Direct Versus Indirect Submaximal VO₂max Assessment in Masters Basketball Players

Background: Accurate assessment of aerobic capacity is essential for performance monitoring in masters athletes, particularly in high-intensity team sports. The objective of this study was to evaluate the validity and agreement of three indirect maximal oxygen uptake (VO₂max) protocols (Åstrand-Ryhming, YMCA, and Polar OwnIndex Fitness test) against the gold-standard cardiopulmonary exercise testing (CPET) in masters basketball players. Methods: A cross-sectional comparative study included 50 male masters basketball players (aged 51-81 years, M = 64.3 ± 7.9). Validity was determined by comparing results from the three indirect protocols to direct VO₂max measurement via CPET. Agreement was assessed using Pearson correlations (r), systematic error, mean absolute error (MAE), and Bland-Altman limits of agreement. Results: The Åstrand-Ryhming test and YMCA tests showed the closest agreement with CPET (systematic error < 4%, MAE ≈ 17-18%, r > 0.50). The Polar OwnIndex test substantially overestimated VO₂max (mean error ≈ 30%, MAE = 32%). The Åstrand-Ryhming test at low workload yielded the strongest correlation (r = 0.75). Conclusions: The Åstrand-Ryhming and YMCA submaximal tests demonstrated acceptable validity and low systematic bias for estimating VO₂max in masters basketball players, positioning them as practical alternatives to CPET. Conversely, the Polar OwnIndex test showed poor agreement and clinically significant overestimation. These findings support the use of submaximal cycling protocols for fitness monitoring and tailored training prescription in this specific older athlete population. Future longitudinal research is warranted to confirm their ability to track fitness changes over time in this population.