I have to credit last month’s Runners World for this killer core move!
Begin facedown on the floor, propped up on your forearms, with knees and feet together. With your elbows under your shoulders, lift your torso, legs, and hips in a straight line from head to heels. Hold for 10 seconds. Raise your right leg a few inches, keeping the rest of the body still. Lower and repeat with your left leg.
As you get stronger, increase the time to 20 seconds, then 30 seconds.
Now go run!