This study is warranted in order to evaluate if an earlier reported positive effect on shoulder function and pain with the specific exercise strategy, in patients on waiting list for subacromial decompression, can be repeated in the primary care population of patients with subacromial pain. There is no consensus about first-line exercises for patients with subacromial pain, and these positive results on pain and shoulder function need to be reproduced in primary care before they can be recommended and implemented. Further, knowledge about which factors that can be used in prediction rules for patients that will respond to the exercises or needs surgery is lacking.