Abstract
Abstract
To determine the most effective exercise for the supraspinatus, we measured T2 relaxation time (T2)for the rotator cuff and deltoid before and after three type of exercise ("empty can", "full can", "horizontal abduction in the prone position" ) on MRI. Six males performed three sets of each exercise with a weight of 20 repetitive maximum. Subjects were imaged before and immediately after the exercise. T2 for rotator cuff and deltoid on sagittal MR images were calculated using the software routines on the MRI system. An increase in T2 for the supraspinatus after the empty can and full can exercises (10.5±2.0,10.5±2.0 respectively) was significantly higher than that after the horizontal abduction (.63±1.3). There was no significant difference in the value for the supraspinatus between the empty can and full can exercises. This study has demonstrated that the horizontal abduction exercise is less effective for strengthening the supraspinatus than the empty can and full can exercises. We found no significant differences in loading of the supraspinatus between the empty can and full can exercises. Therefore, the full can exercise should be used for rehabilitation, because it involves less risk of pain provocation due to subacromial impingement.
