Elliott B C, Wilson G J, Kerr G K
Department of Human Movement and Recreation Studies, University of Western Australia, Nedlands.
Med Sci Sports Exerc. 1989 Aug;21(4):450-62.
The performance of ten elite powerlifters were analyzed in a simulated competition environment using three-dimensional cinematography and surface electromyography while bench pressing approximately 80% of maximum, a maximal load, and an unsuccessful supramaximal attempt. The resultant moment arm (from the sagittal and transverse planes) of the weight about the shoulder axis decreased throughout the upward movement of the bar. The resultant moment arm of the weight about the elbow axis decreased throughout the initial portion of the ascent of the bar, recording a minimum value during the sticking region, and subsequently increased throughout the remainder of the ascent of the bar. The electromyograms produced by the prime mover muscles (sternal portion of pectoralis major, anterior deltoid, long head of triceps brachii) achieved maximal activation at the commencement of the ascent phase of the lift and maintained this level essentially unchanged throughout the upward movement of the bar. The sticking region, therefore, did not appear to be caused by an increase in the moment arm of the weight about the shoulder or elbow joints or by a minimization of muscular activity during this region. A possible mechanism which envisages the sticking region as a force-reduced transition phase between a strain energy-assisted acceleration phase and a mechanically advantageous maximum strength region is postulated.
在模拟比赛环境中，使用三维摄影和表面肌电图对十名精英力量举运动员进行了分析，他们在卧推时分别举起约80%的最大重量、最大负荷以及一次未成功的超最大负荷尝试。杠铃向上运动过程中，重物相对于肩部轴的合成力臂（矢状面和横断面）减小。杠铃上升初始阶段，重物相对于肘部轴的合成力臂减小，在停滞区域记录到最小值，随后在杠铃上升的剩余阶段增大。原动肌（胸大肌胸骨部、三角肌前部、肱三头肌长头）产生的肌电图在举起上升阶段开始时达到最大激活，并在杠铃向上运动过程中基本保持这一水平不变。因此，停滞区域似乎并非由重物相对于肩关节或肘关节的力臂增加，或该区域肌肉活动最小化所致。推测了一种可能的机制，将停滞区域设想为应变能辅助加速阶段和机械优势最大力量区域之间的力减小过渡阶段。
