V̇O2PEAK PROVIDES A BETTER PREDICTOR OF ERGOMETER MEAN MAXIMAL POWER THAN MAXIMAL OXYGEN EXTRACTION IN TRAINED ROWERS

Abstract

INTRODUCTION & AIMS Muscle oxygenation characteristics are suggested to better explain performance than peak oxygen uptake (V̇O2peak) in highly trained canoe-kayak athletes (Paquette et. al, 2018), but this has not been explored with rowers. Therefore, this investigation aimed to 1) determine whether maximal oxygen extraction improved prediction of rowing ergometer mean maximal power (MMP; W/kg) compared to V̇O2peak alone, and 2) assess differences in muscle oxygen extraction between anatomical sites during incremental rowing. METHODS Trained male (n=16) and female (n=6) rowers completed a 7x4min graded exercise test on a rowing ergometer to determine mean power output for each stage and V̇O2peak and MMP during the final stage. Change in muscle oxygen extraction (Δ[HHb]) during each stage was determined using near infrared spectroscopy (NIRS) at the vastus lateralis (VL), gastrocnemius medialis (GM), and biceps brachii (BB). The best predictor of MMP was determined using linear regression, and mixed-effects models were used to assess Δ[HHb] across sites and stage. RESULTS V̇O2peak was a significant predictor of MMP (R2=0.74); however, Δ[HHb] (at each site individually or combined) had no association with MMP (R2≤0.05). The strongest model included V̇O2peak and GM Δ[HHb] (R2=0.83); however, the improvement in model fit was modest (mean absolute error decreased from 0.211W.kg-1 to 0.193W.kg-1). A significant site x stage interaction was observed for Δ[HHb] at each site across all stages. Post-hoc analysis revealed VL Δ[HHb] was higher than GM Δ[HHb] for each stage; VL Δ[HHb] was lower than BB Δ[HHb] from stages 1-4, then higher from stages 5-7; and GM Δ[HHb] was lower than BB Δ[HHb] for stages 1-6, but higher in the final stage. CONCLUSION Maximal oxygen extraction alone cannot predict ergometer MMP in trained rowers. However, NIRS derived muscle oxygen extraction may provide additional useful information regarding relative muscle contributions at varying exercise intensities.