Hendelman, D. L., Ornstein, K., Volpe, S., & Freedson, P. S. (1997). Pre-exercise carbohydrate feeding in adolescent boys: Effect on exercise responses and performance. Medicine and Science in Sports and Exercise, 29(5), Supplement abstract 724.

This study investigated the effects of pre-exercise carbohydrate feeding on responses to endurance exercise and performance in untrained high school boys (N = 13).

Ss were exposed to three endurance test sessions consisting of 75 min of cycling at 60% VO2max followed by a high intensity performance test. The performance test involved cycling 2500 m as fast as possible against a resistance of 5% body weight. Dietary treatments were a candy bar (280 kcal, 35 gm CHO), fat free fig bars (200 kcal, 42 gm CHO), and a non-nutritive sweetened drink (placebo) ingested 10 min before exercise.

Results showed no differences among the conditions for VO2, heart rate, RER, glucose, or lactate with significant time effects on all variables, that is, the variables changed as the task progressed. Performance times on the all-out test were not different.

Pre-exercise feeding did not affect the responses to endurance exercise of untrained adolescent boys.

Implication. A feeding of CHO very close to the commencement of an endurance exercise bout does not affect the endurance performance of untrained adolescent boys. It would be interesting to see what happens with trained boys.

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