How to Do Leg Raises for Strong, Sculpted Lower Abs

Even if you've done hundreds of crunches and held planks for what feels like weeks, you might not be giving your lower abs as much love as you'd like. That's why leg raises (aka leg lifts) deserve to be your new go-to core move.

• ​What is a leg raise?​ It's an ab exercise that involves lying flat on the floor and using your abs to lift your legs up toward the ceiling. Your back stays rooted into the floor at all times.
• ​What muscles do leg raises work?​ It mainly strengthens your core, specifically your abdominals, according to Melissa Garcia, DPT, a Washington-based physical therapist. It really zones in on the lower part of both your rectus abdominis (RA), your six-pack muscle, and your transverse abdominis (TA), which stabilizes your spine. But it also strengthens your hip flexors, which connect your torso to your lower body.
• ​Are leg raises good for your abs?​ They're great for sculpting your deep core muscles, including the lower fibers of your abs.
• ​Who can do leg raises?​ It is safe for anyone that can comfortably get down on and up off the floor. But it does require some mobility in the hips, so it's OK if you can't raise your legs all of the way from the floor to the ceiling. Anyone dealing with lower back pain should try a modified version before they move through a full range of motion, Garcia says. As long as you can do the move pain-free, it's OK to progress.

Want to try it out? Here's everything you need to know about the must-try ab move.

Sure, leg lifts strengthen your rectus abdominis, or six-pack muscle, but they also target the deep stabilizing muscles in your trunk, according to New York-based personal trainer Carolina Araujo, CPT.

This includes your transverse abdominis. Although TA isn't as visible as the surface RA muscle, it's a big help in your day-to-day movements, supporting your spine, improving your total-body strength and acting like an internal corset.

Although they're primarily an ab exercise, LRs strengthen your hips, too, Araujo says. During the exercise, your hip flexors work with your abdominals to raise and lower the weight of your legs.

What are your hip flexors: Located across the front of your hip pelvis, these muscles help keep your lower body stable. But because most people spend their day seated at a desk, they're often tight (aka weak), leaving the hips and knees vulnerable to injury, she says.

Strengthening your hip flexors can help keep your hips and legs working their best, and without injury.

By strengthening your core and hips, leg lifts stabilize your spine and pelvis, according to Araujo. This can help reduce some of the rounded-spine, hunched-over posture that is so common and contributes to back pain.

Improving your posture can also help you move easier (and more efficiently) during sports like running, lifting, climbing and cycling.

The key to a good LR is keeping your entire back — that includes the small of your back — flat against the floor, Garcia says. When you let your back arch, you dump stress your lower back. Apart from hurting your back, this leg raise mistake also negates all of the core strengthening you're trying to do.

Focus on actively pressing your back into the floor and only lowering your legs as far as you can without your back raising.

To really target the small stabilizing muscles in your core, you want to lift and lower your legs as deliberately as possible, according to Araujo. Otherwise, you let momentum do all of the hard work for you.

Pro tip: Lower your leg for a three-second count to guarantee you're not moving too fast. "Don't let your legs flop to the ground on the way down," she says. "If you're having trouble controlling the movement, bend your knees or keep a lower range of motion."

To make this ab strengthener more difficult or mix up the muscles you work, try these leg lift variations and progressions.

Instead of lifting both legs to the ceiling, raise one leg while the other rests on the ground. For more of a challenge, Araujo recommends hovering your working leg a few inches off the floor.

The slower you lower the legs, the harder the exercise becomes, Garcia says. Try to lower your legs for a 4-second count while keeping your back glued to the floor.

Adding a crunch to your leg lifts lets you also hit your upper abdominals, too, Araujo says. As you lift your legs up to the ceiling, crunch your shoulder blades up off the floor a few inches.

Toss on a pair of ankle weights to increase how hard your ab and hip muscles have to work, Garcia says. But only add extra resistance if you can do the exercise with good form, back flat.

Bracing a stability ball between your ankles forces you to work your inner thighs and really move with control. If you don't have a stability ball handy, try it with a pillow.