The effects of carbohydrate feedings on glycogen synthesis after aerobic and anaerobic cycle exercise

The importance of muscle glycogen as a fuel source during exercise has been well documented. Maintaining a high glycogen level before and during activity is a major determinant of performance. Elevation of glycogen levels during recovery from both aerobic and anaerobic bouts of exercise is critical. The purpose of this investigation was to determine the effect of a solid carbohydrate feeding on glycogen resynthesis following aerobic and anaerobic exercise. Eight male cyclists were recruited for this investigation. One hour ride trial, 70 % VO2max followed with feeding (HRY), one sprint trial followed with feeding (SPY), and one sprint trial followed with no feeding (SPN) were randomly performed and separated by ten days. Feeding trials consisted of a solid CHO source (1g CHO per kg bw per hr) fed for four hours of recovery following one hour of passive recovery with no food. Muscle biopsies were obtained immediate post and at six hours of recovery. Bloods were collected at 1, 4, and 30 minutes of recovery for lactate determination. Muscle specimens were analyzed for glycogen and lactate. Muscle glycogen (mmol • kg protein') levels post exercise for HRY, SPN, and SPY trial were 336.9±48.1, 481.0±47.0, and 417.5±26.4, respectively with HRY significantly lower than SPN. The increase in muscle glycogen six hours post-exercise for HRY, SPN, and SPY trials were 117.9±24.8, 29.5 ±22.2, and 207.2 ±20.4, respectively, which were all significantly different (P < 0.05). Blood lactate at + 1 minute for HRY, SPN, and SPY trials were 3.4±.5, 20.6±1.2, and 19.9±1.3 mM, respectively. These data suggest that an athlete training twice during the day with both anaerobic and aerobic components will have greater muscle glycogen available later in the day if anaerobic training is completed first in the day, providing adequate carbohydrate is consumed between bouts.School of Physical EducationThesis (M.S.