Influence of joint position on ankle dorsiflexion in humans

• DOI: 10.1152/jappl.1981.51.1.160
• Publication Date: 2017-12-25T07:39:38Z
• Authors: E. Marsh; D. Sale; A. J. McComas; J. Quinlan
• Keywords: Tibialis anterior muscle; Sitting; Ankle dorsiflexion

A method is described for investigating the contractile properties of dorsiflexor muscles ankle. With joint in midposition tibialis anterior was found to contribute less than half maximum voluntary torque, remainder presumably being provided by long extensors toes. The mean contraction and half-relaxation times healthy young men were 81.2 +/- 7.4 (SD) ms 83.6 17.2 ms, respectively. When stretched, twitch became slower more complete fusion contractions occurred during tetanic stimulation at low frequencies. Stimulation 30 40 Hz disclosed that optimum length muscle corresponded about 10 degrees plantarflexion. Maximum torque also developed plantarflexion decreased sharply as ankle dorsiflex beyond 5 degrees. position assumed rest depended on whether subject sitting, standing, or lying, but always greater, plantarflexed direction, "optimum" development. At rates continued increase throughout full range plantarflexion, probably because elasticity tendon. During effort motoneuronal excitability did not appear be influenced significantly changes angle.