3/4 Sit-Up
The 3/4 sit-up curls your torso most of the way toward your knees, stopping just short of a full sit-up, using your abdominals through a longer range than a crunch while asking less of your hip flexors than the last stretch of a complete sit-up. It's a middle-ground option: more demanding than a crunch, gentler than a full sit-up, and a sensible place to build toward the complete range.
Why it works
As your torso rises off the floor during a sit-up, the abdominals do most of the early work, but the final quarter, where your torso approaches vertical, increasingly relies on the hip flexors to finish the job. Stopping at three quarters keeps the movement in the range where your abs are doing the heaviest lifting, which is often exactly what someone wants if they're building ab strength without wanting the hip flexors to dominate the exercise. It's a practical middle step for anyone whose full sit-up feels more like a hip flexor exercise than an ab one.
Set up
- Lie on your back with your knees bent and feet flat on the floor, hip-width apart.
- Cross your arms over your chest or lightly support your head with your fingertips, without pulling on your neck.
- Brace your core lightly before the first rep.
How to do it
- Curl your chest up and forward toward your knees, leading with your upper abs.
- Continue rising until your torso is roughly three quarters of the way toward vertical.
- Pause briefly at that point, feeling the tension across your abdominals.
- Lower your torso back down with control, keeping the movement smooth.
- Stop just before your shoulder blades touch the floor and begin the next rep.
- Keep your feet planted throughout; don't let them lift as you curl up.
Form cues
- Curl, don't yank the neck.
- Stop at three quarters, not full sit-up height.
- Feet planted the whole rep.
- Smooth up, smooth down.
Breathing: Exhale as you curl up, inhale as you lower back down.
Common mistakes
Yanking the head and neck forward to help the torso rise.
Fix: Keep your fingertips light against your head, and let your abs lead the movement rather than your neck muscles.
Letting the feet lift off the floor as the torso curls up.
Fix: Press your heels down actively throughout the rep; lifting feet is often a sign the abs are fatiguing and other muscles are compensating.
Using momentum to swing up instead of a controlled curl.
Fix: Slow the tempo down; a controlled 3/4 curl trains more than a fast, momentum-driven one.
Rushing back down and letting the torso drop rather than lowering with control.
Fix: Control the descent just as deliberately as the rise; the lowering phase is doing real work too.
How to program it
- Start with 2 or 3 sets of 10 to 15 reps, two or three days a week.
- Use it as a stepping stone toward the full sit-up, or keep it as your regular ab movement if you prefer less hip flexor involvement.
- Progress by adding a brief pause at the top of the range before moving to the full sit-up or a resisted version.
- Pairs well with a lower-ab move like the reverse crunch to train the abdominal wall from both ends.
Safety notes
- If your neck strains, support your head lightly with your fingertips rather than pulling it forward with your hands.
- If your lower back arches at any point, shorten the range slightly until your core control catches up.
Exercise profile
- Force
- Pull
- Mechanics
- Compound
- Category
- Strength
Frequently asked questions
What's the difference between a 3/4 sit-up and a full sit-up?
A full sit-up brings your torso all the way to vertical, relying more on the hip flexors in that final stretch. The 3/4 version stops short of that point, keeping more of the work on the abdominals throughout the range.
How many 3/4 sit-ups should I do?
Ten to fifteen controlled reps, for 2 or 3 sets, is a reasonable starting point. Prioritize a smooth, controlled curl over a high rep count.
Why does my neck hurt during sit-ups?
Usually the hands are pulling the head forward to help the torso rise. Rest your fingertips lightly against your head instead, and let your abdominals do the lifting.
Is a 3/4 sit-up better than a full sit-up for beginners?
For many beginners, yes: it trains the abs through a solid range while asking less of the hip flexors than the final stretch of a full sit-up, which some people find less controlled early on.