Heel lifts (intervention group): Participants allocated to the intervention group will be given a pair of commercially available heel lifts (Clearly Adjustable) for bilateral use. The heel lifts are 12 mm in height and made from firm (Shore A 90) multi-layered clear vinyl. To maximise comfort, a 3.2 mm PPT Ultralux top cover will be adhered to the top surface. The heel lifts will be reduced in 1 mm increments if required (e.g., heel slippage) and the final height will be recorded at baseline. Sm