The influence of boot under surface on knee joint biomechanics and the risk of non-contact ACL injury in women's Rugby Union

Abstract

Boot under surface is considered to be one of most under-researched external mechanisms of Anterior Cruciate Ligament (ACL) injury in female rugby players. The aim of this study is to provide a more in depth understanding, of how different boot under surfaces effect knee joint biomechanics associated with non-contact ACL injury during cutting manoeuvres. Five active female students each performed five trails of a sidestep cut at both 45° and 60°, footwear was then changed from bladed boots to studs, and this process was repeated. A ten camera VICON motion analysis system, synchronised with a force platform, was used to determine the knee joint kinematics and ground reaction forces of each participant. The influence of boot type was not statistically significant on superior ground reaction force (GRF) values for both manoeuvres. However Blades significantly increase adduction GRF at 45° cutting angles only. External rotation, extension and valgus moments were found to be significantly higher when blades were worn, regardless of cutting angles. Blades compared with studs produced significantly lower flexion angles and lager valgus angles across both manoeuvres. Thus suggesting boot type does influence knee joint biomechanics, and that blades irrespective of cutting angle could potentially be more dangerous in terms of ACL injury risk.