The Effects of Exercise Modality on Pacing Strategy During Endurance Exercise

Adjustments in power output and physical effort during maximal exercise are observed in both untrained individuals and elite athletes. The resulting pacing strategy (PS) enables athletes to obtain a level of optimal performance while limiting physical harm. PS is modified by environmental and physiological factors, though the effects of exercise mode on PS modification remain poorly understood. PURPOSE: The aim of this study was to investigate the effect of exercise mode on PS during two time trials of similar intensity and duration. METHODS: 10 physically active men (23.00 ± 2.71 yrs, 175.00 ± 9.12 cm, 82.17 ± 19.50 kg) completed a baseline familiarization session and two experimental exercise sessions performed in a counterbalanced order. The experimental sessions included a 5 min warm-up and a 7 min time trial on either a cycle (Velotron, CompuTrainer Inc., Seattle, WA) or rowing ergometer (Concept II, Morrisville, VT). Prior to each time trial, subjects were instructed to complete as much distance as possible within the 7 min period, but were not provided with physiological feedback or verbal encouragement. Average power output was determined at the end of each minute of exercise to compute relative power output in order to analyze PS. Heart rate (HR), rating of perceived exertion (RPE), and blood lactate (BL) were collected throughout both time trials to document homeostatic disturbance caused by exercise. RESULTS: Repeated measures ANOVA (mode x time) were used to statistically analyze relative power output (2 x 6), HR (2 x 6), RPE (2 x 3), and BL (2 x 2). No significant interaction or main effect for mode was found for relative power output (p < .05). There was a main effect for time (p < .001), with a higher relative power output occurring at min 7 of exercise compared to all other minutes of the time trial. HR, RPE, and BL were not significantly different between modes (p > .05). There was a main effect for time for HR, RPE, and BL (p = .00), each of which increased at each successive time point. CONCLUSION: Exercise mode did not contribute to significant differences in PS during maximal endurance tasks of similar intensity and duration. The similarity in PS utilized and in the levels of homeostatic disturbance achieved supports the idea of an individual critical threshold that regulates effort during maximal endurance exercise.