Nonexercise Estimation of V̇O₂peak Using Seismocardiography in Female Subelite and Male Elite Football Players

A novel method for estimating V̇O₂peak using seismocardiography (SCG eV̇O₂peak) at rest was developed some years ago, and this study investigates an updated version using data from a trained population. Forty five subelite female and Sixty seven elite male football players were tested and included in a cross-sectional accuracy comparison between SCG eV̇O₂peak and V̇O₂peak obtained from an incremental cardiopulmonary exercise test (CPET) performed on a treadmill. In addition, the ability of the method to detect changes over time was assessed by comparison of changes in V̇O₂peak over 3 months (female and male, n = 60), 6 months (female, n = 17), and 1 year (male, n = 18) for CPET and SCG, respectively. No difference and a fair agreement were found between combined sex cross-sectional SCG eV̇O₂peak and CPET V̇O₂peak (bias ± 95% CI: -1.0 ± 0.9 mL·min^-1·kg^-1 and limits of agreement [95%]: ± 9.1 mL·min^-1·kg^-1), with similar agreement between sexes. The standard error of estimation and mean absolute percentage error were 4.8 mL·min^-1·kg^-1 and 7.4%, respectively. V̇O₂peak was only increased over 6 months for females (CPET: 2.2 ± 1.1 mL·min^-1·kg^-1, SCG: 1.2 ± 1.1 mL·min^-1·kg^-1, and p < 0.05) with no difference between methods (p = 0.170). A correlation between ΔV̇O₂peak for CPET and SCG was found for 1-year analyses (male, R² = 0.62, and P < 0.05) but no other correlations were significant. The SCG method is accurate in estimating V̇O₂peak in both subelite and elite football players, with fair agreement and low estimation errors. The SCG method was able to detect an association of 1-year changes but not for changes over shorter times; however, these results require more investigation due to small sample sizes.