Walking efficiency assessment through the analysis of mechanical energy and energy recovery index

The mechanical energy exchanges of normal subjects during walking have been investigated. Two groups of subjects including healthy children and healthy adults participated in this study. Kinematic data have been captured by a motion analysis system composed of 8 TV-cameras with an acquisition frequency of 50 Hz and retro-reflective markers positioned on main reference points of the body. Based on the estimation of mass and centre of mass of the main anatomical segments the kinetic and potential energy were computed. The total mechanical energy along a stride was compared to the kinetic and potential energy excursions as to obtain an index of energy recovery. Preliminary results show that significant differences exist between children and adults and walking efficiency is higher in adults.