Day 14: Take the “Killer Core” Challenge

A head turning six-pack isn’t the only reason to target the armada of muscles between your hips and chest. “A strong core will both allow you to transfer power more efficiently throughout your body and enhance your stability, boosting overall strength,” says Andy Speer, C.S.C.S., owner of Soho Strength Lab, in Manhattan. Challenge and strengthen your core at the same time with this three-move circuit: Hollow rock, plank side pulse, superman. “Do 10 reps of each exercise, moving from one to the next without rest,” says Speer. Once you finish all three exercises, begin the circuit again (no rest). “Try to do five circuits total, which will give you 50 reps for each move,” says Speer. Too easy? Double down, doing 20 reps per move per circuit. “50 total reps per move is attainable for many people,” says Speer, “but 100 is really tough, and demonstrates a high level of fitness.”

Hollow Rock: Lie face-up on the floor with your legs straight and your arms above your head. Contract your abs, lift your legs, head, and shoulder blades a few inches, and begin rocking forward and backward. Each “rock” is one rep.

Pulse side plank: Lie on your left side and prop your upper body on your left forearm. Raise your hips until your body forms a straight line from ankles to shoulders. Now lower and raise your hips. Each “pulse” equals one rep. Do 10 reps, switch sides, and repeat.
https://www.youtube.com/watch?v=IUZDm-2TfIE&rel=0&modestbranding=1
Superman: Lie facedown on the floor with your legs straight and your arms extended over your head. Squeeze your glutes, and raise your arms and legs off the floor. Pause, and then lower them. That’s one rep.
https://www.youtube.com/watch?v=xAGKvEiIv-g&rel=0&modestbranding=1

For more 31 Days of Fitness tips, check here for a new one every day in December.