Kinematic And Kinetic Differences Among Three Landing Tasks: Drop-jump, Sidestep, And Pivot

Abstract

Several tasks have been utilized to identify potential risk factors for Anterior Cruciate Ligament (ACL) injuries. Each task may place different demands on the joints; therefore it is relevant to understand the kinematic and kinetic differences among these tasks. PURPOSE: The purpose of this study was to determine kinematic and kinetic differences between a drop-jump (DJ), sidestep (SS), and pivot (PI) task. METHODS: 19 female collegiate soccer athletes (19.58±0.84years; 1.67±0.05m; 63.66±10.11kg) from a Division I institution participated in this study. 3D Motion analysis data were captured with a VICON system and Bertec force plates sampling at 500Hz. Three trials were collected for the DJ task, while 10 unanticipated trials were collected for the SS and PI, with a custom visualization software creating the unanticipated factor. Separate repeated measures analyses of variance were conducted for each dependent variable. Alpha level set at p<.05. Kinematic measured in degrees, and kinetic measured in multiples of body weight. RESULTS: There was a significant difference in ankle flexion (AF) at initial contact (IC) between tasks (SS=13±14>PI=2±13, SI>DJ=-8±13, PI>DJ, pPI=16±8, SS>DJ=17±6, pSI=-3±8, PI>DJ=-0.6±4, pDJ=38±10, p=.003). There was also a significant difference in maximum knee flexion (MKF) (DJ=83±10>SI=52±6, DJ>PI=50±15, pSI=57±16, DJ>PI=53±9, pSI=1.42±.27, DJ>PI=1.08±.48, and SS>PI, p<.001). CONCLUSIONS: The three tasks appear to have distinct kinematic and kinetic characteristics. DJ task had higher VGRF than the other two tasks, as well as higher MKF and MHF that may help in attenuating the increased landing forces. When conducting biomechanical studies to understand ACL injuries the tasks chosen should be sport specific. Funding Source: National Institutes of Health RO3: PA 04-002 NIAMS Small Grant Program for New Investigators: 1R03AR054031-01