The influence of eccentric hip abductor strength on knee valgus during a single leg drop landing in university netball players

Introduction: Anterior Cruciate Ligament (ACL) ruptures have accounted for 17.2% of Netball-related hospital admissions within the recent years. The main mechanism behind injury to the ACL has been shown to be from a valgus collapse of the knee during single limb landings. Hip strength, in particular, hip abductor strength has been seen to be an important factor related to knee valgus motion during functional movements. The aim of this study is to determine whether a weakness in eccentric hip abductor strength affects knee valgus during a single leg drop landing in University Netball players, placing them at a greater risk to ACL injury. Methods: Thirty female competitive university Netball players (Mean ± SD Age = 20 ± 2, Height = 166.02 ± 6.77cm, Mass = 63.34 ± 7.75kg) participated. Eccentric hip abductor torque (N.m/kg) was measured with the use of a Hand-Held Dynamometer (HHD). Knee varus/valgus angles were calculated from a kinematic analysis of initial and peak contact angles during a single leg drop landing. Results: A moderate, positive, significant correlation (r = 0.413, p = 0.023, p <0.05) was found between eccentric hip abductor torque (1.99 ± 0.30 Nm/kg) and knee varus/valgus angles (0.59 ± 6.56°) during the single leg landing (SLL). A strong, positive, significant correlation was found between initial contact and peak contact landing angles during the single leg landing (r=0.728, p<0.001, p