Lower limb symmetry cannot be assumed when investigating the biomechanics of a stop-jump landing: Implications for experimental design

Despite the fact that landing tasks often involve dual-limb motion, researchers investigating lower limb landing biomechanics often assume movement symmetry. However, whether lower limb symmetry can be assumed when investigating dynamic, sport-specific movements such as the stop-jump, has not been investigated. Therefore, this study aimed to determine whether there were any significant differences in the peak anterior cruciate ligament force (FACL) generated and the lower limb kinematics displayed by the dominant limb compared to the non-dominant limb of participants during a stop-jump task. Sixteen healthy male athletes performed 5 successful trials of a stop-jump movement. During each trial, the participants' ground reaction forces and three-dimensional kinematics were recorded for both lower limbs. Although lower limb symmetry was apparent for most of the biomechanical variables characterizing landing technique during the stop-jump, significantly higher FACL and significantly less knee flexion were evident for the dominant compared to the non-dominant limb. It is recommended that researchers clearly identify their primary outcome variables, and ensure that their experimental design accounts for any possible effect of limb dominance.