Associations Between Constrained and Unconstrained Approaches to Cutting Manoeuvres and the Increased Risk of Anterior Cruciate Ligament Injury.

Abstract

Many sports such as hockey, lacrosse and tennis use equipment such as sticks or rackets. This equipment can be a constraint on movements such as cutting at angles or sidestepping. There is a lack of clarity into how technique is adapted and whether this adaptation increases the potential for injury at the ACL. The aim of this research was to develop understanding of whether there are any kinetic and kinematic adaptations to cutting manoeuvres with constrained and unconstrained conditions in the sport of hockey. Furthermore, to see whether these adaptations to a constraint causes any subsequent possibility for an increased risk of injury at the knee. Eight fully healthy, male hockey players (mean ± SD: age 19.5 ± 1.5 yr; height 181.6 ± 7.4 cm; mass 83.7 ± 21.3 kg) were used in this study. All ten participants performed three different tasks; two control runs; four 45° cuts to the left and four 45° cuts to the right. Each cutting task was carried out four times by each subject (two holding a stick and two without) resulting in them carrying out ten trials each. A four-camera Cartesian Optoelectronic Dynamic Anthropometer motion analysis system was used to obtain three-dimensional (3D) kinematic coordinate data at 50Hz. In addition to this a Kistler 9287BA force plate was synchronized with CODA and collected kinematic ground reaction force profiles for each subject at 2000Hz. The main findings of this study were that (a) the cutting tasks produced greater peak forces when a stick was carried, (b) significant differences were found for min/max differences between constrained and unconstrained for produced greater peak forces when a stick was carried, (b) significant differences were found for min/max differences between constrained and unconstrained for flexion/extension and internal/external rotations, (c) varus/valgus created the greater angle difference when both the constrained tasks were performed. As such it is recommended that training should be adapted to allow players a chance to get used to performing the movements whilst carrying their sticks.