Ageing Effects on the Mechanical Energy Cost of Walking

The mechanics of human gait have been considered to minimize the mechanical energy costs of transporting the body. With ageing, however, there are adaptations to gait that may be less mechanically efficient than younger adults’ locomotion. The current study compared the mechanical energy efficiency of gait in young and older adults by characterizing the whole body center of mass mechanics. The efficiencies of the inverted-pendulum model during the single support phase and step-to-step transition during double support were investigated. Older adults walked slower than young controls with shorter and wider steps, and consequently their total energetic cost was lower due to the reduced kinetic energy associated with shorter steps and lower walking velocity. There was, however, no evidence of age-related impairments to mechanical energy efficiency. It was concluded that in preferred speed unobstructed walking ageing leads to gait adaptations that encourage greater stability without increasing the mechanical energy cost.