Posterior pelvic tilt with heel lift

Lie on your back with knees bent and feet flat on the wall.
Draw in your lower abdominal and pelvic floor muscles. Tilt the pelvis backwards so that your lower back flattens into the floor.
Hold this position while you lift one of your heels off of the wall, and then return your foot flat against the wall.
Repeat the heel lift with your other foot.