A novel biomechanical injury risk score demonstrates correlation with lower limb posterior chain injury in fifty elite level rugby union athletes

ABSTRACT Objectives Lower limb posterior chain injury (PCI) is common amongst athletic populations, with multi-factorial risk factors including age, previous injury, strength measurements, range of motion and training load. Biomechanics are commonly considered in the prevention and rehabilitation of PCI by performance staff. However, there is no documented testing method to assess for associations between biomechanics and PCI. The aim of this study was to investigate whether there is an association between an easily applicable, novel biomechanical assessment tool and PCI. Methods Fifty male elite-level rugby union athletes (age 22.83±5.08) participating in the highest tier of England were tested at the start of the 2019 pre-season period and PCIs (N=48) were recorded over the 2019/20 playing season. Participants’ biomechanics were analysed using two-dimensional video analysis against an Injury Risk Score (IRS) system in the performance of the combined movement – prone hip extension and knee flexion. Participants’ biomechanics in carrying out this movement were scored against the 10-point IRS, where the more compensatory movement recorded sees an increase in an individual’s IRS. Participants’ IRS were then compared against the number of PCI sustained and Spearman’s correlation coefficient was utilised for analysis. Results There is a good significant association between IRS and PCI (R=0.573, p<0.001). Linear Regression demonstrated that an increase of 1 in IRS was associated with a 35% increase in PCI incidence (R 2 =0.346). Conclusion A good significance between the IRS and PCI provides preliminary support for its use as an injury risk assessment tool.