Sports Medical Research Group, Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich 8008, Switzerland; University Centre for Prevention and Sports Medicine, Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich 8008, Switzerland.
Department of Sport Science and Kinesiology, University of Salzburg, Hallein-Ri 5400, Austria.
J Sport Health Sci. 2022 Jan;11(1):14-20. doi: 10.1016/j.jshs.2021.11.004. Epub 2021 Nov 28.
During an experiment, a ski racer equipped with various measurement devices suffered an anterior cruciate ligament (ACL) rupture in his right knee. The aim of this study was to describe the underlying injury mechanism from a functional perspective.
Eight giant slalom turns (i.e., 4 left turns), followed by 1 left turn at which the ACL injury occurred, were recorded by 2 video cameras, electromyography of 4 relevant muscle groups, inertial measurement units to measure knee and hip angles, and pressure insoles to determine ground reaction forces.
Due to a loss of balance, the ski racer began to slide sideways at the apex of a left turn. During sliding, his right (outside) leg was actively abducted upward without touching the ground. The ski racer then attempted to stand up again by dropping his leg back towards the snow surface. The end of this dropping was accompanied by a decrease in electromyographic activity in the knee stabilizing muscles. Once the inside edge of the outer ski caught the snow surface, a rapidly increasing peak force, knee flexion, and an aggressive sudden activation of the vastus medialis muscle were observed, while biceps femoris and rectus femoris further decreased their activation levels. This likely resulted in excessive anterior translation of the tibia relative to the femur, causing damage to the ACL.
Our example emphasizes that ski racers should not get up until they stop sliding. Remember: "When you're down, stay down."
在一次实验中，一位装备了各种测量设备的滑雪运动员在右膝处遭遇前交叉韧带（ACL）撕裂。本研究旨在从功能角度描述潜在的损伤机制。
通过两台摄像机、四个相关肌肉群的肌电图、测量膝关节和髋关节角度的惯性测量单元以及确定地面反作用力的压力鞋垫，记录了 8 个大回转（即 4 个左转弯）和一个发生 ACL 损伤的左转弯。
由于失去平衡，滑雪运动员在左转弯顶点开始向侧面滑动。在滑动过程中，他的右腿（外侧）向上主动外展，没有触地。滑雪运动员随后试图通过将腿向后放回雪地再次站起来。在腿下降的过程中，膝关节稳定肌肉的肌电图活动减少。一旦外侧滑雪板的内边缘触到雪地，就会观察到峰值力迅速增加、膝关节弯曲和股四头肌内侧肌的强烈突然激活，而股二头肌和股直肌进一步降低其激活水平。这可能导致胫骨相对于股骨过度向前移位，导致 ACL 损伤。
我们的例子强调，滑雪运动员在停止滑动之前不应站起来。记住：“当你倒下时，就待在原地。”
