 Patients referred to the orthopedic unit for an arthroscopic subacromial decompression, are offered a three month rehabilitation program during the waiting time for surgery which is approximately 4-6 months. All patients must have tried conservative treatments for at least 6 months in primary care with unsatisfactory results. The patients will be randomized to either the structured eccentric exercises tutored by a physical therapist or control exercises with general movements for the neck and shoulders. All patients has an equal number of sessions with the PT to offer similar attention. After three months the following key-question has to be answered: due to your current experience of your shoulder problems do you still need this surgical intervention? A blinded orthopedic surgeon evaluates the following outcomes at baseline and after three and twelve months. Primary outcomes: Constant-Murley shoulder assessment, Disabilities of the Arm Shoulder and Hans and different aspects of pain. Secondary outcomes; EQ-5D, sick-leave and return to work. All patients are evaluated with a diagnostic ultrasound in order to reveal the condition of the rotator cuff. Also long-term results in those who go thorough with the surgery and those who decline will be assessed after 12 months. 