Timing of finger opening and ball release in fast and accurate overarm throws
Timing of finger opening and ball release in fast and accurate overarm throws
复制标题
快速准确的过臂投掷中手指张开和出球的时机
DOI：
10.1007/bf00231714
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发表时间：
2004
影响因子：
2
通讯作者：
B. Miller
中科院分区：
文献类型：
--
作者：
J. Hore;S. Watts;J. Martin;B. Miller
中枢神经系统如何精确地控制熟练动作中手指肌肉收缩的时间？对于过臂投掷，据计算，为了实现长距离投掷的准确性，需要小于 1 毫秒的球释放窗口。目的是研究仅使用手臂进行 100 次过臂投掷时球释放和手指张开的计时精度。受试者坐在固定的躯干上，在 1.5、3.0 和 4.5 m 处快速准确地向 6 cm 见方的目标投掷球。使用磁场搜索线圈技术以 1000 Hz 频率同时记录锁骨、上臂、前臂、手和中指远端指骨空间中的三维角位置。球的释放由中指近端和远端指骨上的压敏微型开关（近端和远端触发器）决定。球释放的可变性以释放时间平均值的标准偏差 (SD) 来定义，当与不同的手部运动参数同步时，球释放的可变性是不同的。它在运动开始时最高（当手开始绕空间固定的水平轴垂直向前和向上旋转时），并且在与手垂直时接近球释放的时刻同步时最低。这些值不取决于目标距离。当投掷与垂直手部位置同步时，并对 10 名受试者的 SD 进行平均，95% 的投掷 (4×SD) 的平均间隔为球释放 9.6 毫秒，手指张开开始为 10.0 毫秒。因此，两个独立的计时精度测量给出了相似的结果。结论是，对于男性休闲球运动员进行的 100 次快速准确的投球，手指张开和出球的时间得到了精确控制，但控制在不到一毫秒。
How precisely does the CNS control the timing of finger muscle contractions in skilled movements? For overarm throwing, it has been calculated that a ball release window of less than 1 ms is needed for accuracy in long throws. The objective was to investigate the timing precision of ball release and finger opening for 100 overarm throws made using only the arm. Subjects sat with a fixed trunk and threw balls fast and accurately at a 6-cm-square target when it was 1.5, 3.0 and 4.5 m away. Three-dimensional angular positions in space of the clavicle, upper arm, forearm, hand and distal phalanx of the middle finger were simultaneously recorded at 1000 Hz using the magnetic-field search-coil technique. Ball release was determined by pressure-sensitive microswitches on the proximal and distal phalanges of the middle finger (proximal and distal triggers). Variability of ball release, defined in terms of the standard deviation (SD) of the means of release times, was different when synchronized to different hand kinematic parameters. It was highest to the start of movement (when the hand started rotating vertically forward and up around a space-fixed horizontal axis) and was lowest when synchronized to the moment near ball release when the hand was vertical. These values did not depend on target distance. When throws were synchronized to vertical hand position, and SDs were averaged across the 10 subjects, the average interval for 95% of the throws (4×SD) was 9.6 ms for ball release and 10.0 ms for onset of finger opening. Thus, two independent measures of timing precision gave similar results. It is concluded that for 100 fast and accurate throws made by male recreational ball players, timing of finger opening and ball release was controlled precisely but not to fractions of a millisecond.
影响因子：
2.5
作者：
FETZ, EE;CHENEY, PD
通讯作者：
CHENEY, PD
影响因子：
56.9
作者：
BIZZI, E;MUSSAIVALDI, FA;GISZTER, S
通讯作者：
GISZTER, S