Carbohydrate Loading as a Means of Extending Endurance Performance

摘要

A carbohydrate (CHO) loading program was tested in 9 Naval Special Warfare personnel to determine whether or not such a program could increase their endurance performance. Participants were divided into two groups. Each participant was given 2 treatments: a 6-day CHO loading diet-exercise program and a 6-day nonloading program. A counterbalanced design was used with each participant serving as his own control. For each treatment, the participants ate a combination of liquid formula diet and solid food providing 3500 cal/day. The loading program consisted of 3 days of 3% CHO diet, followed by 2 days of 64% CHO diet, followed by 1 day of 46% CHO diet. Concurrently, a daily running schedule of 14 miles, 6 miles, 4 miles, 1 mile, 1 mile, and 0 miles was followed for days 1-6 respectively. The nonload program consisted of 6 days of 46% CHO diet and daily runs of 4 miles for days 1-5 and 0 miles for day 6. Endurance performance was determined on day 7 with the participants running on a motor-driven treadmill at 0% grade, at the speed necessary to attain approximately 80% of participants' VO2 max. Performance was measured as the period of time a person could run before reaching subjective exhaustion. VO2, heart rate, and rectal temperature were monitored during the run. We found that the mean running time was greater by 10.8 minutes following the loading program vs. the nonloading program. This difference represents a 9.0% increase in running time and is significant.