ULTRASONOGRAPHY GIVES DIRECTLY BUT NONINVASIVELY ELASTIC CHARACTERISTIC OF HUMAN TENDON IN-VIVO

To obtain an insight into tendon elasticity during human movement, a r eal-time ultrasonography was applied to the contracting tibialis anter ior muscle. The insertion point of fascicles onto the aponeurosis was clearly visualized, and its position relative to a fixed marker on the skin moved proximally (triangle 1) according to the increasing dorsif lexion force (triangle F) with a fixed ankle joint. Notably, the trian gle 1-triangle F relationship in the tendon was found to be quadratic in nature (triangle F=c triangle l(2); c=1.48 similar to 2.24, r=0.985 similar to 0.992, n=9) as has been reported in the isolated tendon, a lthough the triangle F-triangle 1 curves were slightly underestimated in comparison with the stiffness constant estimated from tendon archit ecture, This underestimation might be caused by changes in the height of the foot arch with the application of force.