Fixed Versus Self-Selected Rest Durations During Repeated High-Intensity Cycling: Effects on Performance and Sex-Specific Rest Strategies

This article compares the effects of fixed and self-selected (SS) rest durations on repeated high-intensity cycling performance, perceptual responses, and rest allocation in male and female varsity athletes. Twenty-seven varsity athletes (17F) completed two randomized sessions of 9 × 30 s high-intensity cycling bouts. Rest duration was fixed at 90 s, or SS, with total rest time constrained to 12 min in both sessions. Generalized estimating equations assessed session, sex, and bout on power output, rest, and perceptual outcomes. Pearson correlations examined associations between rest allocation and performance. Total power was higher in the SS session (+42.7 W, p = .02, g = 0.21). SS rest (+57s, p < .001) and perceived exertion increased (+3.79, p < .001) by bout, but no session differences were observed for exertion, fatigue, or enjoyment (p > .05). Perceived autonomy scores were higher in the SS session (+1.30, p < .001, g = 1.33). Exploratory analyses indicated that females adopted longer rest durations than males in later bouts (p = .01), although no sex-by-session interaction was observed for performance. No associations were observed between SS rest duration variability and performance (r = 0.02, p = .78). Self-selected rest produced small but statistically detectable increases in total power output and substantially increased perceived autonomy without altering other perceptual responses. These findings suggest that SS rest may provide a flexible alternative to fixed HIIT prescriptions in varsity athletes, though the magnitude of performance enhancement was modest and warrants replication in sport-specific contexts.