Sub-acromial Impingement Syndrome (SIS) has been identified with a prevalence of almost 40% among shoulder pathologies. SIS has significant economic consequences owing to its treatment costs and losses incurred through workplace absenteeism.~Alterations in scapular muscle performance have been found in subjects with scapular dyskinesis. Hyperactivity of the upper trapezius (UT) with reduced middle (MT) and lower trapezius (LT) muscle activation in addition to insufficient serratus anterior (SA) muscle function have been related to decreased amounts of scapular upward rotation, external rotation, and posterior tilt in patients .~Research into scapular stability exercises for the management of SIS is increasing, yet there is little evidence on their efficacy .~The addition of scapular stabilization exercises to stretching and strengthening exercises can be significantly beneficial in increasing the strength, developing joint position sense and decreasing dyskinesia.~Proprioceptive neuromuscular facilitation (PNF) is a rehabilitation concept which is widely used by physical therapists , promoting motor learning, motor control, strength and mobility . This comprehensive rehabilitation approach includes task-oriented training with manual facilitation aimed at motor learning and motor control .~To the authors' knowledge, none of the studies has investigated the potential effect abnormal scapular muscle strengthening versus PNF exercise on the muscle strenth, muscle ratio, and ROM of the scapula during arm elevation in patient with SIS.
HYPOTHESES:~There will be no significant difference between scapular muscle strengthening and PNF exercise on improving muscle strength of upper trapezius in patients with shoulder impingement syndrome.~There will be no significant difference between scapular muscle strengthening and PNF exercise on improving muscle strength of middle trapezius in patients with shoulder impingement syndrome.~There will be no significant difference between scapular muscle strengthening and PNF exercise on improving muscle strength of lower trapezius in patients with shoulder impingement syndrome.~There will be no significant difference between scapular muscle strengthening and PNF exercise on improving muscle strength of serratus anterior in patients with shoulder impingement syndrome.~There will be no significant difference between scapular muscle strengthening and PNF exercise on muscle ratio of upper trapezius/lower trapezius muscles in patients with shoulder impingement syndrome.~There will be no significant difference between scapular muscle strengthening and PNF exercise on muscle ratio of upper trapezius/middle trapezius muscles in patients with shoulder impingement syndrome.~There will be no significant difference between scapular muscle strengthening and PNF exercise on muscle ratio of upper trapezius/serratus anterior muscles in patients with shoulder impingement syndrome.~There will be no significant difference between scapular muscle strengthening and PNF exercise on scapular symmetry at 0⁰ abduction in patients with shoulder impingement syndrome.~There will be no significant difference between scapular muscle strengthening and motor control exercise on scapular symmetry at 45⁰ abduction in patients with shoulder impingement syndrome.~There will be no significant difference between Scapular muscle strengthening and motor control exercise on scapular symmetry at 90⁰ abduction in patients with shoulder impingement syndrome.~There will be no significant difference between scapular muscle strengthening and PNF exercise on improving pain in patients with shoulder impingement syndrome.~There will be no significant difference between scapular muscle strengthening and PNF exercise on improving function in patients with shoulder impingement syndrome.