| الوصف: |
PURPOSE: Manual wheelchair (MWC) overhead activities are likely to cause shoulder injuries (Heyward et al., 2017). To understand their mechanisms, shoulder kinematics assessment is critical, but soft tissue artefacts around the scapula make it difficult. The scapula locator (SL) is a non-invasive reference tool for anatomical landmarks tracking (Van Andel et al., 2009). However, it is operated manually on movements of restricted volume and velocity. Technical cluster (TC) on the scapular spine combined with multi-body kinematics optimisation (MKO) is an alternate method for scapula tracking during any type of movement. Specific evaluation of this method for MWC propulsion, basketball shoot, and tennis serve, is required before its use on shoulder injury prevention. METHODS: 8 participants, with various levels of disabilities, performed a set of MWC propulsions on a ergometer, and simulated basketball shoots and tennis serves. Simultaneously, a SL was hold by an experimenter on 3 anatomical landmarks of the scapula. Location of reflective markers of the trunk, upper limbs, TC, and SL were recorded by a motion capture system. Thorax and scapula anatomical frames were built according to ISB recommendations (Wu, et al. 2005). Then, the scapula orientation was computed either from the TC, or the SL. Cardan angles with an y-x’-z” sequence was chosen. In combination to TC, a custom closed-chain model extended from (Seth et al. 2016) was used with MKO to avoid bone penetration, joint dislocation, and to minimize soft-tissue artefacts. RESULTS: Preliminary results on scapular kinematics from TC without MKO showed peak scapula misorientation of 5°, 9° and 12° during propulsion, basketball shoot, and tennis serve, respectively. Average misorientation angles affected mostly lateral/medial rotation. CONCLUSION: MKO with personalized clavicle length and a thorax ellipsoid surface contact is expected to reduce errors which would be beneficial, especially for overhead movements. |