Come into a plank position with your feet resting on the edge of the coffee table or couch, or if you have neither, just use the floor.
Draw your navel toward your spine to engage your abs, which will help keep your spine straight and your body stabilized.
Lift your right leg into the air, then slowly lower it back toward the bed, but don't let it touch. This counts as one repetition. Keep your pelvis level throughout your reps.
Complete 10 reps with the right leg, then 10 with the left.