Effects of Mass and Momentum of Inertia Alternation on Individual Muscle Forces during Swing Phase of Transtibial Amputee Gait

摘要

A computer simulation was carried out to investigate the forces of lower extremitymuscles in the swing phase of a transtibial amputee gait. With each muscle as an idealforce generator, the lower extremity was simulated as a two-degrees of freedom linkagewith the hip and knee as its joints. Kinematic data of hip and knee joints were recordedby a motion analysis system. Through a static optimization approach, the forces exertedby muscles were determined so that recorded hip and knee joint angles were produced.Simulation results showed that when the mass of prosthetic foot is increased, muscleforces increase, too. This result is in accord with experimental and theoretical studiesthat reported an increase in leg mass lead to higher electromyography activity ofmuscles, and energetic of walking. However, since prosthetic foot moment of inertia issmaller than that of thigh and prosthetic shank, its alternation does not have noticeableeffect on muscle forces.