Effect of Landing Instructions and Dual-taskComponent on Landing Biomechanics in the Sagittal Plane during Drop Vertical Jumps among Individuals with and without Anterior Cruciate Ligament Reconstruction

Sammanfattning

After an anterior cruciate ligament reconstruction (ACLR) neuromuscular control is altereddue to disrupted proprioception. Landing instructions with external focus might facilitate abetter landing strategy in ACLR populations. Implementation of secondary cognitive tasksmight impact landing mechanics negatively. The purpose of this study was to examinedifferences in biomechanics of the lower extremity in the sagittal plane between a controland ACLR group during different drop vertical jump (DVJ) conditions with and withoutlanding instructions and a rapid decision-making cognitive task. Forty individuals (20 males,20 females, age 25.7 ± 5.5 years, time between ACLR to test 24.9 ± 16.1 months) (mean ±SD) who had undergone unilateral ACLR were recruited, together with a control group (20males, 20 females, age 22.0 ± 4.9 years). All subjects completed three different DVJconditions. Peak biomechanic values of the lower extremity in the sagittal plane wereextracted using force plates and 3D motion capture system during the first 100ms of landing.The ACLR group displayed lower kinematic values of the ankle (p=0.010), knee (p=0.012) andlower kinetic values of the knee (p=0.023) throughout all DVJ conditions. With a dual-taskcomponent, both groups exhibited increased hip flexion angle (p<0.001) and decreasedinternal knee extension moment (p<0.001). Landing instructions reduced internal kneeextension moment (p<0.001) in both groups. ACLR populations exhibit lower biomechanicalvalues of their injured leg compared to the matched limb in controls in the sagittal plane.Internal knee extension moments are positively impacted by landing instructions in bothgroups. A rapid decision-making cognitive task does not facilitate a dual-task cost during abilateral landing in either group.