Oliver Gretchen D, Dougherty Christopher P
Department of Health, Kinesiology, Recreation, and Dance, University of Arkansas, Fayetteville, Arkansas, USA.
J Strength Cond Res. 2009 Mar;23(2):401-5. doi: 10.1519/JSC.0b013e31818f08d0.
This study examined the effectiveness of a functional hamstring training exercise, the razor curl on conditioning the hamstring and gluteal musculature. Eight healthy, female intercollegiate athletes participated (mean age 20.8 +/- 3.9 years; mean height, 177.8 +/- 10.9 cm; mean weight, 67.3 +/- 9.9 kg). Electromyographic (EMG) data were collected on the following muscles: medial hamstring (semimembranosus and semitendinosus), biceps femoris, gluteus medius, and gluteus maximus while participants performed the razor curl. The functional positioning of the razor curl showed maximum activation of the medial hamstring muscle group of up to 220% of its maximum voluntary isometric contraction (MVIC), just as the biceps femoris displayed a max of up to 140% of MVIC. Maximum activation of the hamstrings and gluteals were observed from the point of 90 degrees of hip flexion to the point of knee flexion beyond 90 degrees . These data reveal that the razor curl does indeed activate the hamstring musculature and based on the mechanics of the razor curl one can train in a more functional position. It is known biomechanically that flexing the hip allows for a lengthening contraction of the hamstring at the hip, thus allowing for a more optimal forceful contraction of the hamstrings at the knee. In conclusion, the razor curl hamstring exercise is designed to increase hamstring contractibility by placing the hip into flexion. By including strengthening the hamstring in a functional position one accentuates other land based training methods such as jump landing training in efforts to ultimately decrease the susceptibility of anterior cruciate ligament injury.
本研究考察了一种功能性腘绳肌训练练习——剃刀弯举对腘绳肌和臀肌的训练效果。八名健康的大学女子运动员参与了研究（平均年龄20.8±3.9岁；平均身高177.8±10.9厘米；平均体重67.3±9.9千克）。在参与者进行剃刀弯举时，采集了以下肌肉的肌电图（EMG）数据：内侧腘绳肌（半膜肌和半腱肌）、股二头肌、臀中肌和臀大肌。剃刀弯举的功能定位显示，内侧腘绳肌群的最大激活程度达到其最大自主等长收缩（MVIC）的220%，股二头肌的最大激活程度则达到MVIC的140%。从髋关节屈曲90度到膝关节屈曲超过90度的过程中，观察到腘绳肌和臀肌的最大激活。这些数据表明，剃刀弯举确实能激活腘绳肌，并且基于剃刀弯举的力学原理，可以在更具功能性的位置进行训练。从生物力学角度可知，髋关节屈曲会使腘绳肌在髋关节处进行拉长收缩，从而使腘绳肌在膝关节处能进行更优化的强力收缩。总之，剃刀弯举腘绳肌练习旨在通过使髋关节屈曲来增加腘绳肌的收缩能力。通过在功能性位置增强腘绳肌，可强化其他诸如跳跃落地训练等陆上训练方法，最终降低前交叉韧带损伤的易感性。
