You don't need disc sliders for this exercise; just grab a pair of towels and get to work.
- Begin in plank position with two towels under the balls of your feet (or paper plates if you're on carpet).
- Slowly bend both knees in toward the chest while keeping the arms straight, shoulders over the wrists, and maintaining a flat, tabletop back. If this is too difficult, draw one knee in at a time.
- This counts as one rep.
- For a variation, draw both knees to the right foot, straighten the legs back behind you, then draw both knees to the left foot.
- This counts as one rep.