Characteristics of vertical drop jump to screen the anterior cruciate ligament injury

To clarify the characteristics of vertical drop jump (VDJ) for screening athletes at high risk of ACL injury by comparing the kinematic, kinetic and electromyographic variables of different VDJ.

Thirty male soccer players were recruited to measure parameters of knee kinematics, kinetics, and surface electromyograph during VDJ in four kinds of movements measured (the distance between the take-off feet is 5 cm or 30 cm, and the distance between the landing feet is 5 cm or 30 cm) using the Vicon motion capture system, Kistler3-D dynamometer, and Noraxon surface electromyograph test system.

The peak knee abduction moment was significantly greater for landing feet distance of 30 cm compared to landing feet distance of 5 cm, regardless of whether the distance between take-off feet was 5 cm (0.58 vs. 0.44) or 30 cm (0.61 vs. 0.40); regardless of whether the distance between landing feet was 5 cm (22.78 vs. 20.45) or 30 cm (24.32 vs. 21.87), the peak vertical Ground Reaction Force was significantly increased for the take-off feet distance was 5 cm compared to take-off feet of 30 cm.

In the test of VDJ, athletes will adopt different landing strategies for different movement instructions, and the VDJ with the distance of 5 cm between the take-off feet and the distance of 30 cm between the landing feet may be the better maneuver to screen for risk of ACL injury.