Physical therapy involves treatment to help patients recover mobility and function when unable to perform physical tasks due to injury or illness. It has evolved from practices in ancient Greece and became a modern profession in the late 19th century. Today, physical therapists require a bachelor's degree and master's in physical therapy including courses in science, biomechanics, and assessment techniques. They examine patients, develop treatment plans using exercises and other techniques, and work to help patients regain independence in clinics, hospitals, and other settings. Common reasons for physical therapy include strokes, arthritis, back pain, and injuries.