If you're not feeling challenged by regular planks, this moving plank variation should surely wake up your core.
- Start in a low plank position, but instead of pressing your palms into the floor, clasp your hands together.
- Without moving anything else in your body, slowly shift forward on your toes to slide your shoulders a few inches forward, so they're no longer above your elbows.
- Then shift backward on your toes to slide your shoulders back, so they're just behind your elbows.
- That's one rep. Do three sets of 10 reps, resting for 30 seconds to one minute between sets.