title: Effects of isokinetic passive exercise and isometric muscle contraction on passive stiffness.
abstract: [Purpose] The purpose of this study was to investigate the effects of isokinetic passive exercise and motion velocity on passive stiffness. In addition, we also discuss the effects of the contraction of agonist and antagonist muscles on passive stiffness. [Subjects] The subjects were 20 healthy men with no bone or joint disease. [Methods] Isokinetic passive exercise and isometric muscle contraction were performed on an isokinetic dynamometer. The angular acceleration measured by the accelerometer was compared before and after each task. [Results] After the passive exercise, the angular acceleration increased in the phase of small damped oscillation. Moreover, the effect was higher at high-speed movement. The angular acceleration was decreased by the contraction of the agonist muscle. Conversely, the angular acceleration was increased by the contraction of the antagonist muscle. [Conclusion] Isokinetic passive exercise reduced passive stiffness. Our results suggest the possibility that passive stiffness is increased by agonist muscle contraction and decreased by antagonist muscle contraction.
authors.affiliation: Department of Rehabilitation, Kanazawa Red Cross Hospital, Japan ; Doctoral Course of Rehabilitation Science, Division of Health Sciences, Graduate School of Medical Science, Kanazawa University, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Terada
authors.forename: Hiroichi
authors.initials: H
authors.lastname: Miaki
authors.forename: Keita
authors.initials: K
authors.lastname: Uchiyama
authors.forename: Shozo
authors.initials: S
authors.lastname: Hayakawa
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Yamazaki
keywords: Angular acceleration; Isokinetic passive exercise; Passive stiffness