Dapena J
J Biomech. 1984;17(8):553-9. doi: 10.1016/0021-9290(84)90086-1.
Hammer speed at release is one of the most important factors contributing to the distance of a hammer throw. Hammer speed follows a generally increasing trend during the throw, with one fluctuation per turn. The purpose of the present paper was to quantify the influence of gravity on the speed fluctuations. Eight experienced hammer throwers were studied with three-dimensional filming methods. Instantaneous values of hammer velocity and speed were calculated from the film data. The rate of change of hammer speed due to the tangential component of gravity was computed, and integrated to calculate the accumulated contribution of gravity to hammer speed at all instants of the throw. These values were subtracted from the corresponding values of hammer speed. The amplitude of the fluctuations was reduced in the corrected speed functions, indicating a contribution of gravity to the original fluctuations. However, the fluctuations were still clearly present in the corrected speed functions, indicating the existence of other causal factors.
链球出手时的速度是影响链球投掷距离的最重要因素之一。在投掷过程中，链球速度总体呈上升趋势，每旋转一圈有一次波动。本文旨在量化重力对速度波动的影响。采用三维拍摄方法对八名经验丰富的链球运动员进行了研究。根据拍摄数据计算链球速度和速率的瞬时值。计算重力切向分量导致的链球速度变化率，并进行积分以计算重力在投掷全过程对链球速度的累积影响。从链球速度的相应值中减去这些值。在修正后的速度函数中，波动幅度减小，表明重力对原始波动有影响。然而，在修正后的速度函数中波动仍然明显存在，这表明存在其他因果因素。
