Lie on your front with your toes on the floor.
Place your forearms on the floor and push up, lifting your torso and legs.
Hold a straight line from your shoulders to your feet for as long as you can, preventing the back from sagging.
Keep your buttocks squeezed and your hips level.
Holding this alignment, try to raise one straight leg off the floor.
Hold, then lower and repeat with the other leg.