The aims of this investigation were to evaluate the physiological responses to laboratory based stochastic exercise and to assess the effects of stochastic versus steady-state exercise on subsequent cycling time trial (TT) performance. Six competitive cyclists (peak power output (PPO) 432 ± 39 W (values are mean ± SD) undertook in a random order two 150-min paced rides that were either constant load (58% of PPO) or stochastic in nature (58± 12.2% of PPO). These rides were immediately followed by a 20-km TT performance on an air-braked ergometer. Mean heart rate (HR) responses throughout the 150-min paced rides and during the subsequent TT were not significantly different between trials. Yet, despite the similarities in HR, the mean time for the TT was significantly faster (26:32 ± 1:30 vs 28:08 ± 1:47 min, P < 0.05), and the mean power output was significantly greater (340.3 ± 44.2 vs 302.5 ± 42.3 W; 77.8± 10.2 vs 70.0 ± 9.8% of PPO, P < 0.05) following the steady-state ride. These results demonstrate that following 150 min of steady-state riding, subsequent 20 km TT performance was significantly improved when compared with 150 min of stochastic exercise.
School of Life Science, Kingston University, Kingston Upon Thames, Surrey, ENGLAND, and MRC/UCT Bioenergetics of Exercise Research Unit Department of Physiology, University of Cape Town Medical School, SOUTH AFRICA
Submitted for publication October 1995.
Accepted for publication April 1996.
Address for correspondence: Garry S. Palmer, School of Life Science, Kingston University, Kingston upon Thames, Surrey, KT1 2EE, England. E-mail:G.PALMER@KING.AC.UK.