Effect of post-exercise supplement consumption on adaptations to resistance training.
OBJECTIVE
Athletes are interested in nutritional manipulations that may enhance lean tissue gains stimulated by resistance training. Some research demonstrates that acute consumption of food containing protein causes superior muscle protein synthesis compared to isoenergetic foods without protein. This benefit has not been verified in longer-term training studies. We compared body composition and muscle function responses to resistance training in males who consumed a carbohydrate or a multi-macronutrient beverage following each training session.


METHODS
Nineteen, untrained men (18-25 years) consumed either a milk (MILK) or a carbohydrate-electrolyte (CHO) drink immediately following each workout during a 10 week resistance training program. Muscle strength (1RM for seven exercises), body composition (DXA scan), fasted, resting concentrations of serum total and free testosterone, cortisol, IGF-1, and resting energy expenditure (REE) were measured prior to and at the end of training.


RESULTS
Resistance training caused an increase (44 +/- 4%, p < 0.001) in muscular strength for all subjects. The training program reduced percent body fat (8%, p < 0.05, -0.9 +/- 0.5 kg) and increased fat-free soft tissue (FFST) mass (2%, 1.2 +/- 0.3 kg, p < 0.01). MILK tended to increase body weight and FFST mass (p = 0.10 and p = 0.13, respectively) compared to CHO. Resting total and free testosterone concentrations decreased from baseline values in all subjects (16.7%, 11%, respectively, p < 0.05). Significant changes in fasting IGF-1, cortisol, and REE across training were not observed for either group.


CONCLUSIONS
Post-resistance exercise consumption of MILK and CHO caused similar adaptations to resistance training. It is possible that a more prolonged training with supplementation period would expand the trend for greater FFST gains in MILK.
Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg VA 24061-0430, USA. jrankin@vt.edu
Janet Walberg
JW
Rankin
Lauren P
LP
Goldman
Michael J
MJ
Puglisi
Sharon M
SM
Nickols-Richardson
Carrie P
CP
Earthman
Frank C
FC
Gwazdauskas
D000222:Adaptation, Physiological / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D000818:Animals; D001481:Basal Metabolism / Q000502:physiology; D001628:Beverages; D001823:Body Composition / Q000502:physiology*; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D019587:Dietary Supplements; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008297:Male; D008892:Milk; D018482:Muscle, Skeletal / Q000502:physiology*; D013739:Testosterone / Q000097:blood; D014891:Weight Lifting / Q000502:physiology*
D004040:Dietary Carbohydrates; D013739:Testosterone; D007334:Insulin-Like Growth Factor I; D006854:Hydrocortisone