The effect of walking surface on upper limb dynamics measured using inertial sensors

This study uses the Xsense MTx sensors for monitoring head and trunk motion during free walking activity over different ground surfaces i.e., tiled, cemented and cobbled surfaces. The MTx sensors are small in size and unobtrusive and do not cause any discomfort to the subjects. These sensors are easy to use for the outdoor walking experiment and require only a laptop to receive data. Using two MTx sensors, 3D acceleration signals (vertical, medio-lateral, & anterior-posterior) were recorded for the head and trunk segments and compared for the free walk on a defined route. This is a continuation of earlier research carried out at Kings College London [13]. The aim of this paper is to compare and investigate the relationship between the power spectral density of the head and trunk vertical, anterior-posterior and particularly medio-lateral acceleration over regular and irregular surfaces. It was found that the magnitude of the power spectra of the vertical acceleration at the trunk was higher when walking over irregular (cobbled) surface as compared to the level (tiled) surface. The power spectra of the head acceleration also varied over the surfaces but the difference was not significant. The medio-lateral acceleration at the head oscillated at a much lower frequency as compared to the vertical acceleration signal.