For data collection participants will walking along a 15 m aisle at a self-selected speed and in a natural way. The inertia sensor will be setted at the lower lumbar level (between L4-L5) with a semi-elastic belt. The device will acquire acceleration values (along three orthogonal axes: anteroposterior, mediolateral and superiorinferior) that will be transmitted via Bluetooth to a PC and processed with a software (BTS Bioengineering G-Studio®) to extract the following gait parameters: Step length; Gait speed; Cadence; Position and duration of the swing phase; Duration of the double support; Pelvic tilt.