Muscle oxygenation kinetics during the single-leg heel rise test

The single-leg heel rise (SLHR) test is a simple and widely used tool for evaluating calf muscular endurance in sports and dance by counting heel rises to fatigue. This study explored the potential of muscle near-infrared spectroscopy (mNIRS) to provide physiological insights into local muscle oxygenation and fatigue during SLHR performance.

In this cross-sectional study, twenty-four sports science students (9 females, 15 males) completed the SLHR test, during which the number of repetitions, heel rise height, total work, and local muscle oxygen saturation (SmO2) kinetics were recorded.

The post-exercise muscle oxygen re-saturation rate (SmO2RR) showed a moderate positive correlation with SLHR repetitions of the dominant leg (r=0.50, P=0.016, R²=0.248) and a strong positive correlation with the non-dominant leg (r=0.69, P<0.001, R²=0.479). Moderate correlations were also observed between SmO2RR and the total positive work performed (dominant: r=0.48, P=0.020, R²=0.231; non-dominant: r=0.42, P=0.044, R²=0.179). In contrast, peak (SmO2peak) and minimum (SmO2min) oxygen saturation levels were not associated with the number of repetitions and total work performed (P>0.05).

These findings highlight the potential of SmO2RR as a physiological marker of muscular endurance during submaximal dynamic tasks like the SLHR test. Future research should explore different paces and time intervals to further establish mNIRS-based indicators of muscular fatigue and recovery during this submaximal dynamic assessment.