STARTING POSITION:
Sit on the floor and place a flat bench behind your back. Your shoulder blades should rest on the bench and your feet should spread at shoulder width apart, just in front of your hips. Place your arms on the bench. Contract your pelvic floor and core. Raise your left knee towards the roof.
MOVEMENT:
Using your right glute, fully extend your hips towards the roof while you exhale. Don't arch your back during the ascent. Return to the starting position in a smooth movement while you inhale. Repeat the movement for the specified amount of repetitions and then repeat with the other leg.
TIPS: The exercise key is quality over quantity. The trick is to perform the exercise using proper form.