Is glucose/amino acid supplementation after exercise an aid to strength training?

Background-The precise timing of carbohydrate and amino acid ingestion rela tive to a bout of resistance exercise may modulate the training effect of t he resistance exercise. Objective-To assess whether regular glucose/amino acid supplementation imme diately after resistance exercise could enhance the gain in muscle strength brought about by resistance training. Methods-Seven untrained participants with a median age of 23 years and mean (SD) body mass 68.9 (13.5) kg resistance trained on a leg extension machin e for five days a week for 10 weeks, using four sets of 10 repetitions. Alt ernate legs were trained on successive days, one leg each day. Subjects ing ested either a supplement including 0.8 g glucose/kg and 0.2 g amino acids/ kg, or placebo, on alternate training days immediately after training. Ther efore the supplement was always ingested after training the same leg (suppl ement leg). Isometric, isokinetic, and 1 repetition maximum (RM) strength w ere measured before, during, and after training. Blood samples were analyse d to determine the acute responses of insulin and glucose to resistance exe rcise and supplementation or placebo. Results-Serum insulin concentration peaked 20 minutes after supplement inge stion at ninefold the placebo level, and remained significantly elevated fo r at least 80 minutes (p<0.01). Isometric, isokinetic, and 1 RM strength im proved on both supplement and placebo legs (p<0.05). There were no signific ant differences in the gain in strength between the supplement leg and the placebo leg (p>0.05). Conclusion-Regular glucose/amino acid supplementation immediately after res istance exercise is unlikely to enhance the gain in muscle strength brought about by resistance training.