Effects of Tendinous Tissue on the Torque−Angle Relationship of the Knee Joint

Abstract

[Purpose] This study was designed to clarify the effects of the in vivo fascicle behavior of the vastus lateralis muscle (VL) on the knee joint torque (KJT)- angle (KJA) relationship, and to examine the indirect contributions of tendinous tissues to it. [Subjects and Methods] Fifteen males performed voluntary (VOL) and electrically (ELE) stimulated isometric knee extensions, at KJAs of 30, 60 and 90˚. For the ELE condition, electrical stimulation (ES) of 20 Hz was applied to the VL at 10 different intensity levels. [Results] In VOL, positive relationships were observed between EMG and KJT. Movement of the fascicle increased with KJA. In ELE, KJT was constant at 30˚ and gradually increased at larger KJA with ES intensity. As KJA decreased, fascicle movement in the proximal direction increased. [Conclusion] The results suggest that the KJT-KJA relationship is influenced by the behavior of tendinous tissue due to there being more slack in the tissue in extended positions.