Beynnon B D, Johnson R J, Fleming B C, Stankewich C J, Renström P A, Nichols C E
McClure Musculoskeletal Research Center, Department of Orthopaedics and Rehabilitation, University of Vermont College of Medicine, Burlington, USA.
Am J Sports Med. 1997 Nov-Dec;25(6):823-9. doi: 10.1177/036354659702500616.
The effects of weightbearing (closed kinetic chain) and nonweightbearing (open kinetic chain) exercises on the biomechanical behavior of an injured anterior cruciate ligament or a healing anterior cruciate ligament graft are unknown. To understand the effects of these exercises on the healing graft, we measured the strain behavior of the normal anterior cruciate ligament in human subjects while they performed squatting, a closed kinetic chain exercise, and active flexion-extension of the leg, an open kinetic chain exercise. The maximum anterior cruciate ligament strain values obtained during squatting did not differ from those obtained during active flexion-extension. Also, anterior cruciate ligament strain values obtained during squatting were unaffected by the application of elastic resistance intended to increase muscle activity. These findings indicate that squatting, which produces a substantial compressive joint force, does not necessarily protect the anterior cruciate ligament more than active flexion-extension of the leg, which is characterized primarily by contraction of the dominant quadriceps muscle. These findings also demonstrate that increasing resistance during the squat exercise does not produce a significant increase in anterior cruciate ligament strain values, unlike increased resistance during active flexion-extension exercise.
负重（闭链）和非负重（开链）运动对受伤的前交叉韧带或正在愈合的前交叉韧带移植物生物力学行为的影响尚不清楚。为了了解这些运动对愈合移植物的影响，我们在人类受试者进行深蹲（一种闭链运动）和腿部主动屈伸（一种开链运动）时，测量了正常前交叉韧带的应变行为。深蹲过程中获得的前交叉韧带最大应变值与主动屈伸过程中获得的值没有差异。此外，深蹲过程中获得的前交叉韧带应变值不受旨在增加肌肉活动的弹性阻力应用的影响。这些发现表明，产生大量关节压缩力的深蹲，不一定比主要以股四头肌收缩为特征的腿部主动屈伸更能保护前交叉韧带。这些发现还表明，与主动屈伸运动中增加阻力不同，深蹲运动中增加阻力不会使前交叉韧带应变值显著增加。
