反動動作のバイオメカニクス : 伸張-短縮サイクルにおける筋-腱複合体の動態

抄録

Behavior of muscle-tendon complex(MTC)in stretch-shortening cycle(SSC)have been extensively studied in natural human movements.The purpose of this paper was to review the biomechanical investigations on SSC, especially in vertical jumping.An effective SSC requires three fundamental conditions:a well-timed preactivation of the muscles before touch-down, a short and fast eccentric phase, an immediate transition(short delay)between stretch(eccentric)and shortening(concentric phase).By the preactivation and the stretch-reflex in eccentric phase during take-off, the stiffness of the agonist's MTCs increased.This high level of the stiffness induced the post-tetanic potentiation of contractile component and the well elongation of elastic component in MTC.As a result, the MTC enhanced force output in concentric phase during take-off.The viscoelastic properties of MTC have been examined by the quick release, the vibration, the alpha, and the null-point methods in an animal isolated muscle, and by the quick release, the impulse response, and the ultrasound methods in human, respectively.By using these coefficients, the MTC in human jumping was modeled and simulated.The influences of the elasticity and the mechanical energy flow by two-joint muscle were quantitatively determined in these simulation studies.Furthermore, the SSC was studied from viewpoints of the muscle fatigue and the coordination.