Stand behind a chair (in case you need it to help you balance), and cross your right leg over your left, making sure the right and left feet end up side by side.
Keeping your core engaged, exhale and slowly bend forward. Drop your hips back and keep your legs straight, with just a slight bend in that front knee.
Stop when you feel the stretch and hold for 20 seconds. As you slowly return to standing, remember to keep squeezing your abs.
Repeat on the opposite side, crossing the left foot over the right. Do this stretch twice on each side.