***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: To assess age and gender differences in muscle strength , isometric , concentric ( Con ) , and eccentric ( Ecc ) peak torque was measured in the knee extensors at a slow ( 0.52 rad/s ) and fast ( 3.14 rad/s ) velocity in 654 subjects ( 346 men and 308 women , aged 20 - 93 yr ) from the Baltimore Longitudinal Study of Aging . Regression analysis revealed significant ( P < 0.001 ) age-related reductions in Con and Ecc peak torque for men and women at both velocities , but no differences were observed between the gender groups or velocities . Age explained losses in Con better than Ecc peak torque , accounting for 30 % ( Con ) vs. 19 % ( Ecc ) of the variance in men and 28 % ( Con ) vs. 11 % ( Ecc ) in women . To assess age and gender differences in the ability to store and utilize elastic energy , the stretch-shortening cycle was determined in a subset of subjects ( n = 47 ) . The older women ( mean age = 70 yr ) showed a significantly greater enhancement in the stretch-shortening cycle , compared with men of similar age ( P < 0.01 ) and compared with younger men and women ( each P < 0.05 ) . Both men and women showed significant declines in muscle quality for Con peak torque ( P < 0.01 ) , but no gender differences were observed . Only the men showed a significant decline in muscle quality ( P < 0.001 ) for Ecc peak torque . Thus both men and women experience age-related losses in isometric , Con , and Ecc knee extensor peak torque ; however , age accounted for less of the variance in Ecc peak torque in women , and women tend to better preserve muscle quality with age for Ecc peak torque . In addition , older women have an enhanced capacity to store and utilize elastic energy compared with similarly aged men as well as with younger women and men We recently showed that resistance exercise and ingestion of essential amino acids with carbohydrate ( EAA+CHO ) can independently stimulate mammalian target of rapamycin ( mTOR ) signaling and muscle protein synthesis in humans . Providing an EAA+CHO solution postexercise can further increase muscle protein synthesis . Therefore , we hypothesized that enhanced mTOR signaling might be responsible for the greater muscle protein synthesis when leucine-enriched EAA+CHOs are ingested during postexercise recovery . Sixteen male subjects were r and omized to one of two groups ( control or EAA+CHO ) . The EAA+CHO group ingested the nutrient solution 1 h after resistance exercise .  mTOR signaling was assessed by immunoblotting from repeated muscle biopsy sample s. Mixed muscle fractional synthetic rate ( FSR ) was measured using stable isotope techniques . Muscle protein synthesis and 4E-BP1 phosphorylation during exercise were significantly reduced ( P < 0.05 ) . Postexercise FSR was elevated above baseline in both groups at 1 h but was even further elevated in the EAA+CHO group at 2 h postexercise ( P < 0.05 ) . Increased FSR was associated with enhanced phosphorylation of mTOR and S6K1 ( P < 0.05 ) . Akt phosphorylation was elevated at 1 h and returned to baseline by 2 h in the control group , but it remained elevated in the EAA+CHO group ( P < 0.05 ) . 4E-BP1 phosphorylation returned to baseline during recovery in control but became elevated when EAA+CHO was ingested ( P < 0.05 ) . eEF2 phosphorylation decreased at 1 and 2 h postexercise to a similar extent in both groups ( P < 0.05 ) . Our data suggest that enhanced activation of the mTOR signaling pathway is playing a role in the greater synthesis of muscle proteins when resistance exercise is followed by EAA+CHO ingestion Systematic review s ( SRs ) are an increasingly popular evidence -based tool and are often used to answer complex research questions across many different research domains . Early SR methodology was advanced by social scientists , and the term meta- analysis was coined by a social scientist who also conducted research in psychology . SRs have recently become popular in healthcare and are likely to be beneficial in any field . The aim of this report is to highlight issues in SR conduct with a focus on the field of nutrition and to make recommendations on improving SR conduct in this area . Development of the research question is probably the most important step in conducting an SR . The 4 main components of an answerable question are 1 ) the patient , population , or problem ; 2 ) the intervention , independent variable , or exposure ; 3 ) the comparators ; and 4 ) the dependent