Sit-Up
The sit-up takes the crunch through a longer range, adding hip flexion once the spine has finished rounding. That extra range brings the rectus femoris and other hip flexors into play, so it trains the abs and the front of the hip together. It is a durable, equipment-free builder for general core strength and athletic conditioning.
- Equipment
- Body Weight
- Body part
- Abs
- Type
- Strength
- Browse by muscle
- Upper Rectus Abdominals
- Browse by movement
- Spinal Flexion
- Target
- Upper Rectus Abdominals
- Secondary
- Rectus Femoris
- Tertiary
- Abdominal External Oblique
How to do it
- 1
Lie on your back with knees bent and feet anchored or flat on the floor.
- 2
Cross your arms on your chest or reach your hands toward your thighs.
- 3
Exhale and curl your torso up, rounding the spine first, then folding at the hips.
- 4
Sit tall with your chest near your thighs.
- 5
Inhale and lower vertebra by vertebra back to the floor.
- 6
Keep the movement smooth rather than snapping up with momentum.
Tips
- Peel your spine off the floor one segment at a time instead of hinging as a rigid plank.
- If your feet lift, hook them under something or have a partner hold them.
- Avoid pulling on your neck; let your abs initiate every rep.
Variations
Common mistakes
- Arms swing forward to launch the rep, and once the hands lead, the abs are along for the ride; crossing them on the chest makes the movement honest again.
- The heels drag backward toward the hips at the top of each rep, a clear sign the hip flexors have taken over the second half of the movement.
- Feet get anchored under something heavy from the first session, which lets the hips rescue reps a weak trunk cannot produce; anchor them because your legs are long, not to save a set.
- The descent is dropped rather than lowered, so half of every rep is given away to gravity; take about two seconds to lay the spine back down.
- Reps get counted in the hundreds because the movement is easy, when a slower set of fifteen does more for the abs than a fast set of fifty.
Frequently asked
- How many sit-ups should a beginner do?
- Three sets of 10 to 15 reps at a controlled pace, three times a week, is a solid start. Build to 20 clean reps per set, then stop adding reps and add time under tension instead: three seconds down, or a pause with the shoulder blades an inch off the floor. If ten reps are out of reach, spend a few weeks on crunches and on reaching the hands along the thighs, which shortens the lever and lets the curl develop first.
- How do you make the sit-up easier or harder?
- Easier: reach the hands toward the thighs, bring the feet closer to the hips, or stop halfway and treat it as a crunch until the range feels controlled. Harder: cross the arms on the chest, then hold the fingertips at the temples, then reach both arms overhead, which is the largest jump of the three. Slowing the descent to three seconds, unanchoring the feet, or lying on a slight decline all add difficulty without any weight.
- Are sit-ups still worth doing?
- For most people, yes, with one condition. They build trunk flexion strength through a longer range than a crunch and bring the hip flexors in, which transfers to getting up off the floor, to wrestling and combat sport, and to any fitness test that still scores them. They cost nothing and need no equipment. The condition is your back: if it is sensitive to repeated bending, planks, dead bugs, and carries train the same trunk with the spine still. Flexion is also only one of the jobs a core does, so pair them with rotation and anti-extension work.
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