydrate and/or protein supplements on the hormonal state of the body after weight-training exercise, nine experienced male weight lifters were given water (Control) or an isocaloric carbohydrate (CHO; 1.5 g/kg body wt), protein (PRO; 1.38 g/kg body wt), or carbohydrate-protein (CHO/PRO; 1.06 g carbohydrate/kg body wt and 0.41 g protein/kg) supplement immediately and 2 h after a standardized weight-training workout. Venous blood samples were drawn before and immediately after exercise and during 8 h of recovery. Exercise induced elevations in lactate, glucose, testosterone, and growth hormone. CHO and CHO/PRO stimulated higher insulin concentrations than PRO and Control. CHO/PRO led to an increase in growth hormone 6 h postexercise that was greater than PRO and Control. Supplements had no effect on insulin-like growth factor I but caused a significant decline in testosterone. The decline in testosterone, however, was not associated with a decline in luteinizing hormone, suggesting an increased clearance of testosterone after supplementation. The results suggest that nutritive supplements after weight-training exercise can produce a hormonal environment during recovery that may be favorable to muscle growth by stimulating insulin and growth hormone elevations.
Manipulation of resistance exercise variables (i.e., intensity, volume, and rest periods) affects the endocrine response to exercise; however, the influence of dietary nutrients on basal and exercise-induced concentrations of hormones is less understood. The present study examined the relationship between dietary nutrients and resting and exercise-induced blood concentrations of testosterone (T) and cortisol (C). Twelve men performed a bench press exercise protocol (5 sets to failure using a 10-repetitions maximum load) and a jump squat protocol (5 sets of 10 repetitions using 30% of each subject's 1-repetition maximum squat) with 2 min of rest between all sets. A blood sample was obtained at preexercise and 5 min postexercise for determination of serum T and C. Subjects also completed detailed dietary food records for a total of 17 days. There was a significant (P < or = 0.05) increase in postexercise T compared with preexercise values for both the bench press (7.4%) and jump squat (15.1%) protocols; however, C was not significantly different from preexercise concentrations. Significant correlations were observed between preexercise T and percent energy protein (r = -0.71), percent energy fat (r = 0.72), saturated fatty acids (g.1,000 kcal-1.day-1; r = 0.77), monounsaturated fatty acids (g.1,000 kcal-1.day-1; r = 0.79, the polyunsaturated fat-to-saturated fat ratio (r = -0.63), and the protein-to-carbohydrate ratio (r = -0.59). There were no significant correlations observed between any nutritional variables and preexercise C or the absolute increase in T and C after exercise. These data confirm that high-intensity resistance exercise results in elevated postexercise T concentrations. A more impressive finding was that dietary nutrients may be capable of modulating resting concentrations of T.
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.
The provision of carbohydrate (CHO) supplements following resistance exercise attenuated muscle protein (PRO) degradation (Roy et al. J. Appl. Physiol. 82:1882-1888, 1997). The addition of PRO may have a synergistic effect upon whole body protein balance by increasing synthesis (Biolo et al. Am. J. Physiol. 273:E122-E129, 1997).
To determine if the macronutrient composition of a postexercise beverage would alter muscle anabolism and/or catabolism following resistance exercise.
We provided isoenergetic CHO (1 g x kg(-1)) and CHO/PRO/FAT supplements and placebo (PL) immediately (t = 0 h) and 1 h (t = + 1 h) following resistance exercise (9 exercises/3 sets/80% 1 RM) to 10 young, healthy, resistance-trained males. Whole body leucine turnover was determined from L-[1-13C]leucine kinetics at approximately 4 h postexercise.
