Whole-body vibrations exposure while walking in place

The human body is exposed to vibration while walking on manufacturing platforms or in transports. In order to minimize the risk of pathologies, anti-vibration equipment can be designed to limit the vibration transmitted to specific body segments. Prevention strategies have been developed starting from the vibration transmissibility and from the apparent mass of standing subjects. Little have been done for the optimization of anti-vibration devices for walking workers. Our work aims at investigating the response of the human body while walking in place. For this purpose, a dedicated experimental procedure involving seven participants walking in place over a vibrating platform has been developed. Participants were exposed to harmonic excitation with six different frequencies (5, 10, 15, 20, 25, and 30 Hz), with an amplitude of 2 m.s−2. The inertial force exerted by the walking subjects exposed to the stimulus was measured by four load cells supporting the platform. Simultaneously, tridimensional acceleration signals were collected at the participant right shank, low-back, and mouth. Vibration transmissibility as well as apparent mass were computed as a function of the excitation frequency. Results indicated a higher transmissibility of the vibration at 5 Hz and 10 Hz. Further, the apparent mass of the participants walking in place was estimated between the values reported in the literature when standing in neutral position and when standing in neutral position with knee bent. Future works will include an electromyographical analysis of lower-limb muscles with respect to the excitation frequency.