Cholewicki J, McGill S M
Department of Kinesiology, University of Waterloo, Ontario, Canada.
J Biomech. 1992 Jan;25(1):17-28. doi: 10.1016/0021-9290(92)90242-s.
The mechanical role of the lumbar posterior ligaments during lifting tasks remains controversial. This study was designed to assess the ligament and disc contribution in resisting trunk flexion moment during extremely heavy lifts performed by national class powerlifters. Direct measurements of lumbar vertebrae kinematics in sagittal plane were obtained from videofluoroscopy utilizing multiple digitizing, correction for optical distortions and digital filtering. Four experienced powerlifters executed three trials, resulting in about 72 mA s of total radiation exposure. In the first trial, joint angles were measured when subjects fully flexed their spines to a point where the passive tissues resisted the flexor moment creating myoelectric silence in the extensor musculature. Next, two conventional deadlift style lifts were executed with the barbell load ranging from 183.7 to 210.9 kg. Four vertebral corners were digitized at a sampling rate of 30 Hz. The relative intervertebral joint angles, distance between the ligament attachment points, shearing and compressive displacements were calculated from a rigid body motion approach. Analysis revealed that except for one trial of one subject, they accomplished their lifts with an amount of lumbar flexion between 1.5 and 13 degrees less than they demonstrated during full flexion. Resultant ligament lengths at the beginning of the lifts ranged from 56.1 to 99.8% of their lengths when the trunk was fully flexed. It was concluded that ligaments did not strain sufficiently to contribute substantial resistance to the trunk flexion moment, relegating this responsibility to the musculature.
在举重任务中，腰椎后韧带的力学作用仍存在争议。本研究旨在评估国家级力量举运动员在进行极重举重时，韧带和椎间盘在抵抗躯干屈曲力矩方面的作用。利用多点数字化、光学畸变校正和数字滤波的视频荧光透视法，直接测量腰椎矢状面的运动学。四名经验丰富的力量举运动员进行了三次试验，总辐射暴露量约为72 mAs。在第一次试验中，当受试者将脊柱完全屈曲到被动组织抵抗屈曲力矩，使伸肌肌肉产生肌电静息的程度时，测量关节角度。接下来，进行两次传统硬拉式举重，杠铃负荷范围为183.7至210.9 kg。以30 Hz的采样率对四个椎体角进行数字化处理。通过刚体运动方法计算相对椎间关节角度、韧带附着点之间的距离、剪切和压缩位移。分析表明，除一名受试者的一次试验外，他们完成举重时的腰椎屈曲程度比完全屈曲时少1.5至13度。举重开始时韧带的最终长度为躯干完全屈曲时长度的56.1%至99.8%。得出的结论是，韧带没有充分拉伸以对躯干屈曲力矩产生实质性抵抗，这一责任由肌肉承担。
