Olson, E. C., Christensen, K. V., Jajtner, A., Copeland, J., Unthank, M., & Mitchell, J. B. (2012). The effect of short and long recovery periods on the contribution of oxidative processes to energy expenditure during multiple bouts of supramaximal exercise. Presentation 1336 at the 59th Annual Meeting of the American College of Sports Medicine, San Francisco, California; May 29-June 2, 2012.

This study examined the effect of short- and long-active recovery durations on oxidative and anaerobic energy contributions during maximal-intensity cycle ergometry. Males (N = 6) completed a maximum oxygen uptake (VO2max) test on a bicycle ergometer after which each S completed two treatments: a short-recovery condition and a long-recovery condition. The short-recovery condition consisted of 10, 10-second supramaximal sprints with 30-second recovery periods. The long-recovery condition consisted of 10, 10-second supramaximal sprints with 3-minute recovery periods. The load applied to the ergometer was 1.2 g/kg and the RPM during the sprints varied based on the maximal output. During recovery, no load was applied and Ss maintained a cadence of 80 RPM. Oxygen uptake (VO2) was measured throughout both conditions and peak power and total work were calculated from two, 5-second RPM averages generated during the sprints. Blood samples were taken pre-exercise, after sprints 4, 7, and 10, and three minutes post-exercise.

Peak power and total work were significantly greater in the long-recovery condition compared to the short-recovery condition. Peak power decayed by 21.7% over the 10 sprints in the short-recovery condition but there was no decay in the long-recovery condition. Oxygen uptake averaged 28.3 + 0.9 ml/kg/min for the entirety of the long-recovery condition; whereas, in the short-recovery condition there was a large increase in oxygen uptake during the second sprint that remained elevated and averaged 47 + 1.5 ml/kg/min for the remaining sprints. There was no difference in blood lactate between conditions.

Implication. After repeated bouts of explosive exercise with short rest periods, oxidative processes play a more important role in energy production, most likely due to fatigue occurring in the anaerobic energy producing systems. High-intensity short-duration work bouts with short rest periods is a viable format for enhancing aerobic capacity. When rest periods are long, aerobic stimulation is decreased.

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