The validity and reliability of predicting maximal oxygen uptake from a treadmill-based sub-maximal perceptually regulated exercise test.

The purpose of this study was to determine for the first time whether VO2max could be predicted accurately and reliably from a treadmill-based perceptually regulated exercise test (PRET) incorporating a safer and more practical upper limit of RPE 15 ("Hard") than used in previous investigations. Eighteen volunteers (21.7 +/- 2.8 years) completed three treadmill PRETs (each separated by 48 h) and one maximal graded exercise test. Participants self-regulated their exercise at RPE levels 9, 11, 13 and 15 in a continuous and incremental fashion. Oxygen uptake VO2 was recorded continuously during each 3 min bout. VO2 values for the RPE range 9-15 were extrapolated to RPE(19) and RPE(20) using regression analysis to predict individual VO2max scores. The optimal limits of agreement (LoA) between actual (48.0 +/- 6.2 ml kg(-1) min(-1)) and predicted scores were -0.6 +/- 7.1 and -2.5 +/- 9.4 ml kg(-1) min(-1) for the RPE(20) and RPE(19) models, respectively. Reliability analysis for the VO2max predictions yielded LoAs of 1.6 +/- 8.5 (RPE(20)) and 2.7 +/- 9.4 (RPE(19)) ml kg(-1) min(-1) between trials 2 and 3. These findings demonstrate that (with practice) a novel treadmill-based PRET can yield predictions of VO2max that are acceptably reliable and valid amongst young, healthy, and active adults.