While exercises like sit-ups and crunches work the rectus abdominis, or "six-pack" muscles, this simple-looking exercise ...

This simple yet powerful stability exercise activates deep core muscles, protects your spine, and builds real functional strength without crunches.

If you're a fan of Pilates classes, this move will be familiar to you. And if not, don't worry! It's as easy to learn as it is to do, and I promise your abs will thank you. According to the experts at ...