Utilizing a 10 camera Real-time Eagle Motion Analysis system, researches and physicians at Mayo Clinic worked with twelve individuals who were experienced manual wheelchair users, to determine the demands that manual wheelchair use places on the shoulders. Upper extremity kinematics and handrim wheelchair kinetics were measured over level propulsion, ramp propulsion, start and stop over level terrain, and a weight relief maneuver. Shoulder intersegmental forces and moments were calculated from inverse dynamics for all conditions.
There was a significant main effect of condition for the shoulder intersegmental forces in four of the six force directions: anterior (p=.001), posterior (p<.001), medial (p=.003), and superior (p<.001). There were no observed shoulder inferior forces during any of the conditions, so the direction was removed from the analysis. Post-hoc analysis indicated that in the ramp condition the anterior force was significantly higher than level, weight relief, start, and stop; and the posterior force of the ramp and weight relief conditions were significantly higher than level, start, and stop. Additionally, the weight relief medial force was significantly higher than level, start, and stop, but not different from ramp. The weight relief superior force was significantly higher than level, ramp, start, and stop. The level, start, and stop conditions were statistically equivalent for all force directions. There was no main effect of condition for the shoulder lateral force (p=0.334).
This study provides characterization of daily living and mobility activities associated with manual wheelchair propulsion not previously reported and identifies activities that result in higher shoulder kinetics when compared to standard level propulsion.
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