An effective high-intensity intermittent exercise protocol for decreasing skeletal muscle glycogen

Abstract

The decrease of muscle glycogen may be useful for the improvement of endurance performance. Intense anaerobic exercise requires a high rate of glycogen utilization, but consecutive intense anaerobic exercises induce a pronounced decline of external power and muscle glycogen consumption. We hypothesized that a long rest period between consecutive intense anaerobic exercises may aid in sustaining external power and glycogen consumption. Secondly, we hypothesized that active rest (AR) during the long resting period may be more effective than passive rest (PR). Six subjects performed four 30-second Wingate tests (WAnT) with a 4-minute recovery between each bout (Consecutive method). The subjects also performed a similar exercise procedure, but with a 30-minute seated resting period after the second bout (PR method). The other six male subjects performed four 30-second WAnTs with a 4-minute recovery between each bout, with 30-minutes of cycling at 40% V O2max after the second bout (AR method). The subjects also performed PR method. The total work during the third and fourth bouts was greatest under the AR condition, followed by the PR condition, and finally the Consecutive method (p<0.05 for all comparisons). Blood lactate concentration during resting period was significantly lower, while muscle glycogen consumption was greater AR method than PR method (p<0.05 for both). A long resting period between consecutive intense anaerobic exercises may prevent the decline in external power and work. Additionally, AR has more favorable effects on muscle glycogen consumption, resulting in very low muscle glycogen levels, even with a small total amount of exercise.