Unloading shoe The design of the "unloading" shoe to be used in this research will be a modern style of trainer-type shoe with a cosmetically-shaped rocker sole incorporated. The rocker sole will comprise of three circular curves whose arc centres are positioned at the anatomical ankle, hip and knee respectively; assuming a vertical lower limb. This is designed to influence the line of action of the ground reaction force to pass close to the anatomical joint centres and so reduce the moments needed to be generated for ambulation by the muscles acting across those joints in the lower limb. Additionally it is designed to place the ankle into a relatively plantarflexed position where the ankle plantarflexors use less energy than for instance when placed in dorsiflexion. This is in order to unload the calf muscles by providing a simultaneous reduction in ankle range of motion in relative plantarflexion but still moving with a near-normal trajectory. This also optimises the lever arm between the Achilles tendon and the ankle joint so making propulsion, and therefore calf muscle power generation, more efficient. Participants will be provided with a pair of appropriately-sized shoes, which will be produced for this study by an established shoe manufacturer - Chaneco (www.chaneco.co.uk). To allow participants to habituate to wearing the shoes before assessment, they will be allowed to walk around in the shoes at a self-selected pace for at least 5 minutes.