Fig. 1. Myoelectric signals and principle components from the electrical stimulation and tendon tap recordings from the soleus. (A) Myoelectric signals for the electrical stimulation (black lines) and tendon taps (gray lines) for the ten trials for one subject. The artefact for the electrical stimulation is shown by the arrow. (B) The weightings for the first two principle components (PC) are shown that describe the intensity spectra for both the electrical stimulation and tendon tap trials for all subjects (N=100), with the relative proportion of the total signal that they describe. The principle component weightings are shown by solid circles and line. The mean ± S.E.M. intensity spectra for the data (N=100) are shown by the open diamonds. (C) Mean ± S.E.M. scores for PC I and PC II for the electrical stimulation (black symbols) and tendon taps (gray symbols) for all subjects (N=50). The arrows mark vectors in the PC I–PC II scoring plane, which form the reconstructed spectra.