To get those abs to pop you have to lose enough abdominal fat to uncover the ab muscles, but you also have to hypertrophy the abs. There’s no shortage of exercises that work the muscles that make up your abs. The most popular is the abdominal crunch. However, abdominal crunches involve flexion of the spine and some physical therapists believe that this exercise isn’t safe for people with lower back pain. Another popular exercise for the abs is leg raises.
You’re probably familiar with leg raises. Here’s how to do this exercise:
- Lie on a mat with your arms by your side and your legs together.
- Keeping your torso and head on the floor, slowly raise your legs off the floor with your toes pointed.
- Keep raising your legs until they’re perpendicular to the ceiling.
- Slowly lower your legs back down to the floor until they’re just above the ground.
- Repeat in a controlled manner.
Now you know how to do a leg raise, but how effective is this exercise for hypertrophying your abdominal muscles and getting that elusive six-pack?
It might surprise you to learn that leg raises are not an exercise that specially targets the two rectus abdominis muscles that run vertically down your torso and give your abs definition. In fact, the muscles that contract when you do a leg raise are your hip flexors, mainly the psoas muscles.
The psoas muscles on either side of your torso connect the lower portion of your spine to your upper leg or femur. Their function is to flex your hips and lift your legs toward your body. Each time you do a leg raise you call upon these muscles to contract. Therefore, they’re doing most of the work when you perform leg raises, not your rectus abdominis muscles. It’s only when you raise your legs higher than 90 degrees above the floor that your rectus abdominis muscles contract.
Yet your rectus abdominis muscles get some stimulation when you do this exercise even if you don’t raise your legs beyond 90 degrees. That’s because when your abdominal muscles contract they stabilize your body when you raise your legs. Therefore, they contract isometrically for stabilization but play a secondary role to your hip flexors. If you’re trying to hypertrophy your abdominal muscles, leg raises shouldn’t be the main exercise you do.
How Safe Are Leg Raises?
Another concern is whether leg raises are safe for your back? Leg raises can contribute to lower back pain in people with tight hip flexors. That’s because this exercise strengthens hip flexors that are already too tight and this creates an imbalance between the hip flexors and hip extensors, the muscles in the back of the hip that lift your leg away from your body. An imbalance between the two muscle groups increases the risk of pain in the hips and lower back and boosts the risk of sports injuries. Ideally, you want the flexors and extensors to be in balance so that one side isn’t pulling too hard on the other.
The problem is most people have hip flexors that are already too tight. Rather than strengthening their hip flexors more, these folks should stretch their hip flexors and strengthen the opposing muscles, the hip extensors. There are a variety of stretches you can do, such as butterfly stretches to counter tight hip flexors. If you sit a lot, these should be part of your fitness routine.
Where does this epidemic of hip flexor tightness come from? The main culprit is too much sitting. When you sit in a chair for long periods of time, your hip flexors shorten. Over time, they become weaker and less flexible. People who run or cycle for long distances are also prone to tight hip flexors. The opposing muscles, including the glutes, are weaker by comparison.
Mistakes People Make with Leg Raises
Now that you know that leg raises target your hip flexors more than your abs and your abs only act as stabilizers, you might limit the number you do. If you do them, avoid making these common mistakes.
The most common mistake people make when they do leg lifts is they arch their lower back. Your back shouldn’t be flat against the mat as your lumbar area has a natural curve, but you shouldn’t raise your back as you raise your legs. Another mistake is doing the movement too quickly. Do each repetition in a slow and controlled manner. Your abs should be tight and under tension throughout the movement. Remember, you’re trying to get your abs involved as much as possible.
Better Abdominal Exercises
As you can see, leg raises to 90 degrees target your hip flexors more than your abs. Therefore, they shouldn’t make up the bulk of your abdominal routine and if you have lower back pain, avoid them entirely. A better alternative is to do exercises that work your entire core like planks and their many variations. Planks work all of the muscles in your core. However, you still need to target the rectus abdominis muscles since hypertrophy of these muscles is what gives abdominal definition. A 2001 study by the American Council on Exercise used EMG data to look at which exercises were effective and which were less so. Exercises near the bottom of the list were less effective. Some of these exercises, like torso tracks and ab rockers used abdominal exercise gadgets popular at the time.
- Bicycles
- Captain’s chair
- Crunches on an exercise ball
- Vertical leg crunch
- Torso track
- Crunches with arms extended above head
- Reverse crunch
- Crunch with heel push
- Ab Roller
- Hover
- Standard crunch
- Exercise tubing pull
- Ab rocker
As you can see, certain exercises like ab rockers, tubing pulls, standard crunches, and hovers underperformed relative to movements like bicycles and captain’s chair. Plus, participants reported back pain when using the torso track. In fact, you should be frugal about which exercise you do if you have lower back pain. Planks are safer than exercises where you flex your spine like crunches. Also, you won’t get abs if you don’t mind your diet! You need to trim the fat that covers the abs.
References:
American Council on Exercise. “American Council on Exercise (ACE)-sponsored Study Reveals Best and Worst Abdominal Exercises”
Related Articles by Cathe:
Are Planks Better Than Crunches for Abdominal Development?
Signs You Have Weak Core Muscles and How to Power Up Your Core
Abdominal Exercises: Are You Doing Too Many Reps?
Ab Training: Can the Quest to Get Defined Abdominals Lead to Back Pain?
Flabby Abs? It Could Be Bad Posture. Find Out What to Do About It
