Wrbaskić N, Dowling J J
Department of Kinesiology, McMaster University, 1280 Main Street West, Hamilton, Ont., Canada L8S 4K1.
J Electromyogr Kinesiol. 2006 Feb;16(1):32-41. doi: 10.1016/j.jelekin.2004.09.005. Epub 2005 Oct 10.
The purpose of this study was to determine the mechanisms responsible for improving ballistic elbow extension. In doing so, an electromyography (EMG)-driven model was developed to predict the actual triceps torque so that the model parameters between subjects could be compared. Thirty-two subjects performed maximum isometric trials at 60 degrees , 90 degrees and 120 degrees of elbow extension to determine torque-angle relations. Dynamic elbow extension trials were then performed against relative loads of 0%, 20%, 40%, 60% and 80% and absolute loads of 1.1 and 2.2 kg. These trials were used to determine the torque-angular velocity relation for each subject. The model predicted the triceps torque during the unloaded, 1.1 and 2.2 kg trials with an average r = 0.964 and an average root mean square error of 4.34 Nm. As a result of the good predictions, a forward dynamics approach was used to substitute different neuro-muscular mechanisms of a poor performance with those from an individual that displayed a superior performance. Performance was shown to improve when these modifications were made. Therefore, the EMG-driven model was capable of modeling the actual muscle torque which allowed for the identification of areas of weakness of a poor performance. A prescription for improvement was identified, albeit artificially, on an individual basis. The next stage is to determine which specific interventions can accomplish those theoretically proposed.
本研究的目的是确定改善弹道式伸肘的机制。在此过程中，开发了一种肌电图（EMG）驱动模型来预测肱三头肌的实际扭矩，以便比较不同受试者之间的模型参数。32名受试者在肘关节伸展60度、90度和120度时进行最大等长试验，以确定扭矩-角度关系。然后针对0%、20%、40%、60%和80%的相对负荷以及1.1千克和2.2千克的绝对负荷进行动态伸肘试验。这些试验用于确定每个受试者的扭矩-角速度关系。该模型在无负荷、1.1千克和2.2千克试验中预测肱三头肌扭矩，平均r = 0.964，平均均方根误差为4.34牛米。由于预测效果良好，采用了前向动力学方法，用表现优异个体的神经肌肉机制替代表现较差个体的不同神经肌肉机制。进行这些修改后，表现得到了改善。因此，EMG驱动模型能够模拟实际肌肉扭矩，从而识别表现较差个体的薄弱环节。尽管是人为地，但在个体基础上确定了改进方案。下一阶段是确定哪些具体干预措施能够实现那些理论上提出的目标。
