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 onday 1; the response was diminished ondays 2 and3. Glucose and insulin were significantly elevated by 30 min during supplementation and remained stable during placebo. Insulin-like growth factor-I was higher during supplementatiom on days 2 and3. 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.
- growth hormone
- insulin-like growth factor-I
- weight training
Address for reprint requests: W. J. Kraemer, Director, Human Performance Laboratory, Ball State University, Muncie, IN 47306. (E-mail:).
This study was supported in part by a grant from Twin Laboratories, Inc. (Ronkonoma, NY), and additional support was from the Robert F. and Sandra M. Leitzinger Research Fund in Sports Medicine at the Pennsylvania State University.
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- Copyright © 1998 the American Physiological Society