Comparison of emg methods to identify aerobic and anaerobic thresholds in speed skaters

This study aimed to determine the breakpoints in superficial electromyography (sEMG) signal during a maximal incremental skating test (IT) and compare them to the first (VT1) and second (VT2) ventilatory threshold. Ten well-trained long track speed skaters performed a maximal incremental skating test on a slide board. sEMG signals from six lower limb muscles were recorded for the last 15 s of each stage and converted to root mean square (RMS) for determination of breakpoints in linearity using both mathematical (2 and 3 linear regressions) and visual methods. All three forms of breakpoints detection were correlated with the VT2. The combined quadriceps (vastus lateralis and medialis) and gluteus (gluteus maximus+ gluteus medius) showed higher breakpoint detection rate and higher correlations with VT2. The 2 lines mathematically detected breakpoints displayed higher validity indices to VT2, while the visually determined breakpoints were significantly higher than VT2.