No differences were observed for urinary 3-methylhistidine or urea nitrogen excretion between the trials. Leucine flux was significantly elevated at approximately 4 h postexercise for both CHO/PRO/FAT (177.59+/-12.68 micromol x kg(-1) x h(-1)) and CHO (156.18+/-7.77 micromol x kg(-1) x h(-1)) versus PL (126.32+/-10.51 micromol x kg(-1) x h(-1)) (P < 0.01). Whole body leucine oxidation was elevated at approximately 4 h for CHO/PRO/FAT (29.50+/-3.34 micromol x kg(-1) h(-1)) versus CHO (16.32+/-2.33 micromol x kg(-1) x h(-1)) (P < 0.01) and PL (21.29+/-2.54 micromol x kg(-1) x h(-1)) (P < 0.05). Nonoxidative leucine disposal (NOLD) was significantly elevated at approximately 4 h for both CHO/PRO/FAT (148.09+/-10.37 micromol x kg(-1) x h(-1)) and CHO (139.86+/-7.02 micromol x kg(-1) x h(-1)) versus PL (105.03+/-8.97 micromol x kg(-1) x h(-1)) (P < 0.01).
These results suggest that consumption of either CHO or CHO/PRO/FAT immediately and 1 h following a resistance training bout increased NOLD as compared with a placebo.
Seventy-three healthy, male subjects randomly divided into 3 groups participated in a study to determine the effects of 2 high-calorie nutritional supplements on body composition, body segment circumferences, and muscular strength following a resistance-training (RT) program.
In addition to their normal diets group 1 (CHO/PRO; n=26) consumed a 8.4 Mj x day(-1) (2010 kcal) high calorie, high protein supplement containing 356 g carbohydrate and 106 g protein. Group 2 (CHO; n=25) consumed a carbohydrate supplement that was isocaloric with CHO/PRO. Group 3 (CTRL; n=22) received no supplement and served as a control. All subjects were placed on a 4-day x week(-1) RT program for 8 weeks.
Dietary analysis revealed no significant differences in total energy consumption or nutrients at any time in the non-supplemented diets of the 3 groups. Significant (p= or <0.05) increases in body mass (BM) and fat-free mass (FFM) were observed in CHO/PRO and CHO compared to CTRL. Mean (+/- SD) increases in BM were 3.1+/-3.1 kg and 3.1+/-2.2 kg, respectively. Fat-free mass significantly (p= or <0.05) increased 2.9+/-3.4 kg in CHO/PRO and 3.4+/-2.5 kg in CHO. Muscular strength, as measured by a one-repetition maximum in the bench press, leg press, and lat-pull down increased significantly (p= or <0.05) in all groups. No significant differences in strength measures were observed among groups following training.
Results indicate that high-calorie supplements are effective in increasing BM and FFM when combined with RT. However, once individual protein requirements are met, energy content of the diet has the largest effect on body composition.
Debilitating injury is accompanied by hypercortisolemia, muscle wasting, and disruption of the normal anabolic response to food. We sought to determine whether acute hypercortisolemia alters muscle protein metabolism following ingestion of a potent anabolic stimulus: essential amino acids (EAA). A 27-h infusion (80 microg. kg(-1). h(-1)) of hydrocortisone sodium succinate mimicked cortisol (C) levels accompanying severe injury (>30 microg/dl), (C + AA; n = 6). The control group (AA) received intravenous saline (n = 6). Femoral arteriovenous blood samples and muscle biopsies were obtained during a primed (2.0 micromol/kg) constant infusion (0.05 micromol. kg(-1). min(-1)) of l-[ring-(2)H(5)]phenylalanine before and after ingestion of 15 g of EAA. Hypercortisolemia [36.5 +/- 2.1 (C + AA) vs. 9.0 +/- 1.0 microg/dl (AA)] increased postabsorptive arterial, venous, and muscle intracellular phenylalanine concentrations. Hypercortisolemia also increased postabsorptive and post-EAA insulin concentrations. Net protein balance was blunted (40% lower) following EAA ingestion but remained positive for a greater period of time (60 vs. 180 min) in the C + AA group. Thus, although differences in protein metabolism were evident, EAA ingestion improved muscle protein anabolism during acute hypercortisolemia and may help minimize muscle loss following debilitating injury.
