Holleran K, Pope M, Haugh L, Absher R
Department of Orthopaedic Surgery, University of Iowa, Iowa City, USA.
Iowa Orthop J. 1995;15:24-8.
Fick hypothesized in 1911 that the erector spinae muscles are not active when the trunk is in the fully flexed position. This effect was later called the flexion-relaxation phenomenon (FRP) and is believed to be the result of the ligaments and other passive elements of the spine taking over the load of the muscles. This study examined the effect of loading on the EMG activity of five males and five females during postures of standing at 45 degrees, 90 degrees, and full flexion. The results showed major differences in the relationship between the electromyographic signal (EMG) of the erector spinae and loading for the four postures. The erector spinae muscles did not activate in positions of full flexion (or even 90 degrees for some subjects) for loading as high as 50% of their maximum voluntary contraction, suggesting that alternative muscles are being activated and that the passive tissues may be put under higher loads than originally thought in these positions. The results suggested that the FRP could be used as a biofeedback tool to illustrate to workers that their muscles are not turning on in the fully flexed positions, and therefore, these positions should be avoided.
1911年，菲克提出假说，认为当躯干处于完全屈曲位置时，竖脊肌并不活跃。这种效应后来被称为屈曲放松现象（FRP），人们认为这是脊柱的韧带和其他被动元件承担了肌肉负荷的结果。本研究考察了在45度、90度站立姿势以及完全屈曲姿势下，负荷对5名男性和5名女性肌电图活动的影响。结果显示，在四种姿势下，竖脊肌的肌电信号（EMG）与负荷之间的关系存在重大差异。对于高达其最大自主收缩50%的负荷，竖脊肌在完全屈曲位置（甚至对某些受试者而言是90度位置）并未激活，这表明其他肌肉正在被激活，并且在这些位置，被动组织可能承受比原本认为的更高的负荷。结果表明，FRP可作为一种生物反馈工具，向工人说明他们的肌肉在完全屈曲位置并未启动，因此应避免这些姿势。
