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The Effect of Arm Position on Lower Extremity Kinematics during a Single Limb Drop Landing: A Preliminary Study

Anterior cruciate ligament (ACL) injuries occur most commonly during non-contact situations, such as landing from a jump. Arm position has been shown to affect the loading of the lower extremity and therefore alter the potential injury risk. This study aimed to investigate the effect of arm position on lower extremity kinematics during single limb drop landings. Eight recreational American football players performed single limb drop landings on their preferential limb in four different conditions; (1) control (arms free); (2) arms to landing limb side; (3) arms in front of body; and (4) arms away from landing limb side. Kinematics of the hip, knee and ankle were recorded in both the sagittal and frontal planes at initial ground contact and maximum. Results showed that there was a significant decrease in maximum hip flexion and a significant increase in peak dorsiflexion when landing with arms away from the landing-side limb. Since decreased hip flexion and increased ankle dorsiflexion have been proposed to increase the likelihood of ACL injury, it would appear that landing with arms away from the landing-side limb may increase the risk of ACL injury, and therefore athletes should avoid this position when landing from a jump.