D’Souza1, Marworth1, Figueiredo1, Della Gatta2, Petersen3, Mitchell1 Cameron-Smith1
– 46 healthy older men aged 60–75 (69.0 ± 0.55 years, 85.9 ± 1.8 kg, 176.8 ± 1.0 cm)
(1) Performed a single bout of unaccustomed lower body resistance exercise
(2) Immediately followed by a noncaloric placebo beverage or supplement containing 10, 20, 30, 40 g of whey protein concentrate (WPC)
(1) Resistance exercise alone reduced intramuscular branch chain amino acid (BCAA; leucine, isoleucine, and valine) content
(2) Supplementation with increasing doses of whey protein prevented this fall in muscle BCAAs during postexercise recovery
(3) Larger doses (30 g and 40 g) significantly augmented postexercise muscle BCAA content above that observed following placebo
– Intramuscular BCAAs, and leucine in particular, appear to be important regulators of anabolic signaling in aged human muscle during postexercise recovery via reversal of exercise-induced declines in intramuscular BCAAs
Michelle M Farnfield, Leigh Breen, Kate A Carey, Andrew Garnham, David Cameron-Smith
(1) 16 healthy young (aged 18-25 years) and 15 healthy older men (aged 60-75 years) completed 12 weeks of resistance exercise
(2) And were randomly assigned to consume a whey protein (WPI) or placebo drink after each session
(1) All subjects significantly increased strength after following strength training
(2) Phosphorylation of mTOR was significantly greater in the WPI groups compared with placebo for both younger and older subjects
(3) Phosphorylation of p70(S6K), eIF4G, and 4EBP1 was greater for older subjects consuming WPI
(4) Phosphorylation of rpS6, eIF4G, and 4EBP1 tended to increase in the younger subjects that had consumed WPI
(5) Post-training, younger subjects demonstrated a similar pattern of mTOR phosphorylation as seen pre-training.
(6) In contrast, the initial heightened phosphorylation of mTOR, p70(S6K), rpS6, and eIF4G in older muscle to combined resistance exercise and WPI ingestion became less pronounced after repeated training sessions
(7) In the untrained state, resistance exercise coupled with WPI increases phosphorylation of proteins involved in mRNA translation compared with exercise alone
(8) Post-training, WPI- and exercise-induced protein phosphorylation was reduced in older men, but not in younger men.
– Strategies to induce hypertrophy should utilize protein and resistance training concurrently.