Timing accuracy in human throwing
Timing accuracy in human throwing
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DOI：
10.1006/jtbi.1999.1024
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发表时间：
1999-12-21
影响因子：
2
通讯作者：
Challis, JH
中科院分区：
文献类型：
--
作者：
Chowdhary, AG;Challis, JH
这项研究检验了击中 6 或 8 m 外水平方向直径 20 cm 目标时肌肉激活和射弹释放所需的精确度。使用代表前臂和手加弹丸的肌肉驱动的两段模型来模拟仅限于矢状面的过臂投掷。定义模型肌肉和人体测量的参数特定于两名男性受试者。目标函数指定投掷必须既快速又准确。一旦找到最佳解决方案，就会研究这些时间的敏感性。激活或释放的时间被改变，模拟模型以新的时间重新运行，并确定射弹是否仍然击中目标。对于一组模拟，为了击中 8 m 处的目标，手腕激活开始和肘伸肌激活之间的时间延迟 [近远端 (PD) 延迟] 为 49 ms，释放时间为 83.4 ms，从而实现了最佳投掷。在解决方案空间的这个最佳点，启动窗口为 1.2 ms（假设原始 PD 延迟）。发射窗口是射弹必须发射并仍然击中目标的可用时间。腕屈肌可以被激活的窗口为 10.41 毫秒（假设弹丸在预先计划的最佳时间释放）。计时精度要求最低的控制方案的PD延迟为56 ms，释放时间为89.4 ms。该方案下激活和释放可能同时出现时序错误，PD延迟的时序窗口为4 ms，释放的时序窗口为2.4 ms。第二组模拟也发现了类似的结果。这些模拟揭示了快速准确投掷所需的肌肉激活和释放所需的精确时间。 (C) 1999 年学术出版社。
This study examines the precision required in the timing of muscle activations and projectile release to hit a target of 20 cm in diameter oriented horizontally either 6 or 8 m away. Over-arm throws, constrained to the sagittal plane, were simulated using a muscle-actuated, two-segment model representing the forearm and hand plus projectile. The parameters defining the modeled muscles and the anthropometry were specific to two male subjects. An objective function specified that throws must be both fast and accurate. Once an optimal solution had been found, the sensitivity of these timings was investigated. The times of activation or release were changed and the simulation model re-run with the new timings, and it was determined whether the projectile would still have struck the target. For one set of simulations, to hit the target at 8 m, the optimal throw was achieved with a time delay between the onset of wrist activation and elbow extensor activation [Proximal-distal (PD) delay] of 49 ms and a release time of 83.4 ms. At this optimal point in the solution space, the launch window was 1.2 ms (assuming the original PD delay). The launch window was the time available within which the projectile must be released and still strike the target. The window during which the wrist flexors could be activated was 10.41 ms (assuming the projectile was released at the pre-planned optimal time). The control scheme which required the least timing precision had a PD delay of 56 ms and a release time of 89.4 ms. Errors in timing could occur in activation and release simultaneously under this scheme, the timing windows were 4 ms in PD delay and 2.4 ms in release. Similar results were found for a second set of simulations. These simulations revealed the precise timings required in muscle activations and release required for fast accurate throws. (C) 1999 Academic Press.