You probably already know and love the core-tightening power of the plank. But after countless sweaty holds, the honeymoon phase does fade. Need to spice things up? Just try these seven variations of the move straight from the Women's Health Big Book of Abs. Before you know it, you’ll be saying, ‘Oh, hey there, abs of steel.’

For even more moves, get the Women's Health Big Book of Abs today!

First, here's how to do a plank: Start to get in a pushup position, but bend your elbows and rest your weight on your forearms instead of on your hands. Your body should form a straight line from your shoulders to your ankles. Brace your core by contracting your abs as if you were about to be punched in the gut.

Get into plank position (a). Press your body up into the top position of a pushup by extending your arms one at a time (b). Pause (c), then reverse the movement and return to your elbows. That's 1 rep.

Start in plank position (a). Jump your feet out to the sides as if you were performing a jumping jack, making sure that your upper body doesn't rotate (b). Quickly return your feet to the starting position. That's 1 rep.

Start in plank position (a). Raise and straighten your right arm, and hold it so that it's parallel to the rest of your body (b). Lower to the starting position, then raise your other arm and repeat.

Begin in a plank position (a). Rotate to your left side and into a side plank (b). Hold for 10 seconds, then rotate into a right side plank and hold for another 10 seconds (c). That's 1 rep. Return to a plank position and repeat.

Lift your body into a side plank, and start with your right arm raised straight above you so that it's perpendicular to the floor (a). Reach under and behind your torso with your right hand, keeping your abs braced (b). Lift your arm back up to the starting position. That's 1 rep. Roll onto your other side, and repeat.

Start in a pushup position with your body straight from your shoulders to your ankles (a). Bring your right foot forward and place it next to your right hand (or as close as you can) (b). Try to prevent your hips from sagging or rising. Return your leg to the starting position and repeat with your left leg. That's 1 rep.

Place your forearms on a Swiss ball and your feet on a bench. Your body should form a straight line from your shoulders to your ankles. Brace your core by contracting your abs as if you were about to be punched. Work up to holding this position for 60 seconds.