Lie facedown on the floor and place one forearm over the other, resting your forehead on both. Next, roll your pelvis slightly under and pull your bas up and in toward your spine. First raise your right leg a few inches off the floor, and then your left, keeping them about 1 foot apart, with toes slightly pointed. Squeeze your glutes and lower-back muscles, and pulse both legs up and down a few inches for 20 counts. Rest for 20 seconds and then repeat for at total of three sets. To work your mid-back, bring your heels together and slightly bend your knees, and repeat for one more set of 20 pulses.