Low back pain is commonly reported in occupational settings due to factors such as heavy lifting and poor ergonomic practices, often resulting in significant healthcare expenses and lowered productivity. Assessment tools for human motion and ergonomic risk at the workplace are still limited. Therefore, this study aimed to assess lower back muscle and joint reaction forces in laboratory conditions using wearable inertial measurement units (IMUs) during weight lifting, a frequently high-risk workplace task. Ten able-bodied participants were instructed to lift a 28 lbs. box while surface electromyography sensors, IMUs, and a camera-based motion capture system recorded their muscle activity and body motion. The data recorded by IMUs and motion capture system were used to estimate lower back muscle and joint reaction forces via musculoskeletal modeling. Lower back muscle patterns matched well with electromyography recordings. The normalized mean absolute differences between muscle forces estimated based on measurements of IMUs and cameras were less than 25 %, and the statistical parametric mapping results indicated no significant difference between the forces estimated by both systems. However, abrupt changes in motion, such as lifting initiation, led to significant differences (p < 0.05) between the muscle forces. Furthermore, the maximum L5-S1 joint reaction force estimated using IMU data was significantly lower (p < 0.05) than those estimated by cameras during weight lifting and lowering. The study showed how kinematic errors from IMUs propagated through the musculoskeletal model and affected the estimations of muscle forces and joint reaction forces. Our findings showed the potential of IMUs for in-field ergonomic risk evaluations.

中文翻译：

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使用可穿戴 IMU 估算举重任务中的下背部肌肉力量

由于提重物和不良的人体工学实践等因素，在职业环境中经常会出现腰痛，这通常会导致巨额医疗费用和生产力下降。用于工作场所人体运动和人体工程学风险的评估工具仍然有限。因此，本研究旨在在举重（一项经常存在的高风险工作场所任务）期间使用可穿戴惯性测量单元 (IMU) 评估实验室条件下的下背部肌肉和关节反作用力。十名身体健全的参与者被要求举起 28 磅的重物。盒子上的表面肌电图传感器、IMU 和基于摄像头的运动捕捉系统记录了他们的肌肉活动和身体运动。 IMU 和运动捕捉系统记录的数据用于通过肌肉骨骼建模来估计下背部肌肉和关节反作用力。下背部肌肉模式与肌电图记录非常匹配。基于 IMU 和相机测量估计的肌肉力之间的归一化平均绝对差异小于 25%，统计参数映射结果表明两个系统估计的力之间没有显着差异。然而，运动的突然变化（例如开始举重）会导致肌肉力量之间存在显着差异（p < 0.05）。此外，在举重和下降过程中，使用 IMU 数据估计的最大 L5-S1 关节反作用力明显低于摄像机估计的最大 L5-S1 关节反作用力 (p < 0.05)。该研究展示了 IMU 的运动误差如何通过肌肉骨骼模型传播并影响肌肉力和关节反作用力的估计。我们的研究结果表明了 IMU 在现场人体工程学风险评估方面的潜力。