STARTING POSITION:
Find a bench with 30º of inclination. If is not, adjust the bench to get it. Place the back of the right knee at the top of the bench with your thigh resting on the backrest. Place the left foot on the floor as back as you can. Contract your pelvic floor and core while keeping your chest up.
MOVEMENT:
Slowly move your hips forward until you feel the stretch in your psoas muscle. Make sure you don't arch the back. Maintain the stretch during the required time and then do it with the other side.
TIPS: You should feel the stretch of the muscles but not pain.