Objective We designed this study to evaluate muscle tone by using a biomechanical method and to provide data for the future studies about muscle tone. Method We evaluated 29 subjects without known neuromuscalar diseases using the biomechanical method. Both plantar flexors of each subject were passively stretched by isokinetic dynamometer from 30oplantar flexion position to 10odorsiflexion position. Peak eccentric torque (PET) and torque threshold angle (TTA) were calculated at angular velocity of 10o/sec, 90o/sec and 300o/sec. Regression lines from torque/position curve at 10o/sec and 300o/sec were considered an intrinsic stiffness index (ISI) and total stiffness index (TSI). Stretch reflex threshold speed (SRTS) was defined as the minimum speed of plantar flexion movement in which EMG reflex activity in plantar flexor muscles is induced. Results The mean of TTA was higher in 10o/sec than in 300o/sec. The means of ISI and TSI were 0.11⁑0.08, and 0.18⁑0.04. The mean of SRTS was 125.2⁑48.3o. No statistical difference in each parameter was found according to the side or gender. Conclusion ISI, TSI, PET, TTA and SRTS using a biomechanical method are thought to be useful parameters for the quantitative assessment of muscle tone change of ankle plantar flexors. |