variables or outcomes of interest . The question will be used to determine the optimal methods for conducting the SR . SRs often include study design s beyond r and omized trials and do not always include a meta- analysis of the results . Other topics explored include underst and ing and interpreting discordant review s and the importance of reporting tools [ eg , QUality Of Reporting Of Meta-analyses ( QUOROM Statement ) or CONsoli date d St and ards Of Reporting of Trials ( CONSORT Statement ) ] . Recommendations are then provided , such as developing a capacity-building program , search ing the primary literature for research gaps , and extending reporting tools such as the QUOROM Statement to the field of nutrition We examined the response of net muscle protein synthesis to ingestion of amino acids after a bout of resistance exercise . A primed , constant infusion ofl- [ ring-2H5]phenylalanine was used to measure net muscle protein balance in three male and three female volunteers on three occasions . Subjects consumed in r and om order 1 liter of 1 ) a mixed amino acid ( 40 g ) solution ( MAA ) , 2 ) an essential amino acid ( 40 g ) solution ( EAA ) , and 3 ) a placebo solution ( PLA ) . Arterial amino acid concentrations increased ∼150 - 640 % above baseline during ingestion of MAA and EAA . Net muscle protein balance was significantly increased from negative during PLA ingestion ( -50 ± 23 nmol ⋅ min-1 ⋅ 100 ml leg volume-1 ) to positive during MAA ingestion ( 17 ± 13 nmol ⋅ min-1 ⋅ 100 ml leg volume-1 ) and EAA ( 29 ± 14 nmol ⋅ min-1 ⋅ 100 ml leg volume-1 ; P < 0.05 ) . Because net balance was similar for MAA and EAA , it does not appear necessary to include nonessential amino acids in a formulation design ed to elicit an anabolic response from muscle after exercise . We concluded that ingestion of oral essential amino acids results in a change from net muscle protein degradation to net muscle protein synthesis after heavy resistance exercise in humans similar to that seen when the amino acids were infused BACKGROUND The anabolic effect of resistance exercise is enhanced by the provision of dietary protein . OBJECTIVES We aim ed to determine the ingested protein dose response of muscle ( MPS ) and albumin protein synthesis ( APS ) after resistance exercise . In addition , we measured the phosphorylation of c and i date signaling proteins thought to regulate acute changes in MPS . DESIGN Six healthy young men reported to the laboratory on 5 separate occasions to perform an intense bout of leg-based resistance exercise . After exercise , participants consumed , in a r and omized order , drinks containing 0 , 5 , 10 , 20 , or 40 g whole egg protein .  Protein synthesis and whole-body leucine oxidation were measured over 4 h after exercise by a primed constant infusion of [1-(13)C]leucine . RESULTS MPS displayed a dose response to dietary protein ingestion and was maximally stimulated at 20 g. The phosphorylation of ribosomal protein S6 kinase ( Thr(389 ) ) , ribosomal protein S6 ( Ser(240/244 ) ) , and the epsilon-subunit of eukaryotic initiation factor 2B ( Ser(539 ) ) were unaffected by protein ingestion . APS increased in a dose-dependent manner and also reached a plateau at 20 g ingested protein . Leucine oxidation was significantly increased after 20 and 40 g protein were ingested . CONCLUSIONS Ingestion of 20 g intact protein is sufficient to maximally stimulate MPS and APS after resistance exercise . Phosphorylation of c and i date signaling proteins was not enhanced with any dose of protein ingested , which suggested that the stimulation of MPS after resistance exercise may be related to amino acid availability . Finally , dietary protein consumed after exercise in excess of the rate at which it can be incorporated into tissue protein stimulates irreversible oxidation Our purpose was to assess muscular adaptations during 6 weeks of resistance training in 36 males r and omly assigned to supplementation with whey protein ( W ; 1.2 g/kg/day ) , whey protein and creatine monohydrate  ( WC ; 0.1 g/kg/day ) , or placebo ( P ; 1.2 g/kg/day maltodextrin ) . Measures included lean tissue mass by dual energy x-ray absorptiometry , bench press and squat strength ( 1-repetition maximum ) , and knee extension/flexion peak torque . Lean tissue mass increased to a greater extent with training in WC compared to the other groups , and in the W compared to the P group ( p < .05 ) . Bench press strength increased to a greater extent for WC compared to