Biomechanics and Motion Analysis Laboratory, Division of Orthopedic Research, Mayo Clinic, Rochester, MN 55906, USA.
J Biomech. 2010 Sep 17;43(13):2487-92. doi: 10.1016/j.jbiomech.2010.05.026. Epub 2010 Jun 8.
Chronic shoulder impingement is a common problem for manual wheelchair users. The loading associated with performing manual wheelchair activities of daily living is substantial and often at a high frequency. Musculoskeletal modeling and optimization techniques can be used to estimate the joint contact forces occurring at the shoulder to assess the soft tissue loading during an activity and to possibly identify activities and strategies that place manual wheelchair users at risk for shoulder injuries. The purpose of this study was to validate an upper extremity musculoskeletal model and apply the model to wheelchair activities for analysis of the estimated joint contact forces. Upper extremity kinematics and handrim wheelchair kinetics were measured over three conditions: level propulsion, ramp propulsion, and a 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 is not conclusive.
慢性肩部撞击症是手动轮椅使用者常见的问题。进行日常的手动轮椅活动所带来的负荷相当大，而且往往频率很高。肌肉骨骼建模和优化技术可用于估计肩部的关节接触力，以评估活动期间的软组织负荷，并可能确定使手动轮椅使用者面临肩部受伤风险的活动和策略。本研究的目的是验证上肢肌肉骨骼模型，并将该模型应用于轮椅活动，以分析估计的关节接触力。在上肢三个条件下测量了运动学和手轮动力学：水平推进、斜坡推进和减重抬升。将实验数据用作利用优化来预测所有条件下肩部关节接触力的特定于受试者的肌肉骨骼模型的输入。使用平均绝对误差计算验证了模型。模型结果证实，斜坡推进和减重抬升使肩部承受的关节接触负荷明显高于水平推进。此外，它们还表现出较大的上接触力，这可能导致撞击。本研究强调了斜坡和减重抬升活动与撞击风险相关。水平推进显示出造成伤害的相对风险较低，但考虑到推进的频率，这一观察结果并不确定。
