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Journal of Healthcare Engineering
Volume 2017 (2017), Article ID 8927415, 7 pages
Research Article

Joint Torque and Mechanical Power of Lower Extremity and Its Relevance to Hamstring Strain during Sprint Running

1College of Physical Education, Nanchang University, Nanchang 330031, China
2School of Kinesiology, Shanghai University of Sport, Shanghai 200438, China
3Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai 200438, China
4Teaching and Research Division of Physical Culture, Tsinghua University, Beijing 100083, China

Correspondence should be addressed to Weijie Fu; nc.ude.sus@eijiewuf and Yu Liu; nc.ude.sus@uiluy

Received 22 February 2017; Revised 11 May 2017; Accepted 29 May 2017; Published 12 July 2017

Academic Editor: Jie Yao

Copyright © 2017 Yunjian Zhong et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The aim of this study was to quantify the contributions of lower extremity joint torques and the mechanical power of lower extremity muscle groups to further elucidate the loadings on hamstring and the mechanics of its injury. Eight national-level male sprinters performed maximum-velocity sprint running on a synthetic track. The 3D kinematic data and ground reaction force (GRF) were collected synchronously. Intersegmental dynamics approach was used to analyze the lower extremity joint torques and power changes in the lower extremity joint muscle groups. During sprinting, the GRF during the stance phase and the motion-dependent torques (MDT) during the swing phase had a major effect on the lower extremity movements and muscle groups. Specifically, during the stance phase, torque produced and work performed by the hip and knee muscles were generally used to counteract the GRF. During the swing phase, the role of the muscle torque changed to mainly counteract the effect of MDT to control the movement direction of the lower extremity. Meanwhile, during the initial stance and late swing phases, the passive torques, namely, the ground reaction torques and MDT produced by the GRF and the inertial movement of the segments of the lower extremity, applied greater stress to the hamstring muscles.