Predicting Maximal Oxygen Uptake Via a Perceptually Regulated Exercise Test (PRET)

Recent research has yielded encouraging, yet inconsistent findings concerning the validity and reliability of predicting maximal oxygen uptake (O2max) from a graded perceptually regulated exercise test (PRET). Accordingly, the purpose of the present study was to revisit the validity and reliability of this application of ratings of perceived exertion (RPE) using a modified PRET protocol. Twenty-three volunteers (mean age, 31 ± 9.9 years) completed four counter-balanced PRETs (involving two 2-minute and two 3-minute bouts administered over 9 days, each separated by 48 hours) on an electromagnetically braked cycle ergometer and one maximal graded exercise test. Participants self-regulated their exercise at RPE levels 9, 11, 13, 15 and 17 in a randomized order. Oxygen uptake (O2) was recorded continuously during each bout. The O2 values for the RPE ranges 9–17, 9–15 and 9–13 were extrapolated to RPE 20 using regression analysis to predict individual O2max scores. The concordance of the predicted and actual O2max scores and the trial-to-trial reliability of the predicted scores were analyzed using the limits of agreement (LoA) technique. The LoA between actual (41.5 ± 8.0 mL·kg−1·min−1) and predicted O2max scores for the RPE range 9–17 were −2.6 ± 10.1 and −1.3 ± 7.4 mL·kg−1·min−1 (2-minute bout) and −1.0 ± 9.2 and 0.2 ± 7.2 mL·kg−1·min−1 (3-minute bout) for trials 1 and 2, respectively. Reliability analysis yielded LoA of −1.3 ± 9.2 mL·kg−1·min−1 (2-minute bout) and −0.8 ± 5.7 mL·kg−1·min−1 (3-minute bout). The modified PRET provided acceptable and repeatable estimates of O2max, suggesting its application in environments where maximal tests are inappropriate, and is worthy of further investigation.