V˙O2max assessment in athletes: A thorough method comparison study between Yo-Yo test and direct measurement

Introduction

Although different studies have reported limits of agreement in assessing $\dot{\text{V}}{\text{O}}_{2\max }$ between the Yo-Yo test and the direct measurement, the precision of these limits in general has not been considered. The aim of this study was to examine the extent of agreement in the assessment of $\dot{\text{V}}{\text{O}}_{2\max }$ in athletes between the Yo-Yo endurance test (YET) and the direct measurement (DM), and to quantify the precision of the estimated limits of agreement.

Material and methods

Data were obtained from a group of 11 male field hockey players (Age = 22.2 ± 3.6 yrs, BMI = 22.1 ± 2.4 kg m⁻²). DM was performed using an incremental treadmill running test. YET level 1 was used for indirect estimation of $\dot{\text{V}}{\text{O}}_{2\max }$. Bland–Altman analysis was employed for assessing agreement between the two methods. The acceptable 95% limits of agreement were set a priori at ±5 ml kg⁻¹ min⁻¹.

Results

A non-statistically significant bias was observed between YET and DM (50.78 vs. 51.09 ml kg⁻¹ min⁻¹, P > .05). The estimates of the 95% limits of agreement were −4.34 and 3.72 ml kg⁻¹ min⁻¹. And the 95% confidence intervals for these limits were from −6.78 to −1.90 ml kg⁻¹ min⁻¹, and from 1.29 to 6.16 ml kg⁻¹ min⁻¹, respectively. The difference between methods did not appear to be correlated to the magnitude of measurement.

Conclusions

A reasonably good agreement was found between YET and DM. However, the large variance of the limits of agreement due to the small sample size means these results should be treated with caution.