The frequency analysis of electromyographical (EMG) signals is a common tool in many biomechanical applications, mostly done using the Fourier Transformation (FT). However, the FT assumes a stationary signal, which means that the temporal analysis of the signal's frequency content is not possible. Wavelet analysis presents a solution to this, and is already a well-known tool in other research fields. Until now, the use of Wavelets to analyse EMG signals has been limited to a few research groups.