Physiological and neuromuscular responses of competitive cyclists during a simulated self-paced interval training session.

Responses of twelve competitive cyclists performing an interval training session, consisting of three successive 10-min self-paced exercise bouts separated by two 15-min active recovery periods, were studied. Power output (PO), heart rate, pedaling cadence, ventilatory variables, overall ratings of perceived exertion (RPE) and electromyographic (EMG) activity of the vastus lateralis, vastus medialis, biceps femoris and medial hamstrings were recorded during each exercise bout. Mean PO (p<0.05) decreased significantly across the self-paced bouts, while RPE (p<0.01) increased significantly. PO and EMG activity did not show significant changes between the 3rd and 9th minute of each self-paced bout. Every self-paced bout showed an oxygen uptake (VO(2)) slow component between the 3rd and 9th minute and there was no effect of bout order on the magnitude of the VO(2) slow component. This study reveals that during an interval training session, moderately trained competitive cyclists are able to repeat three 10-min self-paced exercise bouts with only a slight decrease in PO (approximately 3%) and by maintaining unchanged physiological and neuromuscular responses. Moreover, the VO(2) slow component during each exercise bout was not related to changes in muscle activity, as every exercise bout was performed at a muscular work steady state with a constant PO.