INFLUENCE OF DIFFERING MACRONUTRIENT INTAKES ON MUSCLE GLYCOGEN RESYNTHESIS AFTER RESISTANCE EXERCISE

The provision of additional protein (Pro) to a carbohydrate (CHO) supp lement resulted in an enhanced rate of muscle glycogen resynthesis aft er endurance exercise (Zawadzki et al., J. Appl. Physiol. 72: 1854-185 9, 1992). A comparison of isoenergetic CHO and CHO/Pro formula drinks on muscle glycogen resynthesis has not been examined after either endu rance or resistance exercise. We studied the effect of isoenergetic CH O (1 g/kg) and CHO/Pro/fat (66% CHO, 23% Pro. 11% fat) defined formula drinks and placebo (Pi) given immediately (t = 0 h) and 1 h(t = +1 h) after resistance exercise in 10 healthy young men. They performed a w hole body workout (9 exercises/3 sets at 80% 1 repetition maximum) wit h unilateral knee extension exercise [exercise (Ex) and control (Con) leg]. The CHO/Pro/fat and CHO trials resulted in significantly greater (P < 0.05) plasma insulin and glucose concentration compared with Pl. Muscle glycogen was significantly lower (P < 0.05) for the Ex vs. Con leg immediately postexercise for all three conditions. The rate of gl ycogen resynthesis was significantly greater (P < 0.05) for both CHO/P ro/fat and CHO (23.0 +/- 4.5 and 19.3 +/- 6.1 mmol.kg dry muscle(-1).h (-1), respectively) vs. Pl (Ex = 2.8 +/- 2.3 and Con = 1.4 +/- 3.6 mmo l.kg dry muscle(-1)h(-1)). These results demonstrated that a bout of r esistance exercise resulted in a significant decrease in muscle glycog en and that consumption of an isoenergetic CHO or CHO/Pro/fat formula drink resulted in similar rates of muscle glycogen resynthesis after r esistance exercise. This suggests that total energy content and CHO co ntent are important in the resynthesis of muscle glycogen.