Functional role and plasticity of mechanical properties and their endurance of muscle and tendon

2019 Fiscal Year Final Research Report

• Project/Area Number: 17H02149
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Sports science
• Research Institution: The University of Tokyo
• Principal Investigator: Kubo Keitaro 東京大学, 大学院総合文化研究科, 准教授 (70323459)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 筋スティッフネス / 筋束長 / 超音波

Outline of Final Research Achievements

We assessed active muscle stiffness with the stretch reflex according to changes (in 110 ms period after stretching) in muscle force and fascicle length during slower angular velocity (100 deg/s). Using this technique, we observed that active muscle stiffness with and without stretch reflex did not change after 10-min of static stretching, which decreased stretch reflex. Furthermore, joint stiffness and active muscle stiffness with and without stretch reflex significantly decreased after repeated hopping exercises, whereas tendon stiffness did not. Furthermore, the relative change in joint stiffness was significantly correlated with that in active muscle stiffness with stretch reflex, but not with those in the other measured variables.

Free Research Field

運動生理学

Academic Significance and Societal Importance of the Research Achievements

本研究では新たに「伸張反射の影響を含むアクテイブ筋スティッフネス」の定量法を提示した。この手法を用いて静的ストレッチングや疲労課題による変化を検証し、アクテイブ筋スティッフネスが伸張反射ではなく、伸張速度の影響を強く受けている結果が得られた。特に、後者（アクテイブ筋スティッフネスと伸張速度の関係）については、トレーニング現場でみられる速度特異性の機序解明につながる可能性がある。