Why Do I Feel Leg Lifts in My Hip Flexors

Your Abs Aren't Weak, Your Hip Flexors Are Just Bullies

The reason why you feel leg lifts in your hip flexors is because your hip flexors are anatomically designed to lift your legs-it's their primary job, and they're doing about 90% of the work until you consciously force your abs to take over. You lie down on the mat, determined to carve out your lower abs. You start your set of leg lifts, and five reps in, the only thing on fire is that deep, grabbing sensation at the top of your thighs. It’s frustrating. You’re trying to build a stronger core, but an entirely different muscle group seems to be screaming for a break. This isn't a sign that you're weak or doing it completely wrong. It's a sign that a stronger, more dominant muscle group is hijacking the movement. Your hip flexors, specifically the psoas and iliacus muscles, are bullies. They are incredibly efficient at their job: flexing the hip. When you perform a leg lift, they jump in immediately to do the heavy lifting, leaving your abdominal muscles with very little to do. The goal isn't to stop the hip flexors from working-that's impossible. The goal is to shift the workload so your abs become the primary stabilizer and tension-holder, turning the exercise from a hip flexor lift into a true abdominal challenge.

The Hidden Muscle Doing All the Work (And How to Fire It)

To understand why your hips take over, you need to look at the mechanics. Your hip flexor muscles connect your thigh bone (femur) to your pelvis and lower spine. Their job is to pull your knee towards your chest. Your main abdominal muscle, the rectus abdominis, runs from your ribcage down to the front of your pelvis. Its job is to either curl your upper body towards your knees (a crunch) or tilt your pelvis backward. During a standard leg lift, most people focus only on lifting and lowering their legs. When you do this, your lower back naturally arches slightly off the floor. This arch is the critical mistake. The moment your back arches, your pelvis tilts forward, which disengages your abdominal wall and gives your hip flexors perfect leverage to take over the entire movement. You are effectively turning off the very muscles you want to train. The secret to fixing this is to reverse that movement with a posterior pelvic tilt. This is the “on” switch for your lower abs. By actively pressing your lower back into the floor and tilting your pelvis backward, you shorten the distance between your ribs and your pelvis. This pre-tenses the abdominal wall and forces it to remain the primary stabilizer throughout the entire exercise. Your hip flexors still help lift the legs, but now your abs have to fight like crazy to maintain that pelvic tilt, which is where the real work happens.

Tired of guessing? Track it.

Mofilo tracks food, workouts, and your purpose. Download today.

The 3-Step Fix: A 5-Minute Drill to Re-Wire Your Leg Lifts

Feeling your abs during a leg lift isn't about strength; it's about motor control. You have to teach your brain to fire your abs first and keep them engaged. This 3-step progression will re-wire that connection. Do this drill 3-4 times a week. For the first two weeks, this IS your ab workout. Don't rush to the full, straight-leg version. Master each step before moving on.

Step 1: Master the Pelvic Tilt (The "On" Switch)

This is the foundation. Do not skip it. Lie on your back with your knees bent and feet flat on the floor, about hip-width apart. Place one hand in the small space under your lower back. Your goal is to flatten your back and "crush" your hand against the floor. To do this, gently rock your hips so your tailbone lifts slightly and your pubic bone tilts up toward your belly button. You should feel your lower abs tighten immediately. Hold this contraction for 5 seconds, focusing on breathing without losing the tension. Then, relax. That's one rep. Perform 2 sets of 10 reps. The movement is small, almost invisible, but it's the most important part of the entire process.

Step 2: The Heel Slide Progression

Once you can hold the pelvic tilt without thinking, it's time to add leg movement. Lie on your back and establish your strong pelvic tilt, pressing your lower back firmly into the floor. Now, slowly slide the heel of your right foot away from you until your leg is almost straight. Go only as far as you can *without* your lower back arching off the floor. The instant you feel that space appear under your back, you've gone too far. Your abs have failed. Pause, then use your abs to pull the heel back to the starting position. Perform 8-10 reps on the right side, then switch and do 8-10 reps on the left side. Complete 2 sets. This teaches your abs to stay engaged while your hip flexors are moving your leg.

