摘要
Purpose： The purpose of this study was to develop and validate a method that would facilitate immediate feedback on linear hammer speed during training. Methods： Three-dimensional hammer head positional data were measured and used to calculate linear speed （calculated speed） and cable force. These data were used to develop two linear regression models （shifted and non-shifted） that would allow prediction of hammer speed from measured cable force data （predicted speed）. The accuracy of the two models was assessed by comparing the predicted and calculated speeds. Averages of the coefficient of multiple correlation （CMC） and the root mean square （RMS） of the difference between the predicted and calculated speeds for each throw of each participant were used to assess the level of accuracy of the predicted speeds. Results： Both regression models had high CMC values （0.96 and 0.97） and relatively low RMS values （1.27 m/s and 1.05 m/s） for the non-shifted and shifted models, respectively. In addition, the average percentage differences between the predicted and calculated speeds were 6.6% and 4.7% for the non-shifted and shifted models, respectively. The RMS differences between release speeds attained via the two regression models and those attained via three-dimensional positional data were also computed. The RMS differences between the predicted and calculated release speeds were 0.69 m/s and 0.46 m/s for the non-shifted and shifted models, respectively. Conclusion： This study successfully derived and validated a method that allows prediction of linear hammer speed from directly measured cable force data. Two linear regression models were developed and it was found that either model would be capable of predicting accurate speeds. However, data predicted using the shifted regression model were more accurate.
目的:本研究旨在开发和验证一种在训练中能协助快速反馈链球线速度的方法。方法:通过测量链球顶部三维位置数据,计算链球的线速度和锁链作用力。用这些数据建立两种线性回归模型,并利用链锁作用力预测链球速度:一种模型采用通过调控的数据建立模型,使速度和作用力的最大值和最小值一致(移位模型);另一种模型的数据则未经过调控(非移位模型)。用这两种模型并通过直接测量锁链作用力预测链球球速。通过比较预测的和通过链球的位置数据测得的链球速度,评估模型的准确性。收集每人每次投掷球速的预测值与计算值,计算其差值的多元相关系数(CMC)和均方根(RMS)的平均值,以此来评估预测值的准确性。结果:两种模型均呈现出较高的CMC(0.96和0.97)和相对较低的RMS值(1 27 m/s和1.05 m/s)。此外,球速预测值与测量值的平均百分比差异在非移位和移位组中分别为6 6%和4.7%。同时通过两种模型及三维定位数据计算链球出手速度的均方根差值。非位移模型和位移模型中,预测值和计算值的均方根差值分别为0.69 m/s和0.46 m/s。结论:本研究成功推导并验证一种能够从直接测得的链锁作用力预测链球速度的有效方法。开发的两种线性回归模型都能预测速度,但使用移位模型更加准确。