This investigation examined chronic alteration of the acute hormonal response associated with liquid carbohydrate (CHO) and/or essential amino acid (EAA) ingestion on hormonal and muscular adaptations following resistance training. Thirty-two untrained young men performed 12 weeks of resistance training twice a week, consuming ~675 ml of either, a 6% CHO solution, 6 g EAA mixture, combined CHO + EAA supplement or placebo (PLA). Blood samples were obtained pre- and post-exercise (week 0, 4, 8, and 12), for determination of glucose, insulin, and cortisol. 3-Methylhistidine excretion and muscle fibre cross-sectional area (fCSA) were determined pre- and post-training. Post-exercise cortisol increased (P<0.05) during each training phase for PLA. No change was displayed by EAA; CHO and CHO + EAA demonstrated post-exercise decreases (P<0.05). All groups displayed reduced pre-exercise cortisol at week 12 compared to week 0 (P<0.05). Post-exercise insulin concentrations showed no change for PLA; increases were observed for the treatment groups (P<0.05), which remained greater for CHO and CHO + EAA (P<0.001) than PLA. EAA and CHO ingestion attenuated 3-methylhistidine excretion 48 h following the exercise bout. CHO + EAA resulted in a 26% decrease (P<0.01), while PLA displayed a 52% increase (P<0.01). fCSA increased across groups for type I, IIa, and IIb fibres (P<0.05), with CHO + EAA displaying the greatest gains in fCSA relative to PLA (P<0.05). These data indicate that CHO + EAA ingestion enhances muscle anabolism following resistance training to a greater extent than either CHO or EAA consumed independently. The synergistic effect of CHO + EAA ingestion maximises the anabolic response presumably by attenuating the post-exercise rise in protein degradation.
This study examined 10 wks of resistance training and the ingestion of supplemental protein and amino acids on muscle performance and markers of muscle anabolism. Nineteen untrained males were randomly assigned to supplement groups containing either 20 g protein (14 g whey and casein protein, 6 g free amino acids) or 20 g dextrose placebo ingested 1 h before and after exercise for a total of 40 g/d. Participants exercised 4 times/wk using 3 sets of 6-8 repetitions at 85-90% of the one repetition maximum. Data were analyzed with two-way ANOVA (p < 0.05). The protein supplement resulted in greater increases in total body mass, fat-free mass, thigh mass, muscle strength, serum IGF-1, IGF-1 mRNA, MHC I and IIa expression, and myofibrillar protein. Ten-wks of resistance training with 20 g protein and amino acids ingested 1 h before and after exercise is more effective than carbohydrate placebo in up-regulating markers of muscle protein synthesis and anabolism along with subsequent improvements in muscle performance.
Some studies report greater muscle hypertrophy during resistance exercise (RE) training from supplement timing (i.e., the strategic consumption of protein and carbohydrate before and/or after each workout). However, no studies have examined whether this strategy provides greater muscle hypertrophy or strength development compared with supplementation at other times during the day. The purpose of this study was to examine the effects of supplement timing compared with supplementation in the hours not close to the workout on muscle-fiber hypertrophy, strength, and body composition during a 10-wk RE program.
In a single-blind, randomized protocol, resistance-trained males were matched for strength and placed into one of two groups; the PRE-POST group consumed a supplement (1 g x kg(-1) body weight) containing protein/creatine/glucose immediately before and after RE. The MOR-EVE group consumed the same dose of the same supplement in the morning and late evening. All assessments were completed the week before and after 10 wk of structured, supervised RE training. Assessments included strength (1RM, three exercises), body composition (DEXA), and vastus lateralis muscle biopsies for determination of muscle fiber type (I, IIa, IIx), cross-sectional area (CSA), contractile protein, creatine (Cr), and glycogen content.
PRE-POST demonstrated a greater (P < 0.05) increase in lean body mass and 1RM strength in two of three assessments. The changes in body composition were supported by a greater (P < 0.05) increase in CSA of the type II fibers and contractile protein content. PRE-POST supplementation also resulted in higher muscle Cr and glycogen values after the training program (P < 0.05).
Supplement timing represents a simple but effective strategy that enhances the adaptations desired from RE-training.
This study examined how a high-protein diet affected nitrogen balance and protein turnover during an exercise-induced energy deficit.
