Criteria and other methodological considerations in the evaluation of time at V.O2max

Aim. Many previous studies have examined the time limit at which an individual can maintain V.O2max (Tlim V.O2max) during high-intensity continuous and intermittent runs to exhaustion. The main purpose of the present study was to examine the effects of employing different criteria used in previous investigations during Tlim V.O2max evaluation.
Methods. Seven moderately trained competitive runners completed 2 running tests to exhaustion, during which metabolic data was obtained from breath-by-breath gas analysis. The 1st test was an incremental test to evaluate V.O2max and the minimal running velocity at which V.O2max was elicited (v V.O2max). The 2nd test was a continuous single velocity test at v V.O2max from which the time to attain V.O2max (TA V.O2max) and Tlim V.O2max were subsequently evaluated. Time at V.O2max was evaluated employing 6 specific criteria. Intra-individual differences in Tlim V.O2max values due to applying the different criteria were analysed using a one-way ANOVA, with significant differences between pairs identified using Tukey’s HSD posthoc test. Significance was set at p<0.05.
Results. A one-way ANOVA demonstrated that significant differences (F=4.03, p=0.005) existed between Tlim V.O2max values generated by employing the six different criteria.
Conclusion. The present study provides support that employing different criteria in the evaluation of Tlim V.O2max, such as those used in previous investigations, leads to significantly different Tlim V.O2max values. However, the practical implications of these measurement differences require further investigation.