A comparison of workload quantification methods in relation to physiological responses to resistance exercise.

The purpose of this study was to (a) assess the usefulness of volume load (VL), session rate of perceived exertion (SRPE), RPE load (RPEL), and a modified RPEL (RPEL-2) to estimate internal load from resistance exercise (RE) and (b) further assess the interactions between SRPE, VL, and RE intensity. Twelve healthy men (25 ± 4 years) completed RE sessions at 55, 70, and 85 1 repetition maximum (1RM). Volume load, SRPE, RPEL, and RPEL-2 for each session were calculated, compared, and correlated with change values (Δ) for blood lactate and salivary cortisol. There were substantial increases in all measures of training load with progressive decreases in %1RM. There were clear substantial increases in Δ lactate and Δ cortisol after RE at 55% 1RM when compared with 70 and 85%. Within-subject correlations with Δ cortisol were small with SRPE (r = 0.25; 90% confidence limits; ±0.32), RPEL (r = 0.23; ±0.32), RPEL-2 (r = 0.19; ±0.32), and trivial for VL (r = 0.01; ±0.28). Correlations with Δ lactate were moderate with VL (r = 0.42; ±0.29) and RPEL-2 (r = 0.38; ±0.29), and small with SRPE (r = 0.25; ±0.32) and RPEL (r = 0.25; ±0.32). Correlation between SRPE and VL was large (r = 0.55; ±0.25). Although Δ lactate and Δ cortisol did not follow the same trends as measures of workload, VL may be superior to estimate internal load from RE, particularly when measured through Δ lactate. When viewing training load globally, RPEL-2 may offer the greatest advantage. Finally, our results suggest that SRPE seems to be more closely related to VL than %1RM.