Figure 1. Experimental setup, (a) sEMG electrode placement and identification of the recorded muscles. (b) Definition of phases of kicking legs. (c) Workflow of wavelet transformation. The EMG signals were bandpass filtered. The 11 non-linearly scaled Morlet wavelets were used for the wavelet transformation. EMG signal was transformed in time-frequency domain. (d) Time-domain feature extraction using principal component analysis (PCA).