A new system to deliver vibration, measure motion and EMG reaction for forearm muscles

This study aims to measure motion and neuromuscular activity of the forearm flexor muscle in response to mechanical, vibratory stimuli. In particular, the vibration frequency that maximizes the neuromuscular response was searched. A dedicated measuring system was realised: the mechanical stimulus was provided to subject’s hand by a controlled, vibrating plate; the forearm muscles response was detected through sEMG and tri-axial accelerometric signals. Sinusoidal vibrations at different frequencies in the range 14–32 Hz were delivered. The RMS of the sEMG signal and a accelerometric transfer function (i.e. ratio between acceleration of the plate and acceleration of the target muscle) were computed for the frequency range and then analysed. Preliminary results on six subjects show different mechanical and neuromuscular behaviour between the subjects but also intra-subject variability due to posture and initial state of the muscle. The EMG response to vibration depends on frequency.