Koyanagi Maki, Shino Konsei, Yoshimoto Yoji, Inoue Satoru, Sato Mutsumi, Nakata Ken
Faculty of Rehabilitation, Shijonawate Gakuen University, 5-11-10, Hojo, Daito-city, Osaka, Japan.
Knee Surg Sports Traumatol Arthrosc. 2006 Jan;14(1):88-93. doi: 10.1007/s00167-004-0609-2. Epub 2005 May 21.
This study was performed to investigate the effects of changes in the skiing posture on mechanical stress across the knee joint. The aim of the present study was to establish a safer form of skiing for the prevention of injury to the anterior cruciate ligament of the knee (ACL). Ten healthy volunteers were placed on a force plate on an artificial slope, and assumed forward and backward bending postures with a single leg by changing their centre of gravity. The knee flexion angles were limited to approximately 30 degrees by orthotics in each posture. Joint moments of the lower extremity were analyzed using a motion analysis system, and the muscle activities of the lower extremity were recorded by EMG and digitised to integrated EMG in each posture. In addition, extrusion of the lower leg by the boot was measured using a force sensor sheet inserted behind the calf. We found that the extension moment of the hip and ankle joints, and muscular activity of the hamstrings were increased in forward bending, whereas the extension moment of the knee and muscular activity of the quadriceps were decreased. Conversely, the muscular activity of the quadriceps, the flexion moment of the hip, extension moment of the knee joint, and pressure of the boot were increased in backward bending, whereas muscular activity of the hamstrings was decreased. The dependency on the hamstrings increased in forward bending in a skiing posture on a slope with slight knee flexion. Therefore, forward bending seemed to be an advantageous posture for the prevention of ACL injury. Conversely, in a backward bending skiing posture, the extension moment of the knee joint produced by muscle contraction of the quadriceps also increased imbalance in the hamstrings. The results of this study suggest that the internal force exerted by the quadriceps, in addition to the passive factor of extrusion of the lower leg by the boot, may contribute to non-contact ACL injury in a backward bending posture while skiing.
本研究旨在调查滑雪姿势变化对膝关节机械应力的影响。本研究的目的是建立一种更安全的滑雪方式，以预防膝关节前交叉韧带（ACL）损伤。十名健康志愿者被放置在人工斜坡上的测力板上，通过改变重心以单腿姿势呈现向前和向后弯曲姿势。在每个姿势下，通过矫形器将膝关节屈曲角度限制在约30度。使用运动分析系统分析下肢的关节力矩，并通过肌电图记录下肢的肌肉活动，并在每个姿势下将其数字化为积分肌电图。此外，使用插入小腿后方的力传感器片测量靴子对小腿的挤压。我们发现，向前弯曲时髋关节和踝关节的伸展力矩以及腘绳肌的肌肉活动增加，而膝关节的伸展力矩和股四头肌的肌肉活动减少。相反，向后弯曲时股四头肌的肌肉活动、髋关节的屈曲力矩、膝关节的伸展力矩以及靴子的压力增加，而腘绳肌的肌肉活动减少。在膝盖轻微屈曲的斜坡上滑雪姿势中，向前弯曲时对腘绳肌的依赖性增加。因此，向前弯曲似乎是预防ACL损伤的有利姿势。相反，在向后弯曲的滑雪姿势中，股四头肌肌肉收缩产生的膝关节伸展力矩也增加了腘绳肌的不平衡。本研究结果表明，除了靴子对小腿的被动挤压因素外，股四头肌施加的内力可能导致滑雪时向后弯曲姿势下的非接触性ACL损伤。
