Stop Doing the Single Leg Lift Like This (Save Your Back)
You might think lying on the floor and lifting one leg is the easiest thing you can do in the gym. But if you are feeling a pinch in your lower back instead of a burn in your deep abdominals, you are wasting your time.
The single leg lift is one of the most deceptive exercises in fitness. It looks like a beginner move, but it requires significant pelvic control to execute correctly. When done right, it acts as a diagnostic tool for hip imbalances and a builder of bulletproof core stability. When done wrong, it’s a recipe for lumbar strain.
Key Takeaways: Mastering the Single Leg Raise
- Primary Focus: Targets the lower rectus abdominis and iliopsoas (hip flexors).
- Crucial Cue: Maintain a "posterior pelvic tilt" (press your lower back into the floor) throughout the entire range of motion.
- Regression: If your back arches, bend the knee of the non-working leg to stabilize the pelvis.
- Benefit: Corrects left-to-right strength imbalances that double leg lifts often mask.
Why the One Leg Lift Exercise is Superior to the Double
We often rush straight to double leg raises because they look cooler and feel harder. However, the one leg lift exercise offers unique benefits that bilateral (two-legged) movements cannot match.
When you lift both legs, your stronger side often compensates for the weaker one. By isolating one side, you force the stabilizing muscles—specifically the obliques and the deep transverse abdominis—to work overtime to prevent your torso from rotating. This unilateral focus helps fix the strength gaps that lead to injuries during heavy compound lifts like squats or deadlifts.
How to Execute Lying Single Leg Raises Perfectly
Forget about how high you can lift your leg. The goal here is tension, not range of motion. Here is how to set up the single leg raise exercise for maximum recruitment.
1. The Setup
Lie flat on your back. This is where most people fail immediately. Reach under your lower back with your hand. Is there a gap? If so, you are in an anterior pelvic tilt. Exhale sharply and drive your ribcage down, crushing your lower back into the floor. There should be zero space between your spine and the mat.
2. The Movement
Keep one leg planted. You can keep it straight (harder) or bent with the foot flat on the floor (easier/safer). Slowly lift the working leg toward the ceiling. Keep the knee straight but not hyperextended.
3. The Descent
This is the money maker. Lower the leg slowly. Stop before your heel touches the ground. More importantly, stop the moment you feel your lower back start to peel off the floor. That is your active range of motion. Going lower than that disengages the abs and shifts the load entirely to the spine.
Common Mistakes with Single Leg Raises
The "Hip Snap"
If you hear or feel a clicking sound in your hip during single leg raises, you likely have tight hip flexors or you are losing core tension. This is often called "snapping hip syndrome." To fix this, reduce your range of motion. Don't lower the leg as far, and focus on stretching your hip flexors before the workout.
Momentum Over Muscle
Swinging the leg up uses momentum, not muscle. The one leg raise exercise should be performed at a tempo. Try a count of two seconds up, two seconds down. If you can't control the speed, you aren't controlling the weight of your leg.
My Training Log: Real Talk
I remember distinctly when I realized I was doing these wrong. I was recovering from a minor lower back tweak and decided to regress my training to basics. I lay down on the gym floor—specifically that rubber tiling that leaves a grid pattern on your skin—and tried to do a set of 20.
By rep 12, my hip flexor was screaming, but my abs felt fine. That was the problem. I wasn't using my core; I was just levering my leg up and down with my hip muscles. I also noticed a very specific wobble. When I lowered my right leg, my left hip would subtly pop up off the floor, shifting my weight. I wasn't stable at all.
I had to swallow my pride and bend my non-working knee, planting that foot firmly on the floor. It felt like a "beginner" modification, but suddenly, the tremor in my lower abs was violent. That shaking was proof I was finally hitting the target. If you don't feel that deep, uncomfortable shake, you're probably letting your back do the work.
Conclusion
The one leg lift isn't just a warm-up; it's a fundamental pattern for core health. Stop chasing rep counts and start chasing pelvic stability. Once you can perform these with zero back arching, you have earned the right to move on to double leg variations.
Frequently Asked Questions
Is the single leg lift exercise safe for bad backs?
Generally, yes, it is safer than double leg lifts. However, you must keep the non-working leg bent with the foot flat on the floor. This unlocks the pelvis and allows you to keep your lower back flat, reducing shear force on the lumbar spine.
Do lying single leg raises burn belly fat?
No exercise spot-reduces fat. Lying single leg raises will strengthen and hypertrophy the abdominal muscles, but revealing those muscles requires a caloric deficit to reduce overall body fat percentage.
Why do my hips pop during single leg raises?
This clicking is usually a tendon snapping over a bony prominence in the pelvis, often due to tight hip flexors (iliopsoas). Stretching your hips beforehand and limiting the range of motion so the leg doesn't go all the way down usually resolves this.
