Temporal symmetries during gait initiation and termination in nondisabled ambulators and in people with unilateral transtibial limb loss

This study investigated the temporal characteristics of gait initiation and gait termination. Ten nondisabled adult vol- unteers and ten people with unilateral transtibial limb loss per- formed starting and stopping for slow, normal, and fast walking speeds. We used kinematic and anthropomorphic data to deter- mine the body center of mass (BCOM) position of each subject. The BCOM acceleration was derived by double-differentiating the position data. An averaged BCOM acceleration was calcu- lated by a filtering of the instantaneous acceleration data at a cutoff frequency set by the cadence for elimination of the step-to-step variation. We used this averaged acceleration to calculate the time the volunteers needed to initiate and termi- nate gait. The results support the hypothesis that both nondis- abled ambulators and the subjects with unilateral transtibial limb loss initiate and terminate gait in approximately two steps, regardless of the steady-state walking speed.