Insufficient scapular upward rotation is the primary movement impairment in this syndrome. The scapular position may be downwardly rotated, adducted, abducted, or normal.  This movement impairment may be evident at any point during the range of motion.  Muscle impairments include dominance, shortness, or stiffness of the downward rotator muscles [e.g., rhomboids, levator scapula, latissimus, pec minor/major] and insufficient activity of the upward rotators [e.g., serratus anterior, trapezius], (Sahrmann, 2004).