How is rating of perceived capacity related to VO(2max) and what is VO(2max) at onset of training?

OBJECTIVE: To evaluate how rating of perceived capacity (RPC) is related to maximal oxygen uptake (VO(2max)) and examine VO(2max) at onset of training in healthy adults. METHODS: In total, 125 newly registered fitness centre members, equally men and women, answered the RPC scale and performed a treadmill test for measurement of VO(2max). Eligible criteria were <4 weeks of fitness centre membership, physically inactive, ≥18 years and not pregnant. The RPC is a one-page scale (1–20) based on metabolic equivalent tasks, where the individual chooses the most strenuous activity that can be sustained for at least 30 min. RESULTS: The Bland-Altman plot demonstrated a tendency of overestimation, meaning that the participants ranked their own aerobic capacity 17.5% higher than objectively measured values of VO(2max). The mean difference between the two methods were +4.92±1.96 and +6.35±1.96 mL/min/kg VO(2) in men and women, respectively. The Pearson correlation coefficient was moderate, with r=0.426 (p<0.01). A linear regression analysis showed that both age and VO(2max) were significant predictors of RPC (p<0.01). Measured VO(2max) at onset of fitness centre membership was in men aged 38.7±11.7 and women aged 34.7±9.9, 40.5±7.2 and 35.0±6.0 mL/min/kg, respectively. Estimated VO(2max) from the RPC scale was 45.7±9.8 and 41.4±10.1 mL/min/kg in men and women, respectively. CONCLUSIONS: The RPC seems less accurate at the individual level and may overestimate VO(2max). Still, it may be considered useful in large-scale studies.