Start in a high plank position. One rep will be a transition back and forth between a high plank and a low plank by placing your right elbow on the floor, left elbow on the floor, right hand on the floor, left hand on the flow. Repeat in the opposite direction
Get into a high pushup position with your chest high and shoulder blades back. Engage your core by tilting your pelvis towards your belly button and hold. Rest in a table position with your knees on the floor between each rep.
Stand tall with your chest high and shoulder blades back. Put your arms straight out in front of you as if you were going to do a pushup. Tighten your abdominals, then, most importantly, tilt your pelvis upwards towards your belly button and hold.