Abstract
ACL injuries often occur when athletes perform cognitive tasks while performing a landing/cutting movement. This study investigated the effects of secondary cognitive tasks on hip and knee biomechanics during single limb landing. Sixteen recreational athletes (10 females and 6 males, age: 21.6 ± 2.5 years, mass: 65.2 ± 8.9 kg, height 1.66 ± 0.07 m) performed landings on their dominant limb as a single task and while simultaneously performing secondary cognitive tasks (mental arithmetic) provided through audio and visual means. Hip and knee joint angles and moments were calculated in all three planes of motion and analysed using statistical parametric mapping repeated-measures ANOVA. Hip adduction angle was significantly greater in audio and visual secondary task conditions compared to the single task condition during 88% to 100% of the landing period. Hip internal rotation was significantly greater in the visual secondary task condition compared to the single task condition during 68% to 92% of the landing period. There were no significant differences between task conditions for hip moments, knee moments or knee angles in all three planes of motion. These findings suggest secondary cognitive tasks, whether visual or audio, affect hip kinematics which may reflect reduced dynamic stability at the hip, contributing important further knowledge on the effect of secondary cognitive tasks during landing biomechanics.