Walking is critical to many everyday activities, but it can be impaired by conditions including ageing, neurological disorders and muscular pathologies. One of the most serious consequences of gait impairments is the inability to maintain the adaptive lower limb mechanics typical of the characteristic, unimpaired swing foot trajectory. 
 The project demonstrated, therefore, that a biomechanically designed SPAE could provide functional active ankle assistance during swing, without an external energy source or electronic control system.