Energy dissipation in soft tissues increases with peak ground reaction force in human walking

The net summed joint work calculated from inverse dynamics analysis of steady state walking is often reported to be nonzero, whereas the total mechanical energy of the body (i.e. kinetic energy and gravitational potential energy) does not change between strides. This discrepancy may be explained by work done on unmodelled soft tissues. The energy dissipated in soft tissues is expected to increase with the magnitude of the external forces acting on the body. We tested this effect with inverse dynamics analysis of overground walking data at various speed and step length combinations. We expected that conditions producing larger collision impacts, such as longer steps, would exhibit more soft tissue energy dissipation. It was found that soft tissue work, as approximated by net joint work, was correlated to peak ground reaction force. This suggests that energy dissipation in soft tissues increases with peak ground reaction force in human walking.