Reproducibility of blood lactate-anchored ratings of perceived exertion

Abstract.

This study investigated the reproducibility of blood lactate-anchored ratings of perceived exertion (RPE) in seven women of average, and seven of above average cardiorespiratory fitness, [moderate and high maximal oxygen uptake (Mod $\dot V{\rm O}_{{\rm 2max}}$ and High $\dot V{\rm O}_{{\rm 2max}}$ , respectively)]. The subjects completed a series of four exercise tests, comprising a $\dot V{\rm O}_{{\rm 2max}}$ assessment and three 0-grade, velocity-incremental, treadmill-running RPE estimation trials. The results revealed no significant between-group differences in RPE at the blood lactate concentration threshold (LT), and at reference levels of 2 , 2.5 or 4 mmol·l^–1 (RPE_LT, RPE₂, RPE_2.5 and RPE₄, respectively). The RPE_LT, RPE₂, RPE_2.5 and RPE₄ were characterised by intra-class correlation coefficients of 0.97, 0.97, 0.97, 0.72 and 0.83, 0.96, 0.96, 0.90, in the High $\dot V{\rm O}_{{\rm 2max}}$ and Mod $\dot V{\rm O}_{{\rm 2max}}$ groups, respectively. The SEM% (95% confidence limits computed as a percentage of the group mean score) largely mirrored the trend in reliability with the highest values observed for RPE_LT in the Mod $\dot V{\rm O}_{{\rm 2max}}$ group and RPE₄ in the High $\dot V{\rm O}_{{\rm 2max}}$ group. The Spearman-Brown prediction equation indicated that fixed blood lactate concentrations of 2, 2.5 and 4 mmol·l^–1 offer acceptable practical utility as potential perceptual anchor points for both groups, requiring one trial only to achieve a measurement error of less than ±6%.