The purpose of this study will be to investigate the effect of adding trunk integrated kinetic chain exercises to conventional exercise program on shoulder pain, function, isometric muscle strength, shoulder ROM and scapular orientation in patients with subacromial impingement syndrome.

Shoulder pain is the third most common musculoskeletal condition, affecting 67% of the general population . Shoulder impingement syndrome (SIS) is one of the most prevalent causes of shoulder pain, which is characterized by the compression of the rotator cuff and the subacromial bursa under subacromial space. Shoulder impingement syndrome is accounting for 44% to 65% of all shoulder complaints, with an estimated prevalence of 7% to 34%. In as many as 65% of SIS cases, shoulder pain is located in the anterolateral acromial region that may also spread to the lateral mid-humerus is the classic SIS symptom with a general decline in muscle strength.

New perspective for assessment and treatment of SIS is concentrating on movement-related mechanisms or biomechanical triggering factors. Exercises are effective at an early stage of SIS, which usually refers to stage I or early stage II according to Near's classification , such as training of the periscapular muscles (pectoralis minor, trapezius, serratus, and rhomboids) and strengthening of the rotator cuff (supraspinatus, infraspinatus, teres minor, and subscapularis), which acts as the shoulder joint stabilizers using concentric and eccentric exercises for the dynamic humeral centering effect and reduction of shoulder pain.). However, the best treatment strategy remains unknown If conservative treatment is failed operative treatment should be considered.

The scapula and glenohumeral joints are critical in allowing energy transfer from the trunk to lower limbs. According to Kibler et al, 1995, a 20% drop in kinetic energy transferred from the hip and trunk to the arm needs a 34% increase in shoulder rotational velocity to create the same amount of force to the hand. Deficiencies in the strength and mobility in these areas can have a negative impact on shoulder kinematics, increasing the risk of shoulder and elbow injury.

The defect at any link in the kinetic chain (Kc) will affect force transfer to subsequent segments and other components in the chain need to contribute more to compensate for the energy loss and this is explaining the risk factor for shoulder injury and pain. Recently, physical therapists typically recommend including lower extremity and trunk movements into shoulder rehabilitation protocols to maximize effective energy transfer throughout the entire KC. However, the importance of a KC approach over an isolated local shoulder treatment protocol during shoulder rehabilitation is not fully understood.

Previous studies investigated the efficacy of integrating the KC exercises into shoulder rehabilitation exercises and showed improvement of axio-scapular muscle recruitment, lower trapezius muscle ratios, and decrease the demands on the rotator cuff muscles.

A study examined EMG activity of the serratus anterior (SA) and lower trapezius (LT) during arm elevation this study and showed the highest activity of the SA, LT and Posterior Deltoid compared with the free-motion exercises. The quadruped shoulder flexion (QSF) is a form of KC ex in this study.

An EMG study analysis compared the muscle activation pattern of four Kc exercises to three conventional exercises the results showed that KC exercises resulted in the highest activation of all exercises. And this study is made on healthy subjects; if the examination is done on patients with shoulder pain the results may give different trends.

Furthermore, Yamauchi et al, (2015) investigated the effect of ipsilateral trunk rotation during shoulder exercises on the scapula. All Scaption, external rotations (ERs), and trunk rotation reported an increase of scapular ER or posterior tilt and LT activation. Retraction with 90° and 145° of shoulder abduction with trunk rotation considerably reduced UT activation and the UT/MT and UT/LT ratios. Therefore, the study findings imply that integrated trunk rotation KC ex adopted in this study may be useful in individuals with decreased (LT) activity and excessive (UT) activation or in cases where there is a diminished scapular ER or posterior tilt.

Inclusion Criteria:

• 1) Patients complaining of subacromial impingement syndrome . 2) Age 20-¬45 years old . 3) If they had at least three of the following 6 criteria: "Neer sign" positive, "Hawkins sign" positive, " Painful active shoulder elevation in scapular plane, painful rotary cuff tendon palpation," painful resisted isometric abduction " history of pain related to C5 dermatome.

  4) A 20 percent or higher score of SPADI (Shoulder Pain and Disability Index) baseline 5) Level of pain (at least 2/10 on VAS) 6) Patient with Body mass index (BMI) with 18 to 29.5 Kg/m2

Exclusion Criteria:

1. Prior history of cervical radiculopathy symptoms, frozen shoulder
2. Neurological disorders, inflammatory disorders
3. Complete RC tear and any previous surgery to the affected shoulder
4. Infections or tumors

single blinded