Related Data for: Between-limb asymmetry in kinetic and temporal characteristics during bilateral plyometric drop jumps from different heights

This study investigated the between-limb asymmetry in kinetic and temporal characteristics during bilateral plyometric drop jumps from different heights. Seventeen male basketball players performed drop jumps from 3 heights on two platforms in randomized orders. Vertical ground reaction force data were analysed with respect to the lead limb (i.e. the limb stepping off the raised platform first) and trail limb. Peak forces and loading rates of each limb were calculated. The absolute time differential between the two limbs at initial ground contact and takeoff were determined. The frequency of symmetrical landing and taking off with “both limbs together” were counted using 3 time windows. Results showed that the lead limb displayed higher peak forces and loading rates than the trail limb across all heights (p <.05). As drop height increased, the absolute time differentials decreased at initial ground contact (p <.001) but increased at takeoff (p =.035). The greater the preset time window, the more landings and takeoffs were classified as bilaterally symmetrical. In conclusion, higher drop heights allowed subjects to become more bilaterally symmetrical in the timing of landing but this reduction in temporal asymmetry did not accompany with any reduction in kinetic asymmetry.

本研究探究了不同高度下双侧肢体在跳落式增强式跳跃（plyometric drop jumps）过程中的动力学与时间特征不对称性。17名男性篮球运动员在两台升高平台上以随机顺序完成3种高度的跳落式增强式跳跃。以前置肢体（即最先脱离升高平台的肢体）与后置肢体为分析对象，对垂直地面反作用力（vertical ground reaction force）数据进行处理分析，计算两侧肢体的峰值力与负荷率，并测定二者在初次触地与离地时刻的绝对时间差；同时采用3种时间窗（time window）统计双侧肢体同步触地与同步离地的发生频率。结果显示，在所有测试高度下，前置肢体的峰值力与负荷率均显著高于后置肢体（p < 0.05）。随着跳落高度升高，初次触地时刻的绝对时间差显著缩小（p < 0.001），但离地时刻的绝对时间差则显著增大（p = 0.035）；预设时间窗越长，被归类为双侧同步的触地与离地动作占比越高。综上，更高的跳落高度可使受试者在触地时序上的双侧对称性提升，但这种时间不对称性的降低并未伴随动力学不对称性的同步减弱。