A baseline of dynamic muscle function during gait.

An existing induced acceleration (IA) model was used to create a comprehensive baseline of dynamic muscle function. In this study, 20 control subjects were modelled as three-dimensional linkage systems. Muscle architecture was taken from an existing muscle model. Each subject-specific model was configured with gait data and 36 unit muscle forces were then applied one at a time to each linkage model. After muscle force application, all joint, segment, and centre of mass (COM) accelerations were derived. The results showed that most uni-articular muscles function as expected while some bi-articular muscles function in a paradoxical manner. This indicates that both the local and remote effects of muscles should be considered when assessing dynamic muscle function during gait. The results also agree with previous IA studies, lending support to the validity of IA analysis as a means for understanding dynamic muscle function.