Lower Extremity Biomechanics During a Drop-Vertical Jump in Participants With or Without Chronic Ankle Instability

Abstract

<div class="section"> <a class="named-anchor" id="st1"> <!-- named anchor --> </a> <h5 class="section-title" id="d5434941e143">Context: </h5> <p id="d5434941e145">Chronic ankle instability (CAI) is a condition characterized by range-of-motion, neuromuscular, and postural-control deficits and subjective disability, reinjury, and posttraumatic osteoarthritis. Differences have been reported in kinematics, kinetics, surface electromyography (EMG), and ground reaction forces during functional tasks performed by those with CAI. These measures are often collected independently, and the research on collecting measures simultaneously during a movement task is limited. </p> </div><div class="section"> <a class="named-anchor" id="st2"> <!-- named anchor --> </a> <h5 class="section-title" id="d5434941e148">Objective: </h5> <p id="d5434941e150">To assess the kinematics and kinetics of the lower extremity, vertical ground reaction force (vGRF), and EMG of 4 shank muscles during a drop–vertical-jump (DVJ) task. </p> </div><div class="section"> <a class="named-anchor" id="st3"> <!-- named anchor --> </a> <h5 class="section-title" id="d5434941e153">Design: </h5> <p id="d5434941e155">Controlled laboratory study.</p> </div><div class="section"> <a class="named-anchor" id="st4"> <!-- named anchor --> </a> <h5 class="section-title" id="d5434941e158">Setting: </h5> <p id="d5434941e160">Motion-capture laboratory.</p> </div><div class="section"> <a class="named-anchor" id="st5"> <!-- named anchor --> </a> <h5 class="section-title" id="d5434941e163">Patients or Other Participants: </h5> <p id="d5434941e165">Forty-seven young, active adults in either the CAI (n = 24) or control (n = 23) group.</p> </div><div class="section"> <a class="named-anchor" id="st6"> <!-- named anchor --> </a> <h5 class="section-title" id="d5434941e168">Intervention(s): </h5> <p id="d5434941e170">Three-dimensional motion capture was performed using an electromagnetic motion-capture system. Lower extremity kinematics, frontal- and sagittal-plane kinetics, vGRF, and EMG of the shank musculature were collected while participants performed 10 DVJs. </p> </div><div class="section"> <a class="named-anchor" id="st7"> <!-- named anchor --> </a> <h5 class="section-title" id="d5434941e173">Main Outcome Measure(s): </h5> <p id="d5434941e175">Means and 90% confidence intervals were calculated for all measures from 100 milliseconds before to 200 milliseconds after force-plate contact. </p> </div><div class="section"> <a class="named-anchor" id="st8"> <!-- named anchor --> </a> <h5 class="section-title" id="d5434941e178">Results: </h5> <p id="d5434941e180">Patients with CAI had greater inversion from 107 to 200 milliseconds postcontact (difference = 4.01° ± 2.55°), smaller plantar-flexion kinematics from 11 to 71 milliseconds postcontact (difference = 5.33° ± 2.02°), greater ankle sagittal-plane kinetics from 11 to 77 milliseconds postcontact (difference = 0.17 ± 0.09 Nm/kg) and from 107 to 200 milliseconds postcontact (difference = 0.23 ± 0.03 Nm/kg), and smaller knee sagittal-plane kinematics from 95 to 200 milliseconds postcontact (difference = 8.23° ± 0.97°) than control participants after landing. The patients with CAI had greater vGRF from 94 to 98 milliseconds postcontact (difference = 0.83 ± 0.03 N/kg) and peroneal activity from 17 to 128 milliseconds postcontact (difference = 10.56 ± 4.52 N/kg) than the control participants. </p> </div><div class="section"> <a class="named-anchor" id="st9"> <!-- named anchor --> </a> <h5 class="section-title" id="d5434941e183">Conclusions: </h5> <p id="d5434941e185">Patients with CAI presented with differences in their landing strategies that may be related to continued instability. Kinematic and kinetic changes after ground contact and greater vGRF may be related to a faulty landing strategy. The DVJ task should be considered for rehabilitation protocols in these individuals. </p> </div>