Significance of time to exhaustion during exercise at the velocity associated with$\dot VO_{2max}$

Abstract

In theory, time to exhaustion at the velocity associated with$\dot VO_{2max}$ (t _LIM atv $\dot VO_{2max}$) together with the anaerobic threshold (AT) should provide information about the anaerobic capacity of an individual. The primary purpose of this study was to test that hypothesis, using oxygen deficit as a criterion for anaerobic capacity. A second purpose was to identify factors that might explain the large inter-individual variability reported int _LIM atv $\dot VO_{2max}$. Subjects were 13 female track athletes who, performed incremental treadmill tests to determinev $\dot VO_{2max}$ and AT and constant velocity tests at$\dot VO_{2max}$ to determinet _LIM and oxygen deficit. Correlations between oxygen deficit andt _LIM atv $\dot VO_{2max}$ and [(t _LIM atv $\dot VO_{2max}$) · ($\dot VO_{2max}$ − AT)], a compound variable derived based on the critical power concept, were 0.51 (p < 0.05, one-tailed) and 0.67 (p < 0.01). To identify factors related to the inter-individual variability int _LIM atv $\dot VO_{2max}$, correlations betweent _LIM and AT, oxygen deficit, and [oxygen deficit/($\dot VO_{2max}$ − AT)] were calculated. Intra-individual differences in AT explained 44% of the variability int _LIM atv $\dot VO_{2max}$, oxygen deficit explained 26% of the variance, and the compound variable explained only 36%. It was concluded that (a) alone, or in combination with AT,t _LIM atv $\dot VO_{2max}$ cannot be used to estimate anaerobic capacity and (b) factors other than anaerobic capacity and AT contribute to the relatively large intra-individual variability int _LIM atv $\dot VO_{2max}$ (CV = 21%). Determinants oft _LIM atv $\dot VO_{2max}$ must be elucidated if this measure is to be of use to sport scientists.