本研究的目的是要探討:(1)比較優秀垂直跳表現組與一般組間，在垂直 跳地面反作用力的峰值、斜率、積分值上，是否有差異存在;(2)比較優秀組與一 般組間，在垂直跳各期之作用肌與拮抗肌的肌電最大值、絕對積分值，以及作用 肌與拮抗肌的比值上，是否有差異存在，並以此找出優秀垂直跳表現者作用於地 面的力量及肌肉使用的模式，提供改進跳躍技術的參考。受試者為12名大專學 生，將其區分為垂直跳表現優秀組(70公分以上)與一般組(55公分以下)，分別以 測力板與肌電儀測量垂直跳時地面反作用力與作用肌(股直肌、腓腸肌)、拮抗肌 (股二頭肌、脛骨前肌)肌電的訊號，並進行三次的重覆測試。結果顯示優秀組在 地面反作用力的峰值和斜率上均顯著大於一般組，而在下蹲預備期的股直肌肌 電，以及跳躍作用期股二頭肌肌電、作用肌與拮抗肌肌電的比值，優秀組亦顯著 大於一般組。由此可以推論，如果要有好的跳躍表現，除了要有作用肌強壯的向 心收縮力量外，拮抗肌亦要能有強壯的離心收縮力量，如此才能增加作用於地面 的力量及速度，提高身體離地時的衝量。

　　　　　In order to find the optimal mode of vertical jump performance, the purposes of this studywere to determine the difference of reaction force and the EMG in vertical jump between eliteathletes and normal subjects. Three repetitive trial in vertical jump of six elite subjects (verticaljump performance above 70 cm) and six normal ones (vertical jump performance below 55cm) were evaluated. Use Kistler force platform system to measure the reaction force andBiopac System to measure the electromyogram (EMG) of agonist muscle (M. rectus femoris& M. gastrocnemius) and antagonist muscle ( M. biceps femoris & M. tibialis anterior). Itshowed that the peak and slope of reaction force in elite subjects were significantly greaterthan normal ones. In the same way, the maximum and integrated EMG activity of M. rectusfemoris in squat phase, M. biceps femoris in jump phase, and the ratio of agonist-antagonistmuscle in elite subjects were also significantly greater than normal ones. Thus, we areconfident that elite vertical jump performance should be bases on either the powerfulconcentric contraction of agonist muscle or the powerful eccentric contraction of antagonistmuscle, then the force and speed could be increased.