MUSCLE OVEREXERTION DURING REPETITIVE LIFTING

重复举重过程中肌肉过度用力

• 批准号: 6192336
• 负责人: William Steven Marras
• 金额: $ 27.99万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-30 至 2004-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6192336
• 关键词: back injury; backache; biomechanics; clinical research; ergonomics; human subject; muscle stress; occupational hazard; occupational health /safety; repetitive motion injury; spinal disk injury

Occupationally-related low back disorders (LBDs) are the leading cause of lost workdays and the most costly occupational safety and health problem facing industry today. LBDs are particularly prevalent in manufacturing, distribution center, and warehousing environments where repetitive lifting is common. Although assessments have successfully evaluated LBD risk during a single exertion, none have been able to effectively assess how risk changes during repetitive lifting at various lifting frequencies throughout a workday. This study will assess how exposure to different frequencies of lift over time can result in unacceptable biomechanical risk of LBD. Our preliminary studies point to two mechanisms of risk. First, different lift frequencies affect lifting kinematics and the subsequent muscle recruitment patterns. These changes alter the nature (direction) and magnitude of spinal loading, thereby exceeding spine tolerance limits. Second, exposure to a repetitive lift throughout the workday can also result in muscle recruitment pattern changes over the work period, thereby, increasing the spinal loading throughout the day. Hence a lift frequency that is acceptable early in the workday may exceed biomechanical tolerance limits as the workday progresses. This study will explore the changes in muscle recruitment and spinal loading when workers lift one of three weights (corresponding to the range of industrial exposures) at six different lift rates over extended workdays. The frequency and duration of lift will be judged risky and unacceptable when the spinal loads exceed documented spine tolerance limits. These findings will result in an understanding of the portion of the population at risk for spine structure (disc) injury as a function of load magnitude, lifting frequency, and lift period duration. These results will provide quantitative guidance for the mediation of work-related LBDs for the millions of workers performing materials handling tasks in manufacturing and distribution center environments.

职业相关的腰背疾病 (LBD) 是造成工作日损失的主要原因，也是当今行业面临的代价最高的职业安全和健康问题。 LBD 在经常进行重复提升的制造、配送中心和仓储环境中尤其普遍。 尽管评估已成功评估单次运动期间的 LBD 风险，但没有人能够有效评估在整个工作日以不同举重频率重复举重期间风险如何变化。 这项研究将评估随着时间的推移，暴露于不同频率的提升会如何导致不可接受的 LBD 生物力学风险。 我们的初步研究指出了两种风险机制。 首先，不同的举重频率会影响举重运动学和随后的肌肉募集模式。 这些变化改变了脊柱负荷的性质（方向）和大小，从而超出了脊柱的耐受极限。 其次，在整个工作日中重复举重也会导致工作期间肌肉募集模式的变化，从而增加全天的脊柱负荷。 因此，随着工作日的进行，工作日初期可接受的举重频率可能会超过生物力学耐受极限。 本研究将探讨当工人在延长的工作日内以六种不同的举重速率举起三种重量之一（对应于工业暴露范围）时，肌肉募集和脊柱负荷的变化。 当脊柱负荷超过记录的脊柱耐受极限时，举升的频率和持续时间将被判定为有风险且不可接受。 这些发现将有助于了解有脊柱结构（椎间盘）损伤风险的人群比例与负荷大小、举重频率和举重持续时间的函数关系。 这些结果将为在制造和配送中心环境中执行物料搬运任务的数百万工人的工作相关 LBD 调解提供定量指导。