Osternig L R, Ferber R, Mercer J, Davis H
Department of Exercise and Movement Science, University of Oregon, Eugene, OR 97403, USA.
Med Sci Sports Exerc. 2001 Jul;33(7):1073-80. doi: 10.1097/00005768-200107000-00002.
The purpose of this study was to assess the effect of joint position and movement speed on hip (HT) and knee (KT) extensor torque, HT/KT ratio (HKR), and anterior tibial shear (S) in presurgical-ACL deficient (PRE; N = 15), post-ACL reconstructed (POST; N = 15), and uninjured controls (CON; N = 15).
Measurements were recorded on a semirecumbent variable resistance, closed-chain dynamometer. Tests were conducted at 1 and 1.5 Hz and maximum speed at 33% and 50% 1RM. HT, KT, and S were recorded during the extension phase of the cycle (85 degrees -25 degrees of knee flexion).
KT was greatest when the knee was more flexed, whereas HT dominated when it was more extended. This suggests that the hamstrings, as a component of the hip extensors, may generate considerable propulsive force during knee extension, which may help counter anterior tibial shear. S increased whereas KT decreased, suggesting that the quadriceps continue to generate shear force despite the decreasing mechanical advantage producing KT. Increasing knee extension speed significantly decreased S in the POST and CON groups. The correlations between KT and S changed from significantly negative to significantly positive as the knee extended from 85 degrees to 25 degrees in the POST and CON groups. This may be related to the orientation of the patellar tendon, relative to the tibial longitudinal axis that shifts from a posterior to anterior direction, as the knee extends.
Joint position and movement speeds affect the magnitude of hip and knee torques and anterior tibial shear. Reducing the magnitude of S during heavy loads may be a normal phenomenon, and POST surgical subjects may retain or regain this function by 1 yr after surgery.
本研究旨在评估关节位置和运动速度对术前前交叉韧带损伤（PRE；n = 15）、前交叉韧带重建术后（POST；n = 15）以及未受伤对照组（CON；n = 15）的髋部（HT）和膝部（KT）伸肌扭矩、HT/KT 比值（HKR）以及胫骨前向剪切力（S）的影响。
在半卧位可变阻力闭链测力计上记录测量数据。测试在 1Hz 和 1.5Hz 频率下进行，最大速度为 33%和 50%的 1 次重复最大值（1RM）。在周期的伸展阶段（膝关节屈曲 85 度至 25 度）记录 HT、KT 和 S。
膝关节屈曲程度越大，KT 越大；而膝关节伸展程度越大，HT 起主导作用。这表明，作为髋部伸肌组成部分的腘绳肌，可能在膝关节伸展过程中产生相当大的推进力，这可能有助于抵消胫骨前向剪切力。S 增加而 KT 降低，这表明尽管产生 KT 的机械优势降低，但股四头肌仍继续产生剪切力。在 POST 组和 CON 组中，增加膝关节伸展速度显著降低了 S。在 POST 组和 CON 组中，随着膝关节从 85 度伸展至 25 度，KT 与 S 之间的相关性从显著负相关变为显著正相关。这可能与髌腱相对于胫骨纵轴从后向前方向的取向有关，随着膝关节伸展，该取向会发生变化。
关节位置和运动速度会影响髋部和膝部扭矩以及胫骨前向剪切力的大小。在重负荷期间降低 S 的大小可能是一种正常现象，POST 手术受试者在术后 1 年可能保留或恢复该功能。
