Lie on your back with both knees bent and your feet flat on the floor.
Tighten your buttock muscles and lift your hips up off the floor.
Aim for a straight line from your shoulders to your knees.
Hold this position and lift one leg by straightening your knee.
Make sure you keep your hips up and level throughout this movement.
Slowly lower your leg, then bring your buttocks back down to the floor.
Repeat the exercise lifting the other leg.