抄録
Stiffness of human tibialis anterior muscle was measured at rest as well as at voluntary contraction by using a newly developed device. The principle of this device is based on the following : When the mechanically vibrating system in this device is pressed to the subject, the resonance frequency of the vibrating system changes by depending upon the stiffness of the subject. Hence stiffness of the subject can be obtained by measuring this resonance frequency.
After several basic parameters, such as the optimal initial bias pressure and the range of vibration in the muscle, were investigated, the following experimental results were obtained.
1. The muscle stiffness increased along with increase of the tension, although the relation between them was not linear.
2. There was a good correlation between the values of stiffness indicated by this device and the subjective sensation of'consistency'of the muscle at various degrees judged by palpation of the muscle with fingertips of experimenters. This result indicates that this device is a useful instrument to measure muscle stiffness non-invasively.
3. When the muscle tension was held constant for several minutes, the values of stiffness gradually increased along with the amplitudes of integrated EMG.
