Use it to replace: Captain's Chair Machine

How: Instead of curling up on the couch, sit upright to target your lower abs

Try: Couch Criss Crosses
Sit on the very edge of your couch and brace your core to maintain a straight, upright posture. Straighten your legs out in front of you and point your toes. Use your abs to cross your legs back and forth in a scissor motion for 60 seconds.