Flat Bench Leg Pull-In
The flat bench leg pull-in has you sitting at the end of a bench, hands gripping behind you for support, knees drawing in toward your chest and then extending back out. It's a compound core move that trains the lower abdominals through a full range of hip flexion, using your own body weight as the only resistance. It suits beginners building core control as well as anyone who wants an equipment-free ab exercise with a longer range of motion than a standard crunch.
Why it works
Bringing your knees toward your chest is hip flexion, and your abdominals, especially the lower fibers of the rectus abdominis, work alongside your hip flexors to pull your legs in and keep your pelvis from tipping forward as they move. Sitting on the edge of the bench with your hands behind you for support removes your legs from the floor entirely, so there's no assistance from pushing off the ground, which means your core has to control the entire arc from extended to tucked and back again.
Set up
- Sit near the end of a flat bench, hands gripping the edge behind your hips for support.
- Lean back slightly and lift your feet off the floor, legs extended out in front of you.
- Brace your core before your first rep.
- Keep your chest up rather than collapsing forward.
How to do it
- Draw your knees in toward your chest, curling your hips and lower back slightly as they come in.
- Pause briefly with your knees pulled in close.
- Extend your legs back out to the starting position under control.
- Keep your feet off the floor for the entire set.
- Repeat without letting your lower back arch as your legs extend.
Form cues
- Curl the hips in, don't just bend the knees.
- Keep your feet off the floor the whole set.
- Chest stays up, not collapsing forward.
- Control the extension; don't let your legs drop.
Breathing: Exhale as you draw your knees in, inhale as you extend your legs back out.
Common mistakes
Letting the feet touch the floor between reps.
Fix: Keep your feet hovering off the ground for the entire set; touching down gives your abs a rest the exercise isn't meant to offer.
Arching the lower back as the legs extend out.
Fix: Keep a slight posterior pelvic tilt throughout and stop extending your legs at the point where your lower back would start to arch.
Using momentum to swing the legs in and out quickly.
Fix: Slow the tempo down; a controlled pull-in trains the abs far more than a fast swing that relies on momentum.
Leaning too far back and collapsing the chest.
Fix: Keep your chest lifted and your arms only slightly behind your hips rather than reclining flat.
How to program it
- 2 to 3 sets of 10 to 15 reps works well as core-focused work, and two or three times a week is a reasonable frequency for a bodyweight ab exercise like this.
- Place it alongside other core work like planks rather than as a standalone session; the abs recover quickly enough to train fairly often.
- Progress by slowing the tempo or adding a brief pause at the tucked position before adding an unstable surface.
- If your hip flexors fatigue faster than your abs, that's normal at first, since both muscle groups share the pulling-in motion.
Safety notes
- Stop the leg extension before your lower back starts to arch off its neutral position.
- If you feel strain in the lower back rather than effort in the abs, shorten the range of motion or try the floor-based regression.
Exercise profile
- Force
- Pull
- Mechanics
- Compound
- Category
- Strength
Frequently asked questions
How many reps of leg pull-ins should I do?
10 to 15 controlled reps for 2 or 3 sets is a solid target. Slow, controlled reps build more core strength here than fast, momentum-driven ones.
Why does my lower back arch during leg pull-ins?
Extending the legs too far, or too fast, can pull the pelvis forward if the core isn't controlling the movement. Shorten the range and slow down until you can keep the lower back from arching.
Can I do leg pull-ins without a bench?
Yes, doing the same knee tuck seated or lying on the floor works the same pattern with a slightly shorter range of motion.
What's harder than the flat bench leg pull-in?
The exercise ball pull-in, which uses an unstable ball under your feet, adds a balance challenge on top of the same core movement.