The contribution of arm swing to vertical jumping height
King, Stephen G.
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This study compared the height of a vertical jump attempted with and without arm swing. Countermovement jumps from the floor and depth jumps from 25 and 75 cm were performed. Nine male and six female subjects, 20 through 26 years old, who had high school experience in sports that involved explosive movements, such as basketball and volleyball, performed the jumps. High-speed filming was conducted at 99 Hz and the projected images of the jumps were digitized using a 21-point, 14-segment model and software developed at the Northern Illinois University Biomechanics Laboratory. This model incorporated the segmental end-point data derived from Clauser, McConville and Young's data. Dependent, two-tailed t tests were used to analyze the kinematic data. The dependent variable was the vertical displacement of the center of gravity for a particular jump. The independent variable was the type of arm motion. In a countermovement jump, in which the hips, knees and ankles flexed prior to take off, a gain of 25% in vertical displacement was seen when the arms were swung. In the depth jumps from 25 and 75 cm, the arm swing enabled the subjects to jump 18 and 20% higher. It was thought that the subjects jumped higher after swinging their arms because their bodies produced more total energy that may have been applied to the floor vertically downward to assist in takeoff. The conclusion was that arm swing can contribute up to a 25% gain in jump height. The major implication is that researchers investigating depth jumping must consider the contribution of the arms to jumping performance when designing depth-jump studies.