Kinematic model of wrist via marker placement during manual wheelchair propulsion

Due to the dynamic nature of MWP, motion analysis via markers placed on bony prominences provides the best approximation of the three dimensional trajectory of the segments of the upper extremity. Previous models which use motion analysis markers have been described in the literature, but these models have not corrected for positioning of the hand in a non-neutral position. The current model provides a standard method for determining the three ranges of motion commonly attributed to the wrist: flexion/extension, radial/ulnar deviation, and pronation/supination. These quantities are calculated via a local coordinate system based at the wrist as described by Shimada (1997), but applies a correction factor to account for non-neutral hand position during calibration.