Effect of exercise duration on session RPE at an individualized constant workload

Session RPE (SRPE) permits subjective ratings of global effort following exercise. SRPE is useful for evaluating training load; however, mediating factors are not well understood. This study compared SRPE among treadmill trials at a clamped workload with a varied duration. Ten subjects (VO₂max: 48.9 ± 10.5 ml kg⁻¹ min⁻¹) completed a maximal-exertion treadmill trial followed by treadmill trials of 20 (TM20), 30-(TM30), and 40-(TM40) min (counterbalanced) duration at approximately 70% individualized VO₂max. Heart rate (HR) and acute RPE (during exercise) were recorded every 5 min with blood lactate concentration [La] recorded before initiating exercise and every 10 min throughout exercise to completion. Analyses showed no significant differences among TM20, TM30, and TM40 for mean HR, [La] or acute RPE which isolated effects of duration on SRPE. Session RPE (recorded 20 min post exercise) relative to overall (SRPEO), legs (SRPEL) and breathing (SRPEB) was analyzed using a 3 (trial) × 3 (SRPE: O, L, B) repeated measures ANOVA (alpha 0.05). There was no main effect for duration, but there was a significant main effect for SRPE type with SRPEO (4.40 ± 2.18) greater than SRPEB (3.56 ± 1.98) but no difference for SRPEL (4.43 ± 2.16). Follow-up tests for within-trial differences showed no significant differences for SRPEL versus SRPEO, but blunted SRPEB estimations (vs. SRPEO and SRPEL). Primary results indicate affects of duration on SRPE are minimal. Further, within the limits of the current study, differentiating SRPE estimations do not appear advantageous; however, further work is warranted.