McHugh M P, Kremenic I J, Fox M B, Gleim G W
Nicholas Institute of Sports Medicine and Athletic Trauma, Lenox Hill Hospital, New York, NY 10021, USA.
Med Sci Sports Exerc. 1998 Jun;30(6):928-32. doi: 10.1097/00005768-199806000-00023.
Musculoskeletal flexibility is typically characterized by maximum range of motion (ROM) in a joint or series of joints. Resistance to passive stretch in the mid-range of motion is a function of the passive mechanical restraints to motion. However, an active contractile response may contribute resistance at terminal ROM.
The purpose of this study was to examine whether maximum straight leg raise (SLR) ROM was limited by passive mechanical forces or stretch-induced contractile responses to stretch.
An instrumented SLR stretch was applied to the right leg of 16 subjects ending at the point of discomfort. Torque was measured with a load cell attached to the ankle. An electrogoniometer was placed on the hip, and the knee was braced in extension. Surface electrodes were placed over the rectus and biceps femoris muscles. Following the instrumented SLR test, maximum ROM was measured goniometrically by a physical therapist using the standard SLR test (PT SLR ROM). Torque/ROM curves were plotted for each subject.
PT SLR ROM was positively related to total energy absorbed (area under the curve) (r = 0.49, P = 0.044), negatively related to the increase in torque from 20 to 50 degrees (r = -0.81, P < 0.0001) and negatively related to energy absorbed from 20 to 50 degrees (r = -0.73, P < 0.001). Minimal stretch-induced hamstring activity was elicited (3 +/- 1% MVC), and the EMG activity was unrelated to PT SLR ROM (r = -0.06, P = 0.8). A combination of the increase in torque from 20 to 50 degrees and total energy absorbed improved the relationship to PT SLR ROM (r = 0.89, P = 0.001). Seventy-nine percent of the variability in maximum SLR ROM could be explained by the passive mechanical response to stretch.
These data lend support to the concept that musculoskeletal flexibility can be explained in mechanical terms rather than by neural theories.
肌肉骨骼柔韧性通常以一个关节或一系列关节的最大活动范围（ROM）为特征。运动中程的被动拉伸阻力是运动的被动机械约束的函数。然而，主动收缩反应可能在终末ROM时产生阻力。
本研究的目的是检查最大直腿抬高（SLR）ROM是受被动机械力限制还是受拉伸诱导的收缩反应限制。
对16名受试者的右腿进行仪器化SLR拉伸，直至不适点。用连接在脚踝处的测力传感器测量扭矩。将电子测角仪置于髋部，膝关节伸直固定。表面电极置于股直肌和股二头肌上。在仪器化SLR测试后，由物理治疗师使用标准SLR测试（PT SLR ROM）通过角度测量法测量最大ROM。为每个受试者绘制扭矩/ROM曲线。
PT SLR ROM与吸收的总能量（曲线下面积）呈正相关（r = 0.49，P = 0.044），与20至50度扭矩的增加呈负相关（r = -0.81，P < 0.0001），与20至50度吸收的能量呈负相关（r = -0.73，P < 0.001）。诱发的拉伸诱导的腘绳肌活动最小（3±1%最大随意收缩），且肌电图活动与PT SLR ROM无关（r = -0.06，P = 0.8）。20至50度扭矩的增加和吸收的总能量的组合改善了与PT SLR ROM的关系（r = 0.89，P = 0.001）。最大SLR ROM中79%的变异性可由对拉伸的被动机械反应解释。
这些数据支持了肌肉骨骼柔韧性可以用机械术语而非神经理论来解释的概念。
