Not only do traditional crunches target just one of your main core muscles, but after a few minutes of the repetitive motion, that muscle fatigues and other areas (like your hip flexors and neck) take over to compensate. “The exercises below are better–they activate your abdominal wall from all angles, targeting your entire core in fewer moves,” says Michele Olson, Ph.D., a professor of exercise science at Auburn University at Montgomery.
Do it: Starting with the first exercise, complete the given number of reps, then immediately continue to the next move. Repeat until you’ve finished the entire workout.
Move 1: Stability-Ball Rollout
Kneel in front of a stability ball with your knees hip-width apart and your forearms on the ball (a). With a flat back, brace your core and slowly roll the ball forward as far as you can without dropping your hips (b). Pause, then bend your elbows to roll the ball back to start. That’s one rep. Do 10.
Move 2: Stability-Ball Pike
Start with your shins on top of the ball, arms straight, hands shoulder-width apart on the floor (a). Brace your abs and keep your legs straight as you raise your hips toward the ceiling, drawing the ball toward you (b). Pause, then slowly roll back to start That’s one rep. Do 10.
Move 3: Lying Leg Extension
Lie on your back with your knees and hips bent to 90 degrees, hands outside your shins and shoulders lifted off the floor (a). Straighten your legs in front of you and bring your arms back next to your ears (b) Pause, then reverse the move. That’s one rep. Do 10.
Move 4: Rotating Side Plank
Start in plank position (a). Rotate your body and roll onto your left forearm, stacking your right foot on top of your left in a left side plank (b). Hold for one or two seconds, then return to start; pause, then repeat on the other side. Alternate sides for 30 seconds.