Most studies of high-speed lower body movements include practice repetitions for facilitating consistency between the trials. We investigated whether 20 repetitions of drop landing (from a 30.5-cm platform onto a force plate) could improve consistency in maximum ground reaction force, linear lower body stiffness, depth of landing, and jump height in 20 healthy, young adults. Coefficient of variation was the construct for variability used to compare the first to the last five repetitions for each variable. We found that the practice had the greatest effect on maximum ground reaction force (p = .017), and had smaller and similar effects on lower body stiffness and depth of landing (p values = .074 and .044, respectively), and no measurable effect on jump height. These findings suggest that the effect of practice on drop landing differs depending upon the variable measure and that 20 repetitions significantly improve consistency in ground reaction force.

中文翻译：

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练习对健康，年轻成年人降落飞行性能的内部影响。

大多数关于高速下半身运动的研究都包括重复练习，以促进试验之间的一致性。我们调查了20次重复降落降落（从30.5厘米平台降落到测力板上）是否可以提高20名健康的年轻人的最大地面反作用力，线性下半身刚度，降落深度和跳跃高度的一致性。变异系数是变异性的构造，用于比较每个变量的前五个重复与最后五个重复。我们发现，这种做法对最大地面反作用力影响最大（p = .017），对下半身的刚度和着陆深度影响较小且类似（分别为p值= .074和.044），对跳跃高度的可测量影响。