Breast cancer survivors have known scapular kinematic alterations that may be related to the development of secondary morbidities. A measure of muscle activation would help understand the mechanisms behind potential harmful kinematics. The purpose of this study was to define muscle force strategies in breast cancer survivors. Shoulder muscle forces during 6 functional tasks were predicted for 25 breast cancer survivors (divided by impingement pain) and 25 controls using a modified Shoulder Loading Analysis Module. Maximum forces for each muscle were calculated, and 1-way analysis of variance (P < .05) was used to identify group differences. The differences between maximum predicted forces and maximum electromyography were compared with repeated-measures analysis of variance (P < .05) to evaluate the success of the model predictions. Average differences between force predictions and electromyography ranged from 7.3% to 31.6% but were within the range of previously accepted differences. Impingement related pain in breast cancer survivors is associated with increased force of select shoulder muscles. Both pectoralis major heads, upper trapezius, and supraspinatus peak forces were higher in the pain group across all tasks. These force prediction differences are also associated with potentially harmful kinematic strategies, providing a direction for possible rehabilitation strategies.

乳腺癌幸存者已知肩胛骨运动学改变可能与继发性疾病的发生有关。肌肉激活的测量将有助于了解潜在有害运动学背后的机制。本研究的目的是确定乳腺癌幸存者的肌肉力量策略。使用改进的肩部负荷分析模块预测了 25 名乳腺癌幸存者（除以撞击疼痛）和 25 名对照者在 6 项功能任务期间的肩部肌肉力量。计算每块肌肉的最大力，并使用单向方差分析 ( P < .05) 来识别组间差异。将最大预测力和最大肌电图之间的差异与重复测量方差分析 ( P < .05) 进行比较，以评估模型预测的成功程度。力预测和肌电图之间的平均差异在 7.3% 到 31.6% 之间，但在之前可接受的差异范围内。乳腺癌幸存者的撞击相关疼痛与特定肩部肌肉力量的增加有关。在所有任务中，疼痛组的胸大肌、上斜方肌和冈上肌峰值力均较高。这些力预测差异还与潜在有害的运动学策略相关，为可能的康复策略提供了方向。