Twenty-two men completed a 4-d (D1-4) baseline period (BL) of an energy balance diet while maintaining usual physical activity level, followed by 7 d (D5-11) of 1000 kcal.d increased energy expenditure via exercise (50-65% V O2peak). One group consumed 0.9 g of protein per kilogram per day and maintained energy balance throughout the 11-d intervention (BAL, N = 8). The other two groups consumed their BL energy intake throughout the 11 days, resulting in a 7-d, 1000-kcal.d energy deficit. These groups consumed either 0.9 g of protein per kilogram per day (DEF, N = 7) or 1.8 g of protein per kilogram per day (DEF-HP, N = 7). Mean nitrogen balance (NB), calculated per kilogram of fat-free mass (FFM), was determined for BL, days 5-8 (EX1), and days 9-11 (EX2). Whole-body protein turnover was derived from phenylalanine and tyrosine kinetics assessed while fasting at rest on days 4, 7, and 12, using a priming dose of L-[ring-N]tyrosine and a 4-h, primed, continuous infusion of L-[N]phenylalanine and L-[ring-H4]tyrosine.
DEF experienced a decrease in NB from BL to EX 1 that was maintained in EX 2. No changes in NB occurred for BAL or DEF-HP over time. No within- or between-group differences were found over time for Phe flux (Qp), conversion rate of Phe to Tyr (Qpt), or the derived protein synthesis value (Sp).
Increased dietary protein maintained NB during exercise-induced energy deficit, but this did not impact resting whole-body protein turnover.
Physiological Aspects of Sport Training and Performance, Second Edition, updates and expands on the popular first edition, providing an in-depth discussion of physiological adaptation to exercise. Students will learn the importance of an evidence-based approach in prescribing exercise, while sports medicine professionals and health care providers will appreciate using the text as a primary reference on conditioning and performance of athletes. A range of topics are covered, including environmental influences on performance, hydration status, sport nutrition, sport supplements, and performance-enhancing drugs. The book is focused on physiological adaptation to exercise with a goal of providing practical applications to facilitate exercise prescriptions for a variety of athletes.
Physiological Aspects of Sport Training and Performance, Second Edition, is organized into five parts. The first part examines physiological adaptation and the effects of various modes of training on biochemical, hormonal, muscular, cardiovascular, neural, and immunological adaptations. The second part covers principles of exercise training and prescription. The third part discusses nutrition, hydration status, sport supplementation, and performance-enhancing drugs. The fourth part focuses on environmental factors and their influence on sport performance. The fifth and final part is focused on how certain medical and health conditions influence sport performance.
Updates in this second edition focus on cutting-edge knowledge in sport science and sports medicine, including the latest information on physiological adaptations to exercise; current trends for training for power, speed, and agility; eye-opening discussions on sport supplementation and performance-enhancing drugs; data on training with medical conditions such as diabetes and exercise-induced bronchospasm; and groundbreaking information on training in heat and cold and at altitude. In addition, new chapters offer a practical approach to the yearly training program and sudden death in sport.
This online edition of the text includes access to videos of over 40 drills being performed in their entirety, including a dynamic warm-up routine video features 10 warm-up exercises.
The purpose of this study was to examine the effects of amino acid supplementation on muscular strength, power, and high-intensity endurance during short-term resistance training overreaching. Seventeen resistance-trained men were randomly assigned to either an amino acid (AA) or placebo (P) group and underwent 4 weeks of total-body resistance training consisting of two 2-week phases of overreaching (phase 1: 3 X 8-12 repetitions maximum [RM], 8 exercises; phase 2: 5 X 3-5RM, 5 exercises). Muscle strength, power, and high-intensity endurance 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 P (5.2 and 3.4 kg, respectively) but not in AA, and significant increases in 1RM squat and bench press were observed at T3-T5 in both groups. A decrease in the ballistic bench press peak power was observed at T3 in P but not AA. The fatigue index during the 20-repetition jump squat assessment did not change in the P group at T3 and T5 (fatigue index = 18.6 and 18.3%, respectively) whereas a trend for reduction was observed in the AA group (p = 0.06) at T3 (12.8%) but not T5 (15.2%; p = 0.12). These results indicate that the initial impact of high-volume resistance training overreaching reduces muscle strength and power, and it appears that these reductions are attenuated with amino acid supplementation. In addition, an initial high-volume, moderate-intensity phase of overreaching followed by a higher intensity moderate-volume phase appears to be very effective for enhancing muscle strength in resistance-trained men.
