BACKGROUND & OBJECTIVE
A battery of functional testing including jumping and hopping tasks have been widely accepted as criteria for assessing functional performance prior to return to sport (RTS) after an anterior cruciate ligament reconstruction (ACLR). The ultimate goal of these performance measures is to achieve symmetry between limbs (i.e. symmetrical jumping height or distance); however, passing this criterion does not always guarantee successful RTS or a reduction in future re-injuries. Therefore, this study aimed to identify biomechanical and performance variables between ACLR and non-ACLR limbs across commonly used jump tests in individuals 9 months post-surgery.
Eligible participants included male athletes with primary ACLR, who participated in a multidirectional field sport and wanted to return to their pre-injury level. Testing took place approximately 9 months after surgery in a 3D biomechanics laboratory. An eight-camera motion analysis system was used to capture motion at the lower limbs, pelvis and trunk, and two force plates were used to assess ground reaction forces. Jump testing consisted of the double leg drop jump (DLDJ), single leg drop jump (SLDJ), single leg hop for distance (SLHD) and the hurdle hop (HH). Jump height, jump length, reactive strength index (RSI) and centre of mass (COM) were used as performance variables.
156 male athletes (mean age 24.8 years; 8.8 months post-surgery) were recruited. Consistent across all jumps were differences in internal knee valgus moment, knee internal rotation angle, and ankle external rotation moment between the ACLR and non-ACLR limb. The DLDJ