W and P ( p < .05 ) . Knee extension peak torque increased with training for WC and W ( p < .05 ) , but not for P. All other measures increased to a similar extent across groups . Continued training without supplementation for an additional 6 weeks result ed in maintenance of strength and lean tissue mass in all groups . Males that supplemented with whey protein while resistance training demonstrated greater improvement in knee extension peak torque and lean tissue mass than males engaged in training alone . Males that supplemented with a combination of whey protein and creatine had greater increases in lean tissue mass and bench press than those who supplemented with only whey protein or placebo . However , not all strength measures were improved with supplementation , since subjects who supplemented with creatine and /or whey protein had similar increases in squat strength and knee flexion peak torque compared to subjects who received placebo The purpose of this study was to determine the effects of 6 wk of essential amino acid ( EAA ) supplementation on body composition and exercise performance in untrained women ( n = 21 ) . Subjects were r and omly assigned to a placebo ( cellulose ) or an EAA ( average daily dose of 18.3 g of EAAs in pill form ) group . Each subject participated in aerobic and heavy-resistance training three times per week . Body composition was assessed via dual x-ray absorptiometry analysis . Muscular endurance was determined via treadmill time to exhaustion , and strength was assessed by the total amount of weight lifted for one set to exhaustion at an estimated 12 repetitions maximum . No changes occurred in either group for body weight , lean body mass , fat mass , or bone mineral content . Treadmill time to exhaustion ( TTE ) improved significantly ( P < 0.05 ) in the EAA group ( mean + /- SD ; pre-TTE = 13.15 + /- 3.67 min , post-TTE = 14 . 73 + /- 4.26 min ) , whereas the placebo group did not change significantly . The total weight lifted at the subject 's maximum 12 repetitions did not significantly change in either group . In previously untrained individuals , the ingestion of EAAs combined with aerobic and heavy-resistance training for 6 wk did not have a significant effect on body composition or muscular strength ; however , aerobic muscular endurance increased significantly This study was design ed to determine the response of muscle protein to the bolus ingestion of a drink containing essential amino acids and carbohydrate  after resistance exercise . Six subjects ( 3 men , 3 women ) r and omly consumed a treatment drink ( 6 g essential amino acids , 35 g sucrose ) or a flavored placebo drink 1 h or 3 h after a bout of resistance exercise on two separate occasions . We used a three-compartment model for determination of leg muscle protein kinetics . The model involves the infusion of ring-(2)H(5)-phenylalanine , femoral arterial and venous blood sampling , and muscle biopsies . Phenylalanine net balance and muscle protein synthesis were significantly increased above the predrink and corresponding placebo value ( P < 0.05 ) when the drink was taken 1 or 3 h after exercise but not when the placebo was ingested at 1 or 3 h. The response to the amino acid-carbohydrate drink produced similar anabolic responses at 1 and 3 h. Muscle protein breakdown did not change in response to the drink . We conclude that essential amino acids with carbohydrates stimulate muscle protein anabolism by increasing muscle protein synthesis when ingested 1 or 3 h after resistance exercise The purpose of this study was to examine the effects of a drink containing creatine , amino acids , and protein vs. a carbohydrate placebo on body composition , strength , muscular endurance , and anaerobic performance before and after 10 weeks of resistance training . Fifty-one men ( mean ± SD ; age : 21.8 ± 2.9 years ) were r and omly assigned to either the test drink ( TEST ; n = 23 ) or the placebo ( PLAC ; n = 28 ) and performed two 30-second Win-gate Anaerobic Tests for determination of peak power ( PP ) and mean power ( MP ) , were weighed underwater for percent body fat ( % fat ) and fat-free mass ( FFM ) , and were tested for 1 repetition maximum ( 1RM ) dynamic constant external resistance strength and muscular endurance ( END ; number of repetitions performed with 80 % of 1R 
    Output:
    
Protein supplementation increases muscle mass and strength gains during prolonged resistance-type exercise training in both younger and older subjects