Stiffness of the lower extremities during landing / 中国组织工程研究

ABSTRACT

BACKGROUND: Downhill running has been found to cause a significant change in the stiffness of the support leg, thus affecting the magnitude and speed of the center of pressure travel. If the stiffness cannot effectively adjust the impact of exercise, sport performance will be weakened and even induce sport injuries. OBJECTIVE: To understand the stiffness to be as the mechanical parameters of human movement, and to assess the mechanisms underlying musculoskeletal system regulating stiffness. METHODS: Medline and CNKI databases were retrieved for relevant articles using the keywords of "landing, spring-mass model, stiffness, human body movement" in English and Chinese, respectively. The stiffness model, stiffness assessment, as well as the role of stiffness during human movement and its influencing factors were reviewed, thereby revealing the significance of stiffness during human movement. RESULTS AND CONCLUSION: When the human body interacts with the ground, the visual information is different, and the neuromuscular system generates coordinated control to arrange appropriate muscle activity of the lower extremities, such as stiffness regulation. The movement settings, working condition, and individual factors all make effects on the stiffness during human movement, and the stiffness efficacy can be controlled by changing the dynamic and kinematic parameters during movement. Appropriate adjustment of the stiffness can promote the human movement performance, and avoid or reduce sport injuries. Running and jumping are the indispensable movements, and taking off is the key step during jumping action, and the stiffness control during taking off action combined with sports skills can improve the sport performance. These results indicate that the vertical stiffness and leg stiffness will be changed with the human actions, accompanied with changes in the stiffness of hip, knee, and ankle joints. In addition, the spring-mass model is helpful for understanding the movement performance and preventing exercise injuries.