Many athletic endeavors require specific and propulsive motions. While performing the standing broad jump, the forceful arm swing aids in the body's trajectory in the sagittal plane (Robertson and Fleming, 1987). In contrast, a broad jump without an arm swing may possibly decrease the maximum horizontal displacement as well as the vertical height. Disabled athletes without arms must rely on compensatory movements from the trunk and hip regions. This is interesting because many times arm movement gives an athlete added momentum during the execution of a skill. Weber and Cafarelli (1973) concluded that performance of a broad jump depended partially on body size and the muscular strength involving forceful action of the upper body. However, very little research exists on doing broad jumps without arm swings.
In this study, we examined the biomechanics of broad jumps with and without a propulsive arm swing to determine whether or not the propulsive arm motion contributed to the overall height and distance of the jump. Furthermore, we will look at how the trunk segment, hip and knee joint will compensate for the sagittal plane force of the arms when they are not in use. We predict that the arm swing is a significant factor propelling the body in a forward motion. Furthermore, trunk segment compensation will not completely make up for the height and distance generated by the arm swing.