Aggressive and early use of nutritional support therapies in critically ill patients represents a major advance in critical care medicine. The net protein catabolism and erosion of protein stores which is characteristic of the metabolic response to injury results in significant added morbidity and mortality in critical care units. The early administration of appropriate protein and energy in support of enhanced demands will maintain host defense and preserve organ function, thus, allowing time for stabilization of clinical status while life support strategies are implemented. In all circumstances, protein, vitamins, minerals, and nonprotein calories must be provided within fluid and electrolyte restrictions and in conjunction with optimal hemodynamic and pulmonary support.
The effect of an iv load of individual amino acids (alanine, arginine, histidine, leucine, phenylalanine, and valine) on serum prolactin (Prl) and growth hormone (GH) concentrations was studied in healthy adult males (n = 5). A rise in both, Prl and GH with a maximal increment of 15.9 +/- 6.7 (SE) ng/ml, and 12.4 +/- 4.9 ng/ml above basal levels, respectively, (P less than 0.05) was observed after iv arginine. Following iv phenylalanine the mean peak level of Prl rose from 9.9 +/- 3.5 to 29.9 +/- 7.3 ng/ml (P less than 0.01), whereas GH concentration remained unchanged. Iv leucine however induced an immediate rise in GH, but not in serum Prl. Serum concentrations of both, Prl and GH, failed to increase upon the infusion of either alanine or histidine or valine. Additional somatostatin administration starting prior to amino acid infusion diminished the amino acid induced increase of both Prl and GH release.
We assessed the hormonal status of adult female volunteers before and during a 3-wk period of weight gain induced by mixed diet overfeeding. Forty-six percent of the 4.3-kg average weight gain experienced by these subjects consisted of lean body mass (LBM) and it is of interest that there were also increases in plasma Somatomedin-C/Insulin-like Growth Factor (SM-C/IGF-1) and testosterone concentrations as well as insulin. We suggest that it was the combined anabolic effect of these three hormones that facilitated the increase in LBM. Of the other assays done, increases were recorded for urinary 17-ketosteroids, 17-hydroxysteroids, epinephrine, and creatinine, whereas there were no changes in serum cortisol or triiodothyronine (T3), or urine norepinephrine; serum thyroxine (T4) fell slightly. Thus it appears that energy surfeit as well as energy deficit (reported by others) has an effect on blood hormone concentrations.
In Reply.—
I appreciate the comments by Kovach and Huerta.Despite the widespread use of nutritional assessment techniques in the determination of malnutrition, there is no universally applicable method to assess accurately the nutriture of all patients.1 Standards for serum albumin reflect a statistical distribution of normal values for a large group of ages, sexes, and races. For any given person, the true normal value of laboratory determinations may significantly deviate from the standard. Anthropometric measurements (such as, triceps skinfold thickness, mid-arm circumference, height, and weight) have been standardized for middle-aged persons and may not be applicable to the extreme of ages, either the elderly or the preadolescent. It has been noted, for example, that lean body mass declines with age.2 New techniques using specific T-lymphocyte counts, radioisotopic assessment of protein catabolism, and dynamanometric measurement of lean body mass may add sophistication to current methods in assessing visceral
The use of nonanabolic nutritional supplements for the sake of improving athletic performance is common, and the types of supplements used can have significant implications for the medical care of athletes. This review will address the most common and most controversial nonanabolic nutritional supplements, including recommendations regarding their use. Many supplements are marketed and promoted based on various theoretical benefits, often derived from limited animal studies, without any basis for recommending their human use. Physicians are trained to not recommend a nutritional supplement unless it is known to be effective, whereas athletes are oriented toward trying any supplement or ergogenic aid as long as it is safe, with the hope that it may be effective. The built-in error in most study designs is larger than the difference between winning and not qualifying at elite levels of competition, such that research may not always answer the questions raised by athletes. An honest discussion of the limitations of most supplements, and acknowledgment that some supplements may work some of the time in some athletes, may lead the physician to be more credible and useful to athletes in providing medical care and guidance that support their desire to improve their performance.
