It has been shown that jump height is increased by 10% or more and take-off velocity is increased by 6-10% when using arms compared: Health Science Report, UCC, Ireland

It has been shown that jump height is increased by 10% or more and take-off velocity is increased by 6-10% when using arms compared to jumps without the use of arms (Harman et al., 1990; Lees et al., 2006; Shetty and Etnyre, 1989; Luhtanen and Komi, 1979). Although a marked difference has been shown repeatedly between the two conditions, there is not a comprehensive theory outlining the mechanisms behind these discrepancies.

There are three proposed theories behind this phenomenon. The earliest theory was the ‘transmission of force’ theory (Payne et al., 1968). This theory proposes that when the arms accelerate upwards, a downward force acts upon the body, which in turn, creates a greater ground reaction force and greater impulse.

The result of this is a greater vertical velocity of the center of mass, which has been shown to contribute between 60% (Feltner et al., 1999) and 72% (Lees et al., 2004) to the increase in jump height. The findings by Payne et al. (1968) have been challenged, as the starting positions of jumps are different. Later research (Feltner et al., 2004; Lees et al., 2004) suggested that increased impulse is due to an increased duration of the propulsion phase in arm-swing jumps. This implies a more complex mechanism is involved.

The second prominent theory behind the benefits of arm swing, the ‘joint torque augmentation’ theory (Feltner et al., 1999), suggests that arm swing generates a downward force at the shoulder on the rest of the body during the propulsion phase, which causes the lower limb joints to slow the rate of extension which enables them to produce greater muscle torque production and greater muscle forces (Harman et al., 1990; Feltner et al., 1999).

Lees et al. (2004) dismissed this theory, as the effect of greater joint torques, and lower angular velocities do not result in greater power generation in vertical jumps. Ashby and Delp (2008) countered this argument and proposed that power was not a valid measure and work should be the variable measured. The final theory is the ‘pull’ theory, suggested by Harman et al. (1990), where the arms start to decelerate near take off which leads to the net upward force of the shoulder acting to pull the trunk upwards, increasing the amount of energy in the rest of the body.

This theory was supported by Lees et al. (2004), but a more recent simulation (Cheng et al., 2008) found that the arms pull for a shorter amount of time than first reported. Despite marked interest in the topic, the difference between countermovement jumps with and without arm swing requires further investigation.