Mechanical energy fluctuation in lower limbs during walking in participants with and without total hip replacement

Mechanical energy fluctuation of the segments in the lower limbs during walking has not been fully investigated. It was hypothesised that the segments of the lower limbs may work as a pendulum, i.e., the kinetic and potential energies exchanged out of phase. This study aimed to investigate energy changes and recovery during gait in hip replacement patients. The gait data for 12 participants with total hip replacement and 12 age-matched controls were compared. The kinetic, potential, and rotative energies for the whole lower limb and thigh, calf, and foot, were calculated. The effectiveness of a pendulum effect was analysed. Gait parameters, e.g., walking speeds, cadence, and stride length were calculated. The results showed that the thigh had significant effectiveness as a pendulum during gait with an energy recovery coefficient of approximately 40% while the calf and foot were less like a pendulum during gait. In comparison, energy recoveries of the lower limbs in the two groups were not significantly different. If the centre of the pelvis was considered as approximate to the centre of mass, however, the control group had a higher energy recovery than the total hip replacement group by roughly 10%. This study concluded that the mechanical energy recovery mechanism in the lower limbs during walking exists for two groups.