Background: Patients often need to use their arms to assist with functional activities, but frequently after heart surgery performed via median sternotomy upper extremity pushing is limited to <10 lb to help minimize force across the healing sternum. The main purposes of this study were to determine if during functional mobility older patients less accurately estimated using <10 lb of arm force than younger ones and if they were able to improve their accuracy following feedback training to the same degree as younger patients.
Methods: Force was measured using an instrumented walker and pectoralis major muscle recruitment was measured using electromyography (EMG). Functional mobility tasks included walker ambulation and sit-stand transfers. After baseline testing, subjects (n=65) completed a brief session of visual and auditory concurrent feedback training. Left and right arm data were averaged and the improvement with feedback training was calculated as the absolute difference between pre- and post-data. Statistical analyses included 2-way ANOVA and t-Tests (P<0.05).
Findings: Results showed that before feedback training mean arm force was >10 lb during all functional mobility tasks for both groups. We found significant differences in arm force and EMG between groups (young vs old) and trials (pre- vs post-feedback training). We found significantly greater improvement (change) in arm force in the older compared to younger subjects.
We also found a significantly greater reduction EMG activity in the older subjects than younger subjects for all tasks except during stand-to-sit trials.
Conclusions: Patients, particularly older ones, may not be able to accurately estimate arm force used during weight bearing activities and visual and auditory feedback may improve accuracy and also modulation of pectoralis major muscle activation. Results suggest that an instrumented walker and feedback training could be clinically useful for patients recovering from not only from open heart surgery but also lower extremity surgeries/trauma.
Keywords: Sternal precautions, median sternotomy, feedback training, functional mobility, walker ambulation, open heart surgery