The purpose of this study was to examine the effects of amino acid supplementation on muscular strength, power, and high-intensity endurance during short-term resistance training overreaching. Seventeen resistance-trained men were randomly assigned to either an amino acid (AA) or placebo (P) group and underwent 4 weeks of total-body resistance training consisting of two 2-week phases of overreaching (phase 1: 3 x 8-12 repetitions maximum [RM], 8 exercises; phase 2: 5 x 3-5 RM, 5 exercises). Muscle strength, power, and high-intensity endurance 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 P (5.2 and 3.4 kg, respectively) but not in AA, and significant increases in 1 RM squat and bench press were observed at T3-T5 in both groups. A decrease in the ballistic bench press peak power was observed at T3 in P but not AA. The fatigue index during the 20-repetition jump squat assessment did not change in the P group at T3 and T5 (fatigue index = 18.6 and 18.3%, respectively) whereas a trend for reduction was observed in the AA group (p = 0.06) at T3 (12.8%) but not T5 (15.2%; p = 0.12). These results indicate that the initial impact of high-volume resistance training overreaching reduces muscle strength and power, and it appears that these reductions are attenuated with amino acid supplementation. In addition, an initial high-volume, moderate-intensity phase of overreaching followed by a higher intensity, moderate-volume phase appears to be very effective for enhancing muscle strength in resistance-trained men.
The purpose of this study was to assess the dietary intakes and behaviors of male and female collegiate athletes. Athletes (n =345) at a NCAA Division I university completed an anonymous questionnaire. T-tests, chi(2) statistic, and ANOVA were used to assess gender and sport differences. Multiple linear regression was used to assess gender differences in nutrient intakes, controlling for energy intake and to examine the relationships between desired weight change, dietary behaviors, and nutrient intakes. Only 15 % and 26 % of athletes had adequate intakes of carbohydrate and protein, respectively, based on recommendations for athletes. Males were more likely to exceed the Dietary Guidelines for fat, saturated fat, cholesterol, and sodium than females. Sixty-two percent of female athletes wanted to lose at least 5 lbs compared to 23 % of males. The desire to lose weight was associated with decreased energy and macronutrient consumption, but not with inadequate micronutrient intakes.
The objective of this study is to evaluate the dietary practices of 28 football athletes on a National Collegiate Athletic Association (NCAA) Division I team using 3-day diet records. Student athletes completed 3-day diet records at 2 individual points of time, when no training table was available. Diet records were evaluated and were compared with the Third National Health and Nutrition Survey (NHANES III) data for the same ages and gender group. No differences in dietary practices of collegiate football athletes were observed when compared with data for the same ages and gender group culled from NHANES III. Inadequacies in energy intake for activity level were significant (p < 0.05). Influences of fad dieting trends were noted when the diets were mapped onto the United States Department of Agriculture (USDA) food guide pyramid. Changes in diet would be necessary to sustain the activity level of these athletes.
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.
Dietitians of Canada and the American College of Sports Medicine Position stand: Nutrition and athletic performance
- American Dietetic Association
American Dietetic Association, Dietitians of Canada and the American College of Sports Medicine. Position stand: Nutrition and
athletic performance. Med. Sci. Sports Exer. 2000; 32:2130-2145.
Position stand: Nutrition and athletic performance
American Dietetic Association, Dietitians of Canada and the American College of Sports Medicine. Position stand: Nutrition and
athletic performance. Med. Sci. Sports Exer. 2000; 32:2130-2145.
When food becomes a drug: Nonanabolic nutritional supplement use in athletics
- T L Schenk
- C D Costley
Schenk TL, Costley CD. When food becomes a drug: Nonanabolic nutritional supplement use in athletics. Amer. J. Sports Med.
2002; 30:907-916.