Seated Leg Tucks
Seated leg tucks work your abdominals by pulling your knees toward your chest while you balance on your seat bones, with no machine or added load involved. It is a floor-friendly way to build core control for people who find a full sit-up or a hanging raise too much too soon. The exercise doubles as a stability drill, since holding the balanced position between reps is half the challenge.
Why it works
Pulling your knees toward your chest shortens your hip flexors and abdominals together, and the seated position adds an extra layer: because you are balanced on your seat bones rather than lying on a mat, your abdominals also work isometrically to keep your torso from tipping backward between reps. That combination, a dynamic knee tuck plus a static torso hold, is what separates this move from a floor-based crunch or reverse crunch.
Set up
- Sit near the front edge of a bench or a sturdy chair.
- Lean your torso back slightly and place your hands on the bench beside your hips for support.
- Lift your feet off the floor and extend your legs out in front of you.
- Brace your core to find your balance point before the first rep.
How to do it
- Pull your knees up and in toward your chest, rounding through your midsection.
- Hold the tucked position for a moment, keeping your balance on your seat bones.
- Extend your legs back out to the starting position without letting your feet touch the floor.
- Keep your torso leaned back at a steady angle throughout the set.
- Repeat for the full set, breathing steadily between reps.
Form cues
- Round through the midsection, not just the hips.
- Keep your feet off the floor the whole set.
- Use your hands for balance, not for lifting.
- Move at a controlled pace, no swinging.
Breathing: Exhale as you tuck your knees toward your chest, inhale as you extend your legs back out.
Common mistakes
Rocking backward and using momentum to swing the knees in.
Fix: Slow the tempo down and pull the knees in with your abdominals rather than swinging your torso.
Letting the lower back round onto the bench between reps.
Fix: Keep a slight lean without collapsing your spine; find a stable angle and hold it.
Gripping the bench so hard that the arms do most of the work.
Fix: Use your hands lightly for balance and let your core drive the knee tuck.
Touching the feet down between reps to rest.
Fix: Keep your feet elevated for the entire set, or use shorter sets if you need a real rest.
How to program it
- As a bodyweight core move, 2 or 3 sets of 10 to 15 reps a few times a week is a reasonable amount to start with.
- It pairs well as a finisher after a lower-body or upper-body session, since it does not add much fatigue to the rest of your training.
- Once holding the tucked position at the top feels easy, add a one or two second pause there before moving on to a hanging variation.
- If balance is the limiting factor rather than ab fatigue, practice the seated hold on its own before chaining full reps together.
Safety notes
- If your lower back rounds excessively or aches, shorten the lean-back angle until your core catches up.
- Keep the movement slow and controlled; a fast, swinging tempo shifts the work from your abs to momentum.
Exercise profile
- Force
- Pull
- Mechanics
- Isolation
- Category
- Strength
Frequently asked questions
How many reps of seated leg tucks should I do?
Start with 2 or 3 sets of 10 to 15 reps. Once that feels easy, add a short pause at the top of each rep instead of rushing to more reps.
Can I do seated leg tucks without a bench?
Yes. Sit on the floor with your knees bent and your hands planted slightly behind your hips for support, then tuck your knees the same way.
What is an easier alternative if I cannot keep my feet off the floor?
A reverse crunch lets you lie down instead of balancing, which removes the stability demand while you build ab strength.
Why does my hip flexor cramp during this exercise?
Your hip flexors assist the knee tuck alongside your abs, so cramping usually means they are fatigued or tight. Slow the tempo and shorten the range slightly if it keeps happening.