MEASUREMENT OF MUSCLE-FIBER DISPLACEMENT DURING CONTRACTION BY REAL-TIME ULTRASONOGRAPHY IN HUMANS

The contact point (P) made by both the echoes of the aponeurosis and f rom interspaces among fascicles of the tibialis anterior muscle was de tected by real-time ultrasound scanning in 12 adults. Movement in the location of P was observed during muscle contraction and its displacem ent was related to changes in ankle joint angles (r = 0.81, P < 0.01), i.e. P shifted proximally when the ankle joint was dorsiflexed. There was also a significant positive correlation between the degree of dor siflexion and the velocity related to the change in location of P (r=0 .84, P<0.01). Ultrasound measurements of the displacement and the velo city of P were reproducible as there was no variation noticed among me asurements on different days. It is suggested from these results that the displacement of P reflected changes in muscle length during contra ction and that this amount of change corresponded to changes in joint angles.