Kingma I, van Dieën J H, de Looze M, Toussaint H M, Dolan P, Baten C T
Amsterdam Spine Unit, Institute for fundamental and clinical human movement sciences, Faculty of Human Movement Sciences, Vrije Universiteit, The Netherlands.
J Biomech. 1998 Jun;31(6):527-34. doi: 10.1016/s0021-9290(98)00045-1.
Asymmetric lifting is associated with an increased risk of low back disorders. Especially in lifting movements, characterized by a small amount of asymmetry, it is still the question if asymmetric lumbosacral torques occur, or if subjects try to avoid asymmetric back loading by twisting their pelvis with respect to the feet. An increase of the lifting speed or the box weight might amplify the lumbar torques but might also result in an attempt to limit further increase of asymmetric torques by increasing pelvic twist. In the current study, asymmetrical lifting movements were analyzed with the aid of a 3D linked segment model, using cuffs mounted to the body segments. Eight subjects performed lifting movements with five different asymmetry conditions, ranging from 0 to 90 degrees lifting asymmetry with respect to the sagittal plane, using two lifting speeds and two box weights. A significant increase in lateral flexing and twisting low back torque was found for each increase in asymmetry of the lifting movement. Pelvic twist accounted more or less constantly for about 25% of the lifting asymmetry and was hardly influenced by lifting speed or box weight. Even for 10 or 30 degrees of lifting asymmetry, subjects did not twist their pelvis far enough to avoid asymmetric loading of the low back. Assuming that asymmetric loading of the low back is more strenuous to the spine than symmetric loading, the current results indicate that even small deviations of a lifting movement from the sagittal plane can explain an increased risk of low back disorders.
不对称提举与下背部疾病风险增加有关。特别是在具有少量不对称特征的提举动作中，仍然存在这样的问题：是否会出现不对称的腰骶部扭矩，或者受试者是否会通过相对于双脚扭转骨盆来避免背部不对称负荷。提举速度或箱子重量的增加可能会放大腰部扭矩，但也可能导致试图通过增加骨盆扭转来限制不对称扭矩的进一步增加。在当前的研究中，借助三维链接节段模型，使用安装在身体节段上的袖带来分析不对称提举动作。八名受试者在五种不同的不对称条件下进行提举动作，相对于矢状面的提举不对称范围为0至90度，使用两种提举速度和两种箱子重量。发现提举动作的不对称性每增加一次，腰部侧屈和扭转扭矩就会显著增加。骨盆扭转或多或少持续占提举不对称的约25%，并且几乎不受提举速度或箱子重量的影响。即使提举不对称10度或30度，受试者也没有将骨盆扭转到足以避免下背部不对称负荷的程度。假设下背部的不对称负荷比对称负荷对脊柱更费力，当前结果表明，即使提举动作与矢状面有很小的偏差，也可以解释下背部疾病风险的增加。
