Leg Pull-In
The leg pull-in is a floor-based core exercise where you lie back, brace your torso, and pull your bent knees toward your chest using your abs instead of your hip flexors. It's a beginner-friendly way to target the lower abdominals without any equipment, and the compound bending of the hips and spine makes it a natural stepping stone toward harder bench-based or hanging knee raises.
Why it works
Bringing the knees toward the chest can come from two very different places: the hip flexors pulling the thighs up, or the abdominals curling the pelvis and lower spine. The leg pull-in asks for the second one. By keeping your upper back pinned to the floor and focusing the movement on tilting your pelvis rather than swinging your legs, you shift the load onto the rectus abdominis and obliques instead of letting the hip flexors do all the work, which is the difference between a real ab exercise and a hip flexor drill in disguise.
Set up
- Lie face up with legs straight out in front of you, hands flat on the floor at your sides or tucked lightly beneath your hips for support.
- Press your lower back gently into the floor before you start moving.
- Bend your knees slightly to bring your feet a few inches off the ground.
How to do it
- Pull your knees toward your chest by curling your pelvis and lower spine, not by yanking with your hip flexors.
- Bring your knees as close to your chest as you can while keeping your upper back flat on the floor.
- Pause briefly at the top, feeling the contraction through your lower abs.
- Extend your legs back out slowly until they're almost straight, without letting your lower back arch off the floor.
- Repeat for the set, keeping the tempo slow enough that momentum isn't doing the work.
Form cues
- Curl the pelvis, don't just swing the knees
- Upper back stays flat throughout
- Slow the extension, don't let the legs drop
- Exhale on the pull, not before it
Breathing: Exhale as you pull your knees toward your chest, inhale as you extend your legs back out.
Common mistakes
Letting the lower back arch off the floor as the legs extend.
Fix: Stop the extension a little short of straight legs until your core is strong enough to keep the back flat through the full range.
Using the hip flexors to yank the knees up quickly.
Fix: Slow down and focus on curling the pelvis first, letting the knees follow.
Holding the breath through the set.
Fix: Exhale as you pull the knees in; holding your breath adds unnecessary tension and can spike your blood pressure.
How to program it
- As a bodyweight core move, this can be trained often, most people do fine fitting it into three or four sessions in a week.
- Two to three sets of 12 to 15 reps is a solid starting point; add reps before adding difficulty.
- It works well paired with a bridge or plank in the same core circuit, since together they train flexion and stability from different angles.
Safety notes
- If your lower back lifts off the floor at any point, shorten the range of motion until your core can control it.
- Skip high rep counts if you feel this in your hip flexors or lower back more than your abs; quality reps matter more than volume here.
Exercise profile
- Force
- Pull
- Mechanics
- Compound
- Category
- Strength
Frequently asked questions
How many reps of leg pull-ins should I do?
Two to three sets of 12 to 15 reps is enough for most people starting out; the exercise works best with clean, controlled reps rather than pushing for a high number.
Leg pull-in vs regular leg raise: what's the difference?
The leg pull-in bends the knees and pulls them toward the chest, which is easier on the lower back. The straight-leg raise works the same lower abs but with a longer lever, making it noticeably harder.
Why do I feel this in my hip flexors instead of my abs?
You're likely swinging the legs up quickly instead of curling the pelvis. Slow the movement down and think about tilting your hips toward your ribs rather than lifting your knees.
Can I make the leg pull-in harder without extra equipment?
Yes, doing it on a bench with your hips near the edge lets your legs travel through a longer range, since they can extend below the level of your hips before you pull them in.
How many reps until I'm ready for a straight-leg raise?
Once three sets of 15 clean reps of the leg pull-in feel easy with no lower-back arching, the straight-leg raise is a reasonable next step, since it lengthens the same lever and increases the demand.