This exercise is good to increase hip mobility due to arthritis or post total hip replacement surgery. Begin by stepping up onto a 2-3 inch stepper with the unaffected leg. In neutral tall posture, engage your inner core below the belly button by pulling the muscles in towards the spine. Next, with a straight knee bring the thigh into flexion and extension in a controlled pendulum movement. Repeat for 1 minute 6-8 times per day.