In vivo force-velocity relation of human muscle: a modelling from sinusoidal oscillation behaviour.

Isokinetic tests performed on human muscle in vivo during plantar flexion contractions lead to torque-angular velocity relationships usually fitted by Hill's equation expressed in angular terms. However, such tests can lead to discrepant results since they require maximal voluntary contractions performed in dynamic conditions. In the present study, another way to approach mechanical behaviour of a musculo-articular structure was used, i.

Viscous properties of human muscle during contraction.

The purpose of this study was to determine viscous properties of human muscle during plantarflexion efforts. Experiments were performed on 17 subjects with an ankle ergometer allowing sinusoidal oscillations during isometric contractions and isokinetic movements. Sinusoidal oscillations led to the expression of (i) Bode diagrams of the musculo-articular system allowing the determination of a damping coefficient (Bbode); and (ii) a viscous coefficient (Bsin) using an adaptation of Hill's equation to sinusoidal oscillations.