Do Leg Raises Work Abs? The Truth About Lower Core Training
Walk into any gym, and you will see someone lying on a mat, furiously flailing their legs up and down. They are chasing the elusive "lower ab" pop. But if you ask them where they feel the burn, they might point to their hips or, worse, their lower back. This leads to the critical question: does leg raises work abs effectively, or are they just a recipe for hip pain?
The answer isn't a simple yes or no. It depends entirely on biomechanics and intent. If you execute them poorly, you are building hip flexors. If you execute them with precision, they are one of the best core developers in your arsenal. Let's break down the science and fix your form.
Key Takeaways
- Yes, they work abs: Leg raises primarily target the lower region of the rectus abdominis, but only if the pelvis curls.
- Hip flexors are dominant: The iliopsoas muscles are the primary movers for lifting the legs; the abs act as stabilizers until the hips curl off the floor or bench.
- Posterior Pelvic Tilt is mandatory: To engage the abs, you must flatten your lower back against the floor (or curl the pelvis up if hanging).
- Control over reps: Swinging momentum kills the tension on the abs and transfers it to the lower back.
The Anatomy of the Leg Raise
To understand if leg raises are effective, you have to look at what moves what. Your legs are heavy. The muscles responsible for lifting your thigh toward your torso are the hip flexors (specifically the iliopsoas and rectus femoris).
Your abdominal muscles do not attach to your legs. They attach to your pelvis. This is a crucial distinction.
What Part of Abs Do Leg Raises Work?
Technically, the rectus abdominis is one long muscle sheet. However, different exercises stimulate different regions based on leverage. Do leg lifts work abs throughout the entire length? Yes, isometrically.
But, they target the "lower abs" through a reversed crunch motion. The abs work dynamically only when the pelvis rotates toward the ribcage. If you just lift your legs without moving your hips, your abs are merely bracing to keep your spine safe while your hip flexors do all the heavy lifting.
Are Leg Raises Effective? (The Form Factor)
Leg raises are highly effective, but they have a steep learning curve. The movement pattern is deceptive. Most people think the goal is to get the feet high. It isn't. The goal is to curl the pelvis.
The "Lying" Variation
When performing these on the floor, the most common mistake is arching the lower back as the legs lower. This is the "danger zone." If your lower back peels off the floor, your abs have disengaged, and the heavy load of your legs is now pulling directly on your lumbar spine.
To ensure do leg raises work abs and not your spine, you must maintain a "hollow body" position. Press your lower back aggressively into the floor. If you feel it lift, you have lowered your legs too far.
Common Mistakes and How to Fix Them
You might be wondering, "do leg raises work abs if I bend my knees?" Actually, yes, and often better.
1. The Straight Leg Ego Trap
Keeping legs perfectly straight increases the lever arm, making the exercise significantly harder. If your core isn't strong enough, your hip flexors take over. Bending the knees shortens the lever, allowing you to focus on the pelvic curl rather than struggling to lift the weight of your legs.
2. Using Momentum
If you are swinging your legs up, you are using physics, not muscle. Momentum bypasses the stickicking point where the muscle fiber recruitment is highest. Slow down. Take three seconds to lower your legs. That eccentric control is where the strength is built.
My Training Log: Real Talk
I remember the first month I added hanging leg raises to my routine, thinking I was going to carve out a six-pack in weeks. I was dead wrong. I hopped up on the bar, grabbed the aggressive knurling that felt like a cheese grater against my palms without chalk, and started cranking out reps.
By rep 10, I wasn't feeling a burn in my stomach. I felt a deep, annoying ache in the front of my hips, right in the crease. Worse, I started swinging like a pendulum because my grip was failing before my core did. I’d drop off the bar with my forearms pumped and my lower back feeling tight, but my abs felt surprisingly fresh.
It wasn't until I stopped trying to touch my toes to the bar and focused on "rolling" my hips forward—literally showing the bottom of my glutes to the wall in front of me—that the exercise changed. I had to drop from 15 reps down to 6 strict reps. My ego took a hit, but that was the first time I actually woke up with sore lower abs the next day.
Conclusion
So, do leg raises work abs? Absolutely, but they are a technical lift masquerading as a simple one. If you treat them with the same respect you give a heavy squat—focusing on tension, bracing, and mechanics—they will strengthen your core. If you just flail your legs, you're just asking for a sore back. Master the pelvic tilt, and the results will follow.
Frequently Asked Questions
Do leg raises burn belly fat?
No. Leg raises strengthen the muscle underneath the fat, but they do not spot-reduce adipose tissue. To see the definition, you need to reduce your overall body fat percentage through nutrition and total energy expenditure.
Why does my back click when I do leg raises?
A clicking sound usually comes from the hip tendon snapping over the bone, often caused by tight hip flexors or poor pelvic control. Try reducing the range of motion or bending your knees until you gain more mobility and strength.
Are hanging leg raises better than lying leg raises?
Hanging raises are generally more difficult and require more stabilization, making them "better" for advanced athletes. However, lying leg raises are superior for beginners because the floor provides feedback for your lower back position.
