Musculoskeletal Rehabilitation Research Group, Faculty of Kinesiology and Rehabilitation Sciences, KU Leuven, Leuven, BELGIUM.
Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UNITED KINGDOM.
Med Sci Sports Exerc. 2020 Aug;52(8):1658-1667. doi: 10.1249/MSS.0000000000002308.
Athletes returning to sport after anterior cruciate ligament reconstruction (ACLR) demonstrate prolonged changes in landing kinematics, kinetics, and muscle activation, predisposing them for reinjury, knee osteoarthritis, and/or knee instability. So far, researchers have been focusing on how kinematics and kinetics change in every joint separately. However, as the human body operates within a kinetic chain, we will assess whether single-joint changes are associated with whole-body changes.
Twenty-one athletes who had an ACLR and 21 uninjured controls performed five unilateral landing tasks, whereas lower limb kinematics, kinetics, and muscle activations of vastus medialis, vastus lateralis, biceps femoris, semitendinosus, semimembranosus, gastrocnemius, and gluteus medius were recorded. Single-joint landing kinematics, kinetics, and muscle activations of the ACL-injured leg were compared with the uninjured leg and compared with the control group. Whole-body changes were assessed by decomposing movements into fundamental components using marker-based principal component analysis (PCA).
We found several single-joint changes in landing kinematics, kinetics, and muscle activations in the athletes with ACLR that were seen across all tasks and therefore of major interest as they are likely to occur during sports as well. Hamstrings activation increased and external knee flexion moments decreased in the ACL-injured leg compared with their uninjured leg. Furthermore, hip adduction moments and knee abduction angles decreased compared with the control group. The PCA could detect changes in whole-body movement, which were task-specific.
Athletes with ACLR still show protective task-independent single-joint kinematic, kinetic, and muscle activation changes during single-leg landings at the time of return to sport. These single-joint changes were not consistently accompanied by changes in whole-body movements (revealed by marker-based PCA). Whole-body expressions of the single-joint compensations are likely to be affected by the demands of the task.
前交叉韧带重建（ACL）后重返运动的运动员表现出长时间的落地运动学、动力学和肌肉激活改变，使他们易受伤、膝骨关节炎和/或膝关节不稳定。到目前为止，研究人员一直专注于每个关节的运动学和动力学如何单独改变。然而，由于人体在动力链中运作，我们将评估单关节的变化是否与全身变化有关。
21 名 ACL 重建后的运动员和 21 名未受伤的对照组运动员进行了五次单侧落地任务，同时记录了股直肌、股外侧肌、股二头肌、半腱肌、半膜肌、腓肠肌和臀中肌的下肢运动学、动力学和肌肉激活。将 ACL 损伤腿的单关节落地运动学、动力学和肌肉激活与未损伤腿和对照组进行比较。使用基于标记的主成分分析（PCA）将运动分解为基本成分，以评估全身变化。
我们发现 ACL 重建后的运动员在落地运动学、动力学和肌肉激活方面存在几种单关节变化，这些变化在所有任务中都存在，因此非常重要，因为它们也可能在运动中发生。与未损伤腿相比，ACL 损伤腿的腘绳肌激活增加，膝关节外屈力矩减小。此外，与对照组相比，髋关节内收力矩和膝关节外展角度减小。PCA 可以检测到全身运动的变化，这些变化是特定于任务的。
ACL 重建后的运动员在重返运动时进行单腿落地时，仍然表现出独立于任务的单关节运动学、动力学和肌肉激活保护变化。这些单关节变化并不总是伴随着全身运动的变化（基于标记的 PCA 揭示）。单关节补偿的全身表达可能受到任务需求的影响。
