Start on your hands and toes, with your hands directly under your shoulders.
Maintain a straight line from the top of your head to your heels.
Keep your arms straight, and drive the heels of your hands into the floor so that your shoulder blades flatten firmly against your upper back.
Your back should not round as you do this.
Hold this position for a moment.
Then relax your shoulder blades, letting your chest drop closer to the floor and then repeat.
Ensure you keep your arms straight throughout.
