1. Introduction
Rotator cuff injuries are one of the most common causes of shoulder pain especially in middle-aged and older adults. Different therapeutic approaches are used for these injuries. Intra-articular corticosteroid injection, anti-inflammatory modalities, physical therapy and exercise, and surgery are some of the conservative and invasive therapies in this pathology. Despite the effectiveness of these methods for pain relief in patients with rotator cuff injuries, there are some limitations for some of them. Weakness of rotator cuffs due to repeated steroid injections or the failure of surgery can cause some challenges in treatment. The evidence of the positive effect of exercise therapy in rotator cuff tendinopathy or tear is inconclusive. This study aims to evaluate the effect of a combined exercise protocol on improvement of patients with rotator cuff injuries.
2. Materials & Methods
This is a randomized clinical trial. The patients with shoulder pain lasting more than 6 weeks and aged 40-60 years were invited to attend the study. The inclusion criteria were: At least the results of three shoulder exam test (from among Neer’s test, Hawkins’s test, Empty Can, external and internal rotation resistance test, and speed test) be positive, existence of tendinopathy or tear in shoulder MRI, no complete rotator cuff tear, no radicular pain in the upper extremity, no frozen shoulder, and no other inflammatory diseases in shoulder. The patients who had received steroid injection or physical therapy in the last 3 months were excluded from the study. The eligible patients received 12 weeks of a combined exercise program at 4 phases.
Pain was measured by the Visual Analog Scale (VAS) and function was measured by two questionnaires: The Disabilities of the Arm, Shoulder And Hand (DASH), and Western Ontario Rotator Cuff Index (WORC). Range of motion (ROM) of shoulder joint was measured in five directions by a goniometer. All outcomes were evaluated before the intervention and 6, 12, 24 weeks after the intervention.
Ethical considerations: 
This study was registered by Iranian Registry of Clinical Trials (Code: IRCT20100718004409N13). The written informed consent was obtained from all participants prior to the study. 
3. Results 
Of 50 patients assessed for eligibility, 30 subjects met the criteria to enter the study. Of these, 6 patients were excluded due to follow up loss and lack of cooperation in performing the exercises. Finally, the data of 24 patients with rotator cuff tendinopathy and tear were analyzed. Their mean age was 51.5± 5.7 years and 23 (88.4 %) were females; 15(57.5) had injury in right shoulder; 14(53.8%) had supraspinatus tendinopathy, 6(23%) had supraspinatus tear, 3(12.5%) were with both supraspinatus and biceps tendinopathy, and one (4.16%) with both subscapularis and supraspinatus tendinopathy. 
As presented in Table 1, the pain score (VAS) decreased significantly from 8±0.1 at baseline to 3±0.1 in the 24th weeks after intervention (P< 0.001).


Shoulder ROM was also improved in the ranges of flexion, abduction, internal rotation, and external rotation in the 24th week after intervention which was statistically significant (P<0.001). The WORC score was increased from 46.5±3.4 before intervention to 78.2±3.4 in the 24th week after intervention (P<0.001). The DASH score was increased from 48.5±1.2 before intervention to 27.2±1.5 after 24 in the 24th week after intervention which was significant statistically (P<0.001). 
4. Discussion & Conclusion
The purpose of this study was to evaluate the effect of an exercise protocol on reducing the shoulder pain and improving the shoulder function of patients with rotator cuff tendinopathy and partial tear. The findings showed that a 12-week exercise protocol including strengthening, stretching, proprioceptive neuromuscular facilitation (PNF), and dynamic stabilization exercises was effective on pain reduction and improvement of shoulder function and shoulder joint ROM in the patients. The improvement of the variables lasted 6 months.
Rotator cuff injuries are very common at ages over 40 years. Their treatment is challenging. According to American Orthopaedic Association, there is no conclusive evidence of the positive effect of exercise on rotator cuff injuries. However, due to the limitations of other therapeutic approaches, scientists and clinicians have studied the effectiveness of exercise therapy as a complementary method in treating rotator cuff injuries. Choosing conservative therapy or surgery depends on the age, severity of injury, chronicity of injury, and activity level of patients. On the other hand, the high rate of surgery failure causes most patients to try other conservative treatments before the surgery specially in case of rotator cuff tendinopathy. 
The 12-week exercise therapy protocol (stretching, strengthening, PNF and dynamic stabilization exercises) can be used as a main or complementary approach for reducing shoulder pain or function in patients with rotator cuff injuries which has a lasting effect of 6 months. 

Ethical Considerations
Compliance with ethical guidelines
The design of this article has been registered in Iran's Clinical Trial system with code IRCT20100718004409N13. During this research, written consent was received from all patients to participate in the study.

Funding
This research did not receive any grant from funding agencies in the public, commercial, or non-profit sectors. 

Authors' contributions
Conceptualization and supervision: Parisa Nejati, Azar Moezy; Data collection: Hamid Reza Joneidi, Parisa Nejati; Data analysis: Ahmad Nazari, Hamid Reza Joneidi.

Conflicts of interest
The authors declared no conflict of interest.

Acknowledgement 
The authors thank the sports medicine department personnel of Rasool-e Akram Hospital in Tehran and the patients who participated in this study.


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