Purpose: Activity restrictions are typically imposed on patients following median sternotomy. Among common sternal precautions (SP) are limitations in upper extremity (UE) force production. The purpose of this study was to measure peak forces during UE activities of daily living and to examine the effect of force production by varying the temporal components of task completion.
Methods: Fifteen participants between 22 and 59 years of age performed 19 lifting, pushing, or pulling tasks. For each task, participants performed 3 trials at their preferred speed and 3 trials at a slow speed. Peak forces were measured using a digital dynamometer. Mean percentage change in force produced during preferred and slow movements was recorded for each task. Descriptive statistics were calculated, and paired Student t tests were used to determine differences in force between preferred and slow speeds.
Results: Mean peak force generated during preferred speed was less than 10 pounds (a common SP weight limit) for only 6 of the 19 tasks. Peak force exceeded 20 pounds for 5 tasks. Forces were less for all tasks performed at a slow speed as compared with a preferred speed, except 1; the percentage reduction in force ranged from 8% to 61%.
Conclusions: Many daily tasks generate UE peak forces in excess of 10 pounds. Performing UE movements at slower than normal speeds reduces peak forces. Optimally, SP should be individualized and functionally based, with consideration for the UE forces produced during activities patients are likely to perform.