Come into plank position with your arms and legs straight, shoulders above the wrists.
Take a breath in, and as you exhale, bend your elbows out to the sides and lower your chest toward the ground. Stop as soon as your shoulders are in line with your elbows. Inhale to straighten the arms.
Maintaining a plank position, lift your left hand and tap your right shoulder. Place your left hand back on the ground. Repeat with the right hand. Keep your hip bones pointing towards the floor to prevent rotating your torso. This counts as one rep.
If this is too difficult, perform the push-up with your knees on the floor.