Effects of post-exercise carbohydrate-protein feedings on muscle glycogen restoration
The purpose of this investigation was to determine the effects of post-exercise carbohydrate-protein feedings on muscle glycogen restoration following exhaustive cycle ergometer exercise. Seven male collegiate cyclist (age=25.6±3.3y, ht.=180.9±8.5cm, wt.=75.4±10.7kg, VO2max=4.20±0.4 1•miri 1) performed three trials, each separated by -lwk, 1) 100% (x-D glucose (CHO), 2) 70% carbohydrate-20% protein-10% fat (CHOPRO), and 3) 86% carbohdyrate-14% amino acid (CHO-AA). All feedings were eucaloric, based upon 1.0 g•kgb.W.'1•hr"1 of carbohydrate, and administered every half hour during a four hour muscle glycogen restoration period in an 18% wt./vol. solution. Muscle biopsies were obtained immediately and four hours post exercise. Following the exhaustive exercise and every half hour for four hours a blood sample was drawn. Muscle glycogen concentrations increased 53%, 47%, and 57% for the CHO, CHO-PRO, and CHO-AA feedings, respectively, however no differences among the feedings were apparent in muscle glycogen restoration. The plasma glucose and insulin concentrations demonstrated no differences throughout the restoration period among the three feedings. These results suggest that muscle glycogen restoration does not appear to be enhanced with the addition of either protein or amino acids to an eucaloric carbohydrate feeding following an exhaustive cycle exercise. However, it appears that if adequate amounts of carbohydrates are consumed (greater than 0.70 g•kgb,W,."'•hf' carbohydrate) following exhaustive exercise, maximal muscle glycogen restoration occurs.