To investigate the effect of measurement timing and concurrent validity of session (sRPE) and differential (dRPE) ratings of perceived exertion as measures of internal training load (ITL) in adolescent distance runners.
Fifteen adolescent distance runners (15.2 ± 1.6 y) performed a two-step incremental treadmill test for the assessment of maximal oxygen uptake, heart rate and the blood lactate responses. Participants were familiarised with RPE and dRPE during the treadmill test using Foster's modified CR-10 Borg scale. Subsequently, each participant completed a regular two-week mesocycle of training. Participants wore a heart rate monitor for each exercise session and recorded their training in a logbook, including sRPE, dRPE leg exertion (dRPE-L) and breathlessness (dRPE-B) following session completion (0 min), 15 min post-session and 30 min post-session.
sRPE, dRPE-L and dRPE-B scores were all most likely lower when reported 30 min post-session, compared to scores 0 min post-session (% change ±90% confidence limits; sRPE, -26.5% ±5.5%; dRPE-L, -20.5% ±5.6%, dRPE-B, -38.9% ±7.4%). sRPE, dRPE-L and dRPE-B all maintained their largest correlations (r = 0.74 to 0.89) when reported at session completion (0 min), in comparison to each of the HR-based criteria measures.
sRPE, whether reported 0 min, 15 min or 30 min post-session, provides a valid measure of ITL in adolescent distance runners. Also, dRPE-L and dRPE-B can be used in conjunction with sRPE, across all time-points (0, 15 and 30 min), in order to discriminate between central and peripheral exertion.