(1) Background: The aim of the study was to determine the post-activation performance enhancement (PAPE) of vertical and horizontal ground reaction force parameters during jumps and change of direction following flywheel squat exercise using two different flywheel inertias. (2) Methods: Eleven male athletes performed a countermovement jump (CMJ), standing broad jump (SBJ), and “modified 505” change of direction (COD) in a control condition and 6 minutes following three sets of six repetitions of flywheel half squats at one of two inertias (0.029 kg·m² and 0.061 kg·m²). Peak directional ground reaction force, power, and rate of force development were calculated for each test. (3) Results: Higher inertia flywheel squats were able to acutely enhance CMJ peak vertical force (Bayes Factor (BF₁₀) = 33.5, very strong; δ = 1.66; CI: 0.67, 2.70), whereas lower inertia flywheel squats were able to acutely enhance CMJ peak vertical power (BF₁₀ = 3.65, moderate; δ = 0.93; CI: 0.11, 1.88). The vertical squat exercise induced no PAPE effect on resultant SBJ or horizontal COD ground reaction force parameters, nor were any differences observed between the inertias. (4) Conclusions: Researchers and practitioners should consider the kinetic and kinematic correspondence of a pre-load stimulus to the subsequent sport-specific activity (i.e., flywheel squat to CMJ).

中文翻译：

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跳跃和方向变化过程中垂直和水平地面反作用力参数的飞轮后蹲增强

（1）背景：该研究的目的是使用两个不同的飞轮惯性来确定飞轮下蹲运动后跳跃和方向变化期间垂直和水平地面反作用力参数的激活后性能增强（PAPE）。（2）方法：11名男运动员在控制条件下进行了反向运动跳跃（CMJ），站立跳远跳跃（SBJ）和“修改的505”方向改变（COD），并在三组飞轮重复六次之后进行了6分钟以两种惯性之一（0.029 kg·m ²和0.061 kg·m ²）。每次测试都计算了峰值定向地面反作用力，功率和力的发展速率。（3）结果：较高惯性的飞轮蹲起能够急剧增强CMJ峰值垂直力（贝叶斯因子（BF ₁₀）= 33.5，非常强；δ= 1.66； CI：0.67、2.70），而较低惯性的飞轮蹲起能够急剧增强CMJ峰值垂直功率（BF ₁₀ = 3.65，中等; δ= 0.93；CI：0.11、1.88）。垂直下蹲运动不会对合成的SBJ或水平COD地面反作用力参数产生PAPE效应，在惯性之间也没有观察到任何差异。（4）结论：研究人员和从业人员应考虑预负荷刺激与随后的运动特定活动（即，向CMJ飞轮下蹲）的动力学和运动学对应关系。