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板球击球中前脚蹬地的运动学与动力学

Kinematics and kinetics of the drive off the front foot in cricket batting.

作者信息

Stretch R, Buys F, Du Toit E, Viljoen G

机构信息

Sport Bureau, University of Port Elizabeth, South Africa.

出版信息

J Sports Sci. 1998 Nov;16(8):711-20. doi: 10.1080/026404198366344.

Abstract

A cinematographic analysis of the drive off the front foot (D) and the forward defensive stroke (FD) was undertaken to establish the kinematic and kinetic factors involved in playing these strokes against medium-fast bowling. Fourteen provincial cricket batsmen were filmed at 100 Hz while batting on a turf pitch with a specially instrumented bat. Results for the drive off the front foot revealed that the movement and stroke pattern were generally supportive of the coaching literature, with the forward defensive stroke forming the basis of the drive. Certain mechanical differences, although non-significant, were evident to facilitate the attacking nature of the front foot drive and included a higher backlift (FD = 0.65 m; D = 0.74 m), later commencement of the stride (FD = 0.64 s pre-impact; D = 0.58 s pre-impact) and downswing of the bat (FD = 0.38 s pre-impact; D = 0.36 s pre-impact), a shorter front foot stride (FD = 0.72 m; D = 0.68 m) with the front foot placement taking place later (FD = 0.14 s pre-impact; D = 0.06 s pre-impact), and the back foot dragging further forward at impact (FD = 0.05 m; D = 0.10 m). The front upper limb moved as a multi-segmental series of levers, which resulted in the drive showing significantly greater (P< 0.05) peak bat horizontal velocity at 0.02 s pre-impact (FD = 3.53 +/- 3.44 m s(-1); D = 11.8 +/- 4.61 m x s(-1)) and 0.02 s post-impact (FD = 2.73 +/- 2.88 m x s(-1); D = 11.3 +/- 4.21 m x s(-1)). The drive showed a significantly greater (P < 0.05) bat-ball closing horizontal velocity (FD = 24.2 +/- 4.65 m x s(-1); D = 32.3 +/- 5.06 m x s(-1)) and post-impact ball horizontal velocity (FD = 6.85 +/- 5.12 m x s(-1); D = 19.5 +/- 2.13 m x s(-1)) than for the forward defensive stroke. The point of bat-ball contact showed nonsignificant differences, but occurred further behind the front ankle (FD = 0.09 +/- 0.17 m; D = 0.20 +/- 0.13 m), with the bat more vertical at impact (FD = 62.6 +/- 6.53 degrees ; D = 77.8 +/- 7.05 degrees). Significant differences (P< 0.01) occurred between the grip forces of the top and bottom hands for the two strokes, with the principal kinetic finding that the top hand plays the dominant role during the execution of the drive with the bottom hand reinforcing it at impact. Similar grip force patterns for the two strokes occurred during the initial part of the stroke, with the drive recording significantly greater (P < 0.05) forces at 0.02 s pre-impact (top hand: FD = 129 +/- 41.6 N; D = 199 +/- 40.9 N; bottom hand: FD = 52.2 +/- 16.9 N; D = 91.8 +/- 41.1 N), at impact (top hand: FD = 124 +/- 29.3 N; D = 158 +/- 56.2 N; bottom hand: FD = 67.1 +/- 21.5 N; D = 86.2 +/- 58.2 N) and 0.02 s post-impact (top hand: FD = 111 +/- 22.2 N; D = 126 +/- 28.5 N; bottom hand: FD = 65.5 +/- 26.9 N; D = 82.4 +/- 28.6 N).

摘要

对前脚击球(D)和向前防守击球(FD)进行了影片分析,以确定在面对中速投球时打出这些击球动作所涉及的运动学和动力学因素。14名省级板球击球手在草皮球场上使用特制的仪器化球棒击球时,以100赫兹的频率进行拍摄。前脚击球的结果显示,其动作和击球模式总体上与教练文献相符,向前防守击球构成了前脚击球的基础。虽然一些机械差异不显著,但明显有助于前脚击球的攻击性,包括更高的引棒高度(FD = 0.65米;D = 0.74米)、更晚开始的跨步(FD = 击球前0.64秒;D = 击球前0.58秒)和球棒下摆(FD = 击球前0.38秒;D = 击球前0.36秒)、前脚跨步更短(FD = 0.72米;D = 0.68米)且前脚落地更晚(FD = 击球前0.14秒;D = 击球前0.06秒),以及后脚在击球时向前拖动得更远(FD = 0.05米;D = 0.10米)。前上肢作为多节段的杠杆系列运动,这使得前脚击球在击球前0.02秒(FD = 3.53±3.44米/秒;D = 11.8±4.61米/秒)和击球后0.02秒(FD = 2.73±2.88米/秒;D = 11.3±4.21米/秒)显示出显著更高(P<0.05)的球棒水平峰值速度。前脚击球比向前防守击球显示出显著更高(P < 0.05)的球棒 - 球闭合水平速度(FD = 24.2±4.65米/秒;D = 32.3±5.06米/秒)和击球后球的水平速度(FD = 6.85±5.12米/秒;D = 19.5±2.13米/秒)。球棒与球的接触点差异不显著,但发生在前脚踝后方更远的位置(FD = 0.09±0.17米;D = 0.20±0.13米),击球时球棒更垂直(FD = 62.6±6.53度;D = 77.8±7.05度)。两种击球动作的上下手握力存在显著差异(P<0.01),主要的动力学发现是,在上手击球过程中,上手起主导作用,下手在击球时起到加强作用。两种击球动作在击球初始阶段握力模式相似,前脚击球在击球前0.02秒(上手:FD = 129±41.6牛;D = 199±40.9牛;下手:FD = 52.2±16.9牛;D = 91.8±41.1牛)、击球时(上手:FD = 124±29.3牛;D = 158±56.2牛;下手:FD = 67.1±21.5牛;D = 86.2±58.2牛)和击球后0.02秒(上手:FD = 111±22.2牛;D = 126±28.5牛;下手:FD = 65.5±26.9牛;D = 82.4±28.6牛)记录到显著更大(P < 0.05)的力。

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