Schipplein O D, Reinsel T E, Andersson G B, Lavender S A
Department of Orthopedic Surgery, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois, USA.
Spine (Phila Pa 1976). 1995 Sep 1;20(17):1895-8. doi: 10.1097/00007632-199509000-00010.
This was a biomechanical study of the effect of the initial horizontal distance between a person lifting and the load. Experimental data were analyzed using a dynamic rigid link model.
To determine the effect of the initial horizontal load placement on the moments acting on the lumbar spine and the lower extremity joints during lifting, and to determine the role of the lower extremities during lifting from the floor.
Epidemiologic studies have implicated lifting as a cause of back pain, and over 80% of all worker's compensation back injuries are considered to be caused by manual material handling Guidelines have been proposed to increase the safety of lifting, but they are primarily based on static biomechanical analyses, psychophysical data, and physiologic limitations.
Each of 12 male subjects lifted a weight box containing 0 to 300 N, in 100-N increments. Each subject performed 20 lifts--four weights at five horizontal distances (20, 30, 40, 50 and 60 cm). Motion was measured with an optoelectronic system, ground reaction forces were measured with a force plate, and moments were calculated using a rigid link model.
The peak predicted L5-S1 moment increased as the weight and horizontal distance increased. The influence of horizontal distance on moment magnitude was nonlinear. As the distance changed from 20 to 40 cm, the distance-related rate of increase was approximately one-half of that occurring with a distance change from 40 to 60 cm. This can be explained by the need to reach out further, beyond 40 cm, which is accomplished by a deeper flexion of the knees and ankles and an anterior translation of the upper body and arms.
As the horizontal distance at the start of a lift increased, the peak moment acting on the lumbar spine also increased, but the increase was nonlinear. This is explained by a change in the technique of lifting when the distance is 40 cm or greater.
这是一项关于提升者与负载之间初始水平距离影响的生物力学研究。实验数据采用动态刚性连接模型进行分析。
确定提升过程中初始水平负载位置对作用于腰椎和下肢关节的力矩的影响，并确定从地面提升时下肢的作用。
流行病学研究表明，搬运重物是背痛的一个原因，超过80%的工伤背部损伤被认为是由手工搬运材料所致。已提出一些指南以提高搬运的安全性，但它们主要基于静态生物力学分析、心理物理学数据和生理限制。
12名男性受试者每人提升一个装有0至300牛重物的箱子，每次增加100牛。每个受试者进行20次提升——在五个水平距离（20、30、40、50和60厘米）下提升四种重量。运动通过光电系统测量，地面反作用力通过测力板测量，力矩使用刚性连接模型计算。
预测的L5 - S1峰值力矩随重量和水平距离的增加而增加。水平距离对力矩大小的影响是非线性的。当距离从20厘米变化到40厘米时，与距离相关的增加率约为距离从40厘米变化到60厘米时的一半。这可以通过在超过40厘米时需要进一步伸展来解释，这是通过膝盖和脚踝的更深屈曲以及上半身和手臂的向前平移来实现的。
随着提升开始时水平距离的增加，作用于腰椎的峰值力矩也增加，但增加是非线性的。这是由于距离为40厘米或更大时提升技术的变化所解释的。
