Influence of differing macronutrient intakes on muscle glycogen resynthesis after resistance exercise

The provision of additional protein (Pro)to a carbohydrate (CHO) supplement resulted in an enhanced rate ofmuscle glycogen resynthesis after endurance exercise (Zawadzki et al.,J. Appl. Physiol. 72: 1854-1859,1992). A comparison of isoenergetic CHO and CHO/Pro formula drinks onmuscle glycogen resynthesis has not been examined after eitherendurance or resistance exercise. We studied the effect of isoenergeticCHO (1 g/kg) and CHO/Pro/fat (66% CHO, 23% Pro, 11% fat) definedformula drinks and placebo (Pl) given immediately(t = 0 h) and 1 h(t = +1 h) after resistance exercisein 10 healthy young men. They performed a whole body workout (9 exercises/3 sets at 80% 1 repetition maximum) with unilateral kneeextension exercise [exercise (Ex) and control (Con) leg].The CHO/Pro/fat and CHO trials resulted in significantly greater(P < 0.05) plasma insulin andglucose concentration compared with Pl. Muscle glycogen wassignificantly lower (P < 0.05) for the Ex vs. Con leg immediately postexercise for all three conditions. The rate of glycogen resynthesis was significantly greater(P < 0.05) for both CHO/Pro/fat andCHO (23.0 ± 4.5 and 19.3 ± 6.1 mmol · kg drymuscle¹ · h¹,respectively) vs. Pl (Ex = 2.8 ± 2.3 and Con = 1.4 ± 3.6 mmol · kg drymuscle¹ · h¹).These results demonstrated that a bout of resistance exercise resultedin a significant decrease in muscle glycogen and that consumption of anisoenergetic CHO or CHO/Pro/fat formula drink resulted in similar ratesof muscle glycogen resynthesis after resistance exercise. This suggeststhat total energy content and CHO content are important in theresynthesis of muscle glycogen.