The plank position is one of the best moves to tone the upper body and core, and this variation takes the intensity to a whole other you're-gonna-be-sore-for-days level. It's similar to the plank-to-tuck if you've ever used a TRX, but this move only requires two small towels.
- 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.
- After doing 10 reps, draw both knees to the right foot for five reps and then to the left foot for five.
- Repeat this 20-rep sequence two more times.