手法を比較

	リアクティブストレングス指数	カウンター運動ジャンプ
分野	スポーツ科学	スポーツ科学
系統	Hypothesis test	Hypothesis test
提唱年	1987	1983
提唱者	Marteen Bobbert	Paavo Komi
種類	elastic response test	jumping test
原典	Bobbert, M. F., Huijing, P. A., & van Ingen Schenau, G. J. (1987). Drop jumping. II. The influence of dropping height on the biomechanics of takeoff after landing. Medicine & Science in Sports & Exercise, 19(4), 339-346.	Bosco, C., Luhtanen, P., & Komi, P. V. (1983). A simple method for measurement of mechanical power in jumping. European Journal of Applied Physiology, 50(2), 273-282.
別名	RSI, stretch-shortening cycle, elastic response	CMJ, jump height, explosive power
関連	3	3
概要	The reactive strength index (RSI) is a measure of lower-body reactive strength and elastic energy utilization, calculated as jump height divided by the contact time between landing from a drop and takeoff. Introduced by Bobbert and colleagues (1987), RSI quantifies the efficiency of the stretch-shortening cycle (SSC)—the ability to rapidly switch from eccentric (lengthening) to concentric (shortening) muscle contractions. High RSI indicates rapid, forceful engagement of muscles' elastic properties (tendons, contractile proteins) and is relevant in sports requiring rapid rebound (sprinting, jumping, rebounding). RSI is trainable and sensitive to plyometric training.	The counter-movement jump (CMJ) is a simple, field-friendly test of lower-body explosive power in which the athlete stands on a force plate, descends into a shallow squat (counter-movement phase), and explosively extends to jump as high as possible. Pioneered by Bosco and Komi (1983), the CMJ captures the integrated function of strength, rate of force development, and elastic energy utilization. Jump height (measured via flight time from force plate or motion capture) and peak power are reported. The CMJ is among the most widely used tests in sports science, athlete monitoring, and research due to simplicity, objectivity, and relevance to explosive power in nearly all sports.