Shoulder Model Validation and Joint Contact Forces During Wheelchair Activities
By Morrow, Melissa M.B.; Kaufman, Kenton R.; An, Kai-Nan; Journal of Biomechanics, Volume 43, Number 13, pages 2487-2492Publication Date: September 17, 2010
Study validated an upper extremity musculoskeletal model and applied it to wheelchair activities for analysis of the estimated joint contact forces occurring at the shoulder. Study participants were 12 experienced manual wheelchair users aged 29 to 56 years who were without any current upper extremity injury. Upper extremity kinematics and handrim wheelchair kinetics were measured over three conditions: level propulsion, ramp propulsion, and weight relief lift. The experimental data were used as input to a subject-specific musculoskeletal model utilizing optimization to predict joint contact forces of the shoulder during all conditions. The model was validated using a mean absolute error calculation. Model results confirmed that ramp propulsion and weight relief lifts place the shoulder under significantly higher joint contact loading than level propulsion. In addition, they exhibit large superior contact forces that could contribute to impingement. This study highlights the potential impingement risk associated with both the ramp and weight relief lift activities. Level propulsion was shown to have a low relative risk of causing injury, but with consideration of the frequency with which propulsion is performed, this observation was not considered conclusive. Implications for further research are discussed.
Published by: Elsevier Inc. (Website:http://www.elsevier.com)
Link to text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2940839/?tool=pmcentrez
