Single-leg drop landing movement strategies 6 months following first-time acute lateral ankle sprain injury.

No research exists predicating a link between acute ankle sprain injury-affiliated movement patterns and those of chronic ankle instability ( CAI) populations. The aim of the current study was to perform a biomechanical analysis of participants, 6 months after they sustained a first-time acute lateral ankle sprain ( LAS) injury to establish this link. Fifty-seven participants with a 6-month history of first-time LAS and 20 noninjured participants completed a single-leg drop landing task on both limbs. Three-dimensional kinematic (angular displacement) and sagittal plane kinetic (moment of force) data were acquired for the joints of the lower extremity, from 200 ms pre-initial contact ( IC) to 200 ms post- IC. Individual joint stiffnesses and the peak magnitude of the vertical component of the ground reaction force ( GRF) were also computed. LAS participants displayed increases in hip flexion and ankle inversion on their injured limb ( P < 0.05); this coincided with a reduction in the net flexion-extension moment at the hip joint, with an increase in its stiffness ( P < 0.05). There was no difference in the magnitude of the peak vertical GRF for either limb compared with controls. These results demonstrate that altered movement strategies persist in participants, 6 months following acute LAS, which may precipitate the onset of CAI. [ABSTRACT FROM AUTHOR]