The single-leg jump landing accounts for many non-contact ACL injuries in netball. Several factors place females at higher risk than males when performing this movement. Poor neuromuscular control and technique in particular exacerbate the external moments applied to the knee. A combination of high peak knee valgus moments (PKVM), flexion moments (FM) and internal rotation moments (IRM) can easily rupture the ACL. The Y-Balance Test (YBT), a quick and simple-to-administer screening tool, can be used to predict general lower extremity injuries through assessment of dynamic balance. This study explored the correlation between different knee moments during the forward single-leg jump landing (FSJL) and reach scores in the different YBT directions. It was hypothesized that further reach scores would correspond to lower knee moments. Twenty-one injury-free female national team netballers were recruited to perform randomly sequenced FSJL from maximal distance and YBT for the lower extremity. Three-dimensional motion analyses coupled with a force platform captured data modelled using the UWA lower limb model and marker set in order to identify knee joint moments during the weight-acceptance phase. Significant positive correlation was found between FM and posteromedial reach (r = 0.576, p = 0.006), and composite scores (r = 0.499, p = 0.021); while negative correlation was found between IRM and anterior reach (r = -0.452, p = 0.04). The findings suggest that reach scores are representative of knee joint moments during FSJL. This supports the hypothesis that the YBT could be an indicative screening tool for predicting non-contact ACL injury risk.
Keywords: non-contact acl injury, single-leg jump landing, knee joint moment, y-balance testBachelor of Science (Sport Science and Management
