EMG signal spectral analysis of superficial quadriceps muscles during constant load submaximal cycling exercise - doi: 10.4025/reveducfis.v22i2.9734

Abstract

The objective of this study was to investigate possible differences in the EMG signal spectral analysis of the superficial quadriceps muscles, using the techniques short-time Fourier transform (STFT) and continues Wavelet (CWT) db4 type during constant load submaximal cycling exercise. Fourteen male subjects, healthy and physically active (25.8 ± 3.3 years, 82.1 ± 7.3 kg, 181.3 ± 5.5 cm) were submitted to constant load submaximal test (Tcons) with exercise intensity corresponding to 80% of maximum load until voluntary exhaustion. The EMG of the vastus lateralis (VL), vastus medialis (VM) and rectus femoris (RF) of the right leg were recorded throughout the period of the Tcons to obtain the parameters: median frequency (MF), fatigue index EMG (FIslp) and variance of MF. The results showed no statistically significant differences for the variables MF, FIslp and variance of MF in any of the muscles examined in different time periods, when comparing STFT and CWT (P> 0.05). Thus, our findings suggest the use of both analytical techniques in constant load submaximal cycling exercise when the target is to quantify muscle fatigue with EMG spectral indicators.