Spoiler: If you're doing them wrong (which, sorry, you probably are), you're barely working your abs.

You can crunch, plank, and leg lift all you want-but if you're not doing these moves correctly (and pairing them with a healthy lifestyle), you probably aren't going to see ab progress anytime soon. (And for the record, core strength is important for a lot more reasons than getting a six-pack.)

Leg lifts are a pretty basic-but effective-core exercise. But it's easy to mess them up. (Ditto with biceps curls.) That's why Jen Widerstrom (Shape's consulting fitness director and the creator of the 40-Day Crush-Your-Goals Challenge) is sharing the most common leg lift mistakes and how to do a perfect leg lift, so you can optimize your abs routine instead of wasting time in the gym. Watch her demo the correct and incorrect version in the video above, then give it a try yourself in this 10-minute at-home abs workout.

The key mistake is arching your lower back, which lets your ab muscles slack off and puts more pressure on your hip flexors and back extensor muscles to control and perform the movement. Before you toss your legs around, find a solid position lying faceup with your arms overhead and legs extended, and really press your lower back into the floor. (This is called a hollow body hold; watch Bob Harper demo it here.) Once you can hold that for 15 seconds with your back pressed firmly into the floor, try the leg lift with Jen's tips.

How to Perform the Perfect Leg Lift


  • Press lower back into the floor. While lowering legs, stop once you feel your back lifting off the floor.
  • Keep legs together and inner thighs engaged.
  • Inhale on the way down, exhale on the way up.


  • Allow lower back to arch off the floor.
  • Let legs come apart.
  • Hold your breath.