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Generation of Linear Impulse During the Takeoff of the Long Jump

Christopher D. Ramos, Melvin Ramey, Rand R. Wilcox, and Jill L. McNitt-Gray

This study investigates the effect of initial leg angle on horizontal jump performance. Eleven highly skilled male and female long jumpers (national and Olympic level) performed a series of horizontal jumps for distance. Within-jumper differences in initial leg angle, normalized horizontal and net vertical impulses, contact time, and average reaction force during the impact interval, postimpact interval, and in total were measured using high-speed video (240 or 300 Hz) and a force plate (1200 Hz). Pearson’s correlations, Winsorized correlations, and the HC4 method were used to determine significant correlations between variables (α = .05). Within-jumper analysis indicated that when jumpers initiate the takeoff phase with a larger leg angle they are able to generate significantly greater negative horizontal and positive net vertical impulses (n = 7). Increased impulse generation was the result of increased contact time (n = 5 of 7) and/or increased average reaction force (n = 4) during the impact interval (n = 3) and/or postimpact interval (n = 4), depending on the individual. Initial leg configuration at contact and individual specific impulse generation strategies are important to consider when determining how an athlete with initial momentum can increase impulse generation to jump for distance.