Generation of Linear Impulse During the Takeoff of the Long Jump

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, post-impact interval, and in total were measured using highspeed video (240 or 300 Hz) and a force plate (1200 Hz). Pearson correlations, Winsorized correlations, and the HC4 method were used to determine significant correlations between variables (α = 0.05). 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 impulse (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 post-impact 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.