DO LIFTING BELTS PROTECT THE BACK DURING SUDDEN LOADING

提升带在预防下腰中的生物力学作用 伤害一直是争论的主题。但最近的 研究表明，提升带确实限制了躯干在 在被动运动测试和提升过程中的正面和横向平面 协议.这是通过躯干运动的限制，或者说， 换句话说，提升带可以提供躯干的刚性 最大的好处。流行病学研究表明， 意外的负荷经常与下背部疾病的发作有关 (LBD的）。这些事件，无论是由突然施加的负荷组成， 身体，或快速躯干运动在一个滑，创造大的内部 脊柱和它的支撑结构上的负荷， 试图消除扰动以前的研究表明，当 这些事件是可以预见的，主干准备，主要是通过 肌肉共同收缩，这样姿势紊乱和肌肉 加载脊柱的力显著减小。然而，更多的时候， 这些扰动是无法预料的， 躯干要做好准备据推测， 提升带可以保护工人免受所遇到的极端载荷 在不可预见的装载事件期间。因此，两人的目标 拟议的研究是确定起重带是否能保护个人 暴露于躯干的突然负荷。将招募20名受试者 在每一个拟议的实验服务。两项研究将 调查提升带的效果，并结合预期的 负载（无论受试者是否被蒙住眼睛），以及负载是否 相对于身体的正中矢状面是不对称的。十树干 在扰动期间，将用表面肌电图对肌肉进行采样 其中重量的大小相当于受试者体重的10%， 躯干伸展强度，允许在装载前下降一米 躯干在第一项研究中，躯干将直接加载到 下落的重物将通过缆绳和滑轮连接到箱子上 受试者佩戴的挽具。在这项研究中，受试者还将 绑在骨盆约束系统上，从而消除了 由于四肢的反应，并允许直接评估 腰带对躯干肌肉组织的影响躯干运动将通过以下方式测量 电子测角器在第二项研究中，独立受试者将 通过抓住一个容器并将重物放入其中来装载。这 实验将允许评估主干之间的相互作用， 下肢在突然负荷时， 提升带动力学和运动学数据将使用两个 测力板四摄像头光电运动分析系统。这些数据 将用于逆动态生物力学模型，以确定 踝关节、膝关节、髋关节和L5/S1节段的净力矩变化， 提升带。

The biomechanical role lifting belts play in the prevention of low-back injury has been the subject of considerable debate. However, recent studies have shown that lifting belts do restrict the trunk motion in the frontal and transverse planes during passive motion tests and in lifting protocols. It is this through this restriction of trunk motion, or in other words the stiffening of the torso, that lifting belts may provide the greatest benefit. Epidemiological studies have indicated that sudden unexpected loading is frequently related to the onset of low-back disorder (LBD's). These events, whether they consist of a sudden load imposed upon the body, or a rapid trunk motion during a slip, create large internal loadings on the spine and it's supporting structures as the muscles attempt to null the perturbation previous research has shown that when these events can be anticipated the trunk is prepared, primarily through muscular cocontraction, such that the postural disturbance and the muscle forces loading the spine are significantly reduced. More often, however, these perturbations are unanticipated leaving little opportunity for the torso to be prepared. It is hypothesized that the stiffening effects of the lifting belt may protect workers from the extreme loads encountered during unanticipated loading events. Thus, the objective of the two proposed studies is to determine whether lifting belts protect individuals exposed to sudden loading of the torso. Twenty subjects will be recruited to serve in each of the proposed experiments. Both studies will investigate the effect of the lifting belt combined with the expectancy of loading (whether or not the subject is blindfolded), and whether the load is asymmetric with regard to the body's mid-sagittal plane. Ten trunk muscles will be sampled with surface electromyography during perturbations in which a weight, of a magnitude equivalent to 10 percent of a subject's trunk extension strength, is allowed to fall one meter prior to loading the torso. In the first study the torso will be loaded directly in that the falling weight will be attached via cables and pulleys to a chest harness worn by the subject. In this study the subjects will also be strapped into a pelvic restraint system, thereby, removing the variation due to the response of the extremities and allowing a direct evaluation belt's effect on the trunk musculature. Trunk motions will be measured by an electro-goniometer. In the second study free-standing subjects will be loaded by holding a container into which a weight is dropped. This experiment will allow an evaluation of the interplay between the trunk and the lower extremities during sudden loading and it's sensitivity to the lifting belt. Kinetic and kinematic data will be obtained using a two forceplate four camera opto-electronic motion analysis system. These data will be used in an inverse dynamic biomechanical model to determine the change in the net moments at the ankle, knee, hip, and L5/S1 level due to the lifting belt.