Estimating Joint Impedance from the Surface EMG

从表面肌电图估计关节阻抗

• 批准号: 6802259
• 负责人: EDWARD A CLANCY
• 金额: $ 6.87万
• 依托单位: WORCESTER POLYTECHNIC INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-15 至 2006-09-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6802259
• 关键词: clinical research; elbow; electromyography; human subject; joints; mathematical model; muscle contraction; muscle rigidity; musculoskeletal system; occupational hazard; occupational health /safety; performance; posture; repetitive motion injury; work site

DESCRIPTION (provided by applicant): For a number of years, researchers have been studying the relationship between the surface electromyogram (EMG) and torque produced about a joint, as a means of non-invasively estimating musculoskeletal load in particular, and the dynamics of joint/musculoskeletal dynamics in general. Measurement and understanding of these dynamics is important in the prevention of musculoskeletal injuries in the workplace (e.g., injuries associated with heavy lifting jobs or repetitive tasks) and in rehabilitation engineering, neuromuscular disease, basic motor control research and other areas. A distinct aspect of load is the "rigidity" that we produce in order to achieve a task. For example, a worker using a power tool (e.g., a hand drill) will purposely co-contract his/her muscles to increase rigidity and stabilize the tool--often without producing any externally measurable torques/forces. However, excessive rigidity (concomitantly producing heavy internal musculoskeletal loads) may be associated with musculoskeletal injury. Currently, no robust methods exist for estimating the degree of rigidity while performing useful tasks. Formally, the mechanical engineering profession more properly defines "rigidity" as the static component of mechanical impedance. For constant-posture tasks (and other limited tasks), mechanical impedance has been measured, but the measurement requires imparting forces on the body, and thus disturbs the task under study. In this grant, we will propose relating mechanical impedance to EMG in a calibration task (in which the body is perturbed), so that after calibration, impedance might be estimated (from EMG) without perturbing the task. This paradigm is identical to EMG-torque modeling. Note that in performing EMG-torque modeling, one usually estimates EMG amplitude (EMGamp) from the EMG waveform, and then develops an EMGamp-torque model. Advanced methods for estimating EMGamp, now available in the literature, have been shown to provide better EMG-torque estimates. Our long-term objectives in this work are to use EMG-based estimates of mechanical impedance to study mechanisms of musculoskeletal injury in occupation tasks, as well as in other applications. Our specific aims are to (a) demonstrate that mechanical impedance about the elbow can be estimated from the EMG in a constant-posture, slowly force-varying task, and (b) demonstrate that advanced methods for estimating EMGamp lead to better EMG-impedance estimates.

描述（由申请人提供）：多年来，研究人员一直在研究表面肌电图（EMG）和关节产生的扭矩之间的关系，作为非侵入性估计肌肉骨骼负荷的一种手段，特别是关节/肌肉骨骼动力学的动力学。 测量和理解这些动态对于预防工作场所的肌肉骨骼损伤（例如与举重工作或重复性任务相关的损伤）以及康复工程、神经肌肉疾病、基础运动控制研究和其他领域非常重要。负载的一个独特方面是我们为了完成任务而产生的“刚性”。例如，使用电动工具（例如手钻）的工人会故意共同收缩他/她的肌肉以增加刚性并稳定工具——通常不会产生任何外部可测量的扭矩/力。然而，过度的刚性（同时产生沉重的内部肌肉骨骼负荷）可能与肌肉骨骼损伤有关。目前，不存在用于在执行有用任务时估计刚性程度的稳健方法。从形式上来说，机械工程专业更恰当地将“刚性”定义为机械阻抗的静态分量。 对于恒定姿势的任务（和其他有限的任务），已经测量了机械阻抗，但测量需要向身体施加力，从而干扰了正在研究的任务。在这笔拨款中，我们将建议在校准任务（其中身体受到干扰）中将机械阻抗与肌电图相关联，以便在校准后，可以在不干扰任务的情况下（根据肌电图）估计阻抗。该范例与 EMG 扭矩建模相同。请注意，在进行 EMG 扭矩建模时，通常从 EMG 波形估计 EMG 振幅 (EMGamp)，然后开发 EMG 扭矩模型。现在文献中提供的估计 EMGamp 的先进方法已被证明可以提供更好的 EMG 扭矩估计。我们这项工作的长期目标是使用基于肌电图的机械阻抗估计来研究职业任务以及其他应用中肌肉骨骼损伤的机制。我们的具体目标是 (a) 证明可以在恒定姿势、缓慢变化力的任务中根据 EMG 来估计肘部的机械阻抗，以及 (b) 证明用于估计 EMGamp 的先进方法可以带来更好的 EMG 阻抗估计。