Occupational Trunk Flexion and Neuromuscular Disturbance

职业性躯干屈曲和神经肌肉紊乱

• 批准号: 7091154
• 负责人: KEVIN P. GRANATA
• 金额: $ 26.13万
• 依托单位: VIRGINIA POLYTECHNIC INST AND ST UNIV
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7091154
• 关键词: biomechanics; clinical research; disease /disorder proneness /risk; human subject; muscle contraction; neuromuscular disorder; occupational disease /disorder; posture; spinal reflex; spine injury

DESCRIPTION (provided by applicant): Working in flexed torso postures increases the risk of occupationally related low-back disorders. These postures apply strain to spinal tissues that cause temporary disturbances in neuromuscular control of trunk muscles. Existing evidence reveals that there are residual effects on spine biomechanics following exposure to flexed postures. Recovery from these disturbances may be incomplete upon initiation of subsequent tasks thereby causing an accumulation of neuromuscular disturbance. In other words, muscle recruitment, spinal load and spinal stability during a given flexion task is influenced by previous tasks and will influence subsequent tasks. However, the role of work-task design on these disturbances remains unknown. Neuromuscular disturbance will be recorded by quantifying changes in: 1) trunk muscle co-contraction, 2) para spinal reflex response, 3) active trunk stiffness, 4) spinal load, and 5) spinal stability. An exposure-response relationship will be characterized in Specific Aim 1 to test the hypotheses that duration of static flexion is associated with progressive increases in neuromuscular disturbance and that task load increases the disturbance rate. We will quantify changes in co-contraction, stiffness, reflex, spinal load and stability recorded before and after periods of static trunk flexion by means of established methods and models. Specific Aim 2 will record neuromuscular behavior before and after exposure to flexion postures to test the hypothesis that flexion angle and exposure-rate influence the severity and rate of neuromuscular disturbance. Rate of recovery of neuromuscular behavior following static flexion tasks will also be recorded in Specific Aims 1 & 2 to gain insight into the effects of work-rest scheduling of flexion tasks. Specific Aims 3 and 4 will test the hypotheses that neuromuscular disturbance can accumulate across repeated static flexion tasks and repetitive dynamic lifting respectively. We will investigate how disturbance severity is influenced by flexion duration, peak flexion angle and lift rate. Finally, we will test the hypothesis that these disturbances can influence the dynamic control of spinal stability. The proposed study will investigate how workplace factors influence the severity and time-course of neuromuscular disturbance (including spinal load and stability). Results will guide future studies and/or epidemiologic investigations regarding the mechanism of cumulative risk from flexed working postures.

描述（申请人提供）：在弯曲的躯干姿势中工作会增加与职业相关的低背疾病的风险。这些姿势对脊柱组织施加菌株，从而导致躯干肌肉神经肌肉控制的暂时干扰。现有证据表明，暴露于弯曲姿势后，对脊柱生物力学有残留影响。从这些干扰中恢复可能是不完整的，因此开始了随后的任务，从而导致神经肌肉障碍的积累。换句话说，在给定的屈曲任务期间的肌肉募集，脊柱负荷和脊柱稳定性受到以前的任务的影响，并会影响后续任务。但是，工作任务设计对这些干扰的作用仍然未知。神经肌肉障碍将通过量化以下的变化来记录：1）躯干肌肉共抓取，2）para脊柱反射反应，3）主干刚度，4）脊柱载荷和5）脊柱稳定性。在特定目标1中将表征暴露 - 响应关系，以检验静态屈曲持续时间与神经肌肉干扰的逐步增加有关，并且任务负荷会增加干扰率。我们将通过已建立的方法和模型在静态躯干屈曲之前和之后记录的共接收，刚度，反射，脊柱载荷和稳定性的变化。特定的目标2将记录暴露于屈曲姿势之前和之后的神经肌肉行为，以检验屈曲角和暴露率影响神经肌肉障碍的严重程度和速率的假设。静态屈曲任务后的神经肌肉行为的恢复速率也将记录在特定的目标1和2中，以深入了解屈曲任务的工作及格计划的影响。具体目的3和4将测试神经肌肉干扰可以分别在重复的静态屈曲任务和重复动态升起的假设。我们将研究干扰严重程度如何受屈曲持续时间，峰屈曲角和提升速率的影响。最后，我们将检验以下假设：这些干扰可以影响脊柱稳定性的动态控制。拟议的研究将研究工作场所因素如何影响神经肌肉干扰的严重性和时间顺序（包括脊柱负荷和稳定性）。结果将指导未来的研究和/或流行病学研究，以了解弯曲工作姿势累积风险的机制。