The McKenzie approach is a system of assessing and treating spinal and extremity pain syndromes through controlled movements and positioning. It aims to reduce pain through centralization of symptoms. There are three main syndromes - postural, dysfunction, and derangement. Postural syndrome involves pain from sustained positions, dysfunction from shortened tissues, and derangement from disrupted structures. Examination involves assessing posture, movements, and repeated movements to classify the syndrome. Treatment matches the syndrome and progresses forces from patient-generated to therapist-generated. Evidence supports McKenzie's classification system and eccentric exercises for tendonitis rehabilitation.