If you want a stronger core, add the plank into your routine. It's a classic move, and it will work your transverse abdominis (your true core muscles) like no other. Put your skills to the test with this 20-minute plank challenge.
- Start on the floor, resting on your forearms and knees.
- Step your feet out one at a time, coming into a plank position.
- Contract your abs to prevent your booty from sticking up or sinking. Your spine should be parallel to the floor, with your abs pulling toward the ceiling.