How Does Induced Deceleration of One Treadmill’s Belt in the Pre-Swing Gait Phase Change Gait Pattern?

Abstract

This study aimed to investigate how external perturbations caused by the treadmill belt’s deceleration during the pre-swing phase affect gait kinematics and kinetics in young adults. Twenty-one healthy young females walked on a treadmill in a virtual environment (GRAIL, Motek), where unexpected perturbations were applied to the left belt, mimicking a ‘trip-like’ effect at toe-off. The spatiotemporal, kinematic, and kinetic parameters were analyzed during two cycles. The first cycle involved the first perturbation and the response to it. The second included a gait cycle without the perturbation (treadmill gait). The perturbation resulted in an increased stride duration for both limbs when compared to the treadmill gait. The perturbed limb had a longer support phase, while the reactive limb had the longest double stance phase. The responding limb exhibited more than double the ankle plantarflexion compared to the normal treadmill gait and the perturbed limb. At the hip joint, both limbs showed significantly higher values, with a 40.8% increase in flexion and a 227% increase in extension for the perturbed limb, and a 24.5% increase in flexion and a 212% increase in extension for the responding limb, compared to the treadmill gait. Muscle torque was generally lower in most joints for both limbs, except for notably higher hip and knee extensor values for the perturbed limb. The responding limb exhibited lower values for the ankle, knee, and hip joints, indicating unexpected muscle activity patterns. Studying treadmill belt deceleration during pre-swing gait can provide valuable insights into biomechanical adaptations and motor control strategies.