Propulsive and braking mechanisms during acceleration and deceleration in human gait

Understanding propulsive and braking mechanisms during gait acceleration and deceleration is essential for ensuring gait stability in daily life.

We aimed to clarify propulsive and braking mechanisms during accelerating and decelerating human gait by analyzing the ground reaction force (GRF) and center of mass external moment (COM M_ext).

We requested 30 healthy young adults to walk under four conditions (normal, maximum, accelerated, decelerated) while kinematic and kinetic data were recorded using a 3D motion capture system and force plates. GRF, COM M_ext, and spatiotemporal gait parameters were analyzed.

Accelerated walking (AW) increased walking velocity and step length, while decelerated walking (DW) reduced them. AW had significantly reduced GRF posterior components in early stance phase, and higher GRF anterior and vertical components in the late stance, resulting in a reduced COM M_ext (larger anterior rotation momentum) in the late stance. DW showed significantly elevated GRF vertical and posterior components in the early stance, resulting in a higher COM M_ext (smaller anterior rotation momentum) in the early stance.

Acceleration was characterized by elevated propulsive and vertical GRF during the late stance to facilitate COM forward rotation. Deceleration was characterized by elevated braking and vertical GRF in the early stance to reduce the abrupt COM forward rotation. Our findings may help the development of effective programs aimed at improving acceleration and deceleration abilities during gait.