Step 3: The Bent-Knee Leg Lower

This is your new leg lift. Lie on your back and engage the pelvic tilt. Lift your feet off the floor and bring your knees up to a 90-degree "tabletop" position (shins parallel to the floor). This is your starting position. Re-check your lower back-it must be flat. Slowly, and with control, lower both heels toward the floor. Only go as low as you can maintain the flat-back position. For most people, this will be a drop of only 6-12 inches at first. Then, use your lower abs to pull your knees back up to the tabletop start. If this is too hard, start by lowering one leg at a time. Your goal is to complete 3 sets of 12-15 reps with perfect form. Once you can do this easily, you are ready to start working toward a straight-leg version, but only by lowering your legs to a 45-degree angle, not all the way to the floor.

What to Expect: Your First 2 Weeks Will Feel Weaker

Here’s the honest truth: when you start doing leg lifts correctly, you will feel significantly weaker. You might go from doing 25 sloppy, hip-flexor-dominant reps to struggling to get 8 perfect, ab-focused reps. This is not a step backward. This is a massive leap forward. It means you are finally training the muscle you intended to train.

Week 1: Your entire focus is on the pelvic tilt and heel slides. You might not even attempt a bent-knee leg lower. Your lower abs will likely feel sore in a way they never have before. This is the feeling of waking up dormant muscle fibers. You will feel the connection between your brain and your abs getting stronger with every rep.

Weeks 2-4: You will be working with bent-knee leg lowers. You will notice your abs start to shake around rep 8 or 10. This is a great sign. It's called neuromuscular fatigue, and it means you're challenging the muscle effectively. Your endurance will slowly increase from 8 reps to 10, then 12, then 15. Don't add ankle weights or rush to straight legs. Own this phase.

Month 2 and Beyond: You can now begin experimenting with straight-leg lifts, but with a modification. Instead of lowering your legs all the way to the floor, only lower them about 45 degrees. This maintains tension on the abs without letting the lower back arch and the hip flexors take over. The range of motion is smaller, but the quality of the contraction is 100 times better. True core strength isn't about how far your legs can move; it's about how well your abs can prevent unwanted movement in your spine.

You read this far. You're serious.

Track food, workouts, and your purpose with Mofilo. Download today.

Frequently Asked Questions

The Role of "Tight" Hip Flexors

Stretching your hip flexors feels good, but it won't solve this problem. The issue is one of motor control and relative strength, not just flexibility. Your brain is simply choosing the path of least resistance (your hips). The fix is to strengthen the opposing muscles-your glutes and abs-to teach your pelvis how to stay in a neutral or slightly tilted-back position during movement. Strengthening is more effective than stretching here.

Feeling Leg Lifts in Your Lower Back

If you feel any strain or pain in your lower back, stop immediately. This is a major red flag that your abs have completely disengaged and your spine is hyperextending to compensate. Your body is using your spinal erectors to lift, which is inefficient and dangerous. Regress to the pelvic tilt and heel slide exercises until your core is strong enough to prevent this.

Hanging Leg Raises vs. Lying Leg Lifts

Hanging leg raises are an advanced progression, not a starting point. They are significantly harder because your abs have to stabilize your entire torso against the full weight of your legs fighting gravity. All the same rules apply: you must initiate the movement with a slight pelvic tilt to engage the abs. If you can't do a perfect lying leg lift, you are not ready for the hanging version.

Better Exercises for Lower Abs

If leg lifts continue to give you trouble, focus on exercises that force the same pelvic control with less hip flexor involvement. Reverse crunches are excellent for this, as you are using your abs to pull your knees toward your chest. Dead bugs are another top-tier choice, as they directly train your abs to stabilize the spine while your limbs are moving-the exact skill needed for a perfect leg lift.