Reverse Sit-Up

The reverse sit-up is a bodyweight abdominal exercise performed lying on the floor that trains the lower rectus abdominis by lifting the legs and curling the hips off the ground. Where a regular sit-up lifts the shoulders toward fixed hips, this version fixes the shoulders and moves the pelvis, so the neck stays out of the lift. Unlike thebench reverse crunch, the floor stops the legs at hip level, which keeps the range short and the lower back supported. Lifters program it late in an abs or lower body session as a high-rep accessory.

What Muscles Does the Reverse Sit-Up Work?

• Primary: Rectus abdominis (lower abs)
• Secondary: Iliopsoas and rectus femoris (hip flexors), external obliques
• Tertiary: Transversus abdominis, latissimus dorsi, triceps pressing into the floor

How Do You Set Up for the Reverse Sit-Up?

Lie on your back on a mat with your arms at your sides, palms pressed into the floor beside your hips. Flatten your lower back into the mat and tuck your chin slightly. Lift both feet a few inches off the floor and bend your knees to about 90 degrees so your thighs point straight up and your shins are parallel to the ground. Hold tension in your abs before the first rep.

How Do You Perform the Reverse Sit-Up?

1. Set your knees at 90 degrees with your shins level and your lower back flat against the mat.
2. Curl your hips off the floor by pulling your knees toward your chest, letting your tailbone lift off the mat.
3. Stop when your knees hang over your chest and the lower abs feel fully shortened.
4. Pause for one second at the top with your palms still pressing into the floor and your shoulders relaxed.
5. Lower your hips slowly by uncurling the pelvis onto the mat, then let your knees travel back until your thighs point straight up.
6. Stop with your feet a few inches off the floor, knees still at 90 degrees, ready for the next rep.

What Are the Key Form Cues?

• Roll the pelvis, do not lift the legs: think of peeling your tailbone off the mat so the abs, not the hip flexors, drive the movement.
• Press your palms into the floor: the hands anchor the upper body so the hips are the only thing moving.
• Keep your shins parallel to the floor through the whole rep; a changing knee angle means the hip flexors have taken over.
• Exhale hard as the hips lift to flatten the ribs and shorten the abs harder at the top.
• Lower the hips onto the mat before the knees start to travel away.

What Are the Most Common Mistakes?

• Swinging the legs to lift the hips: momentum from the thighs carries the pelvis up and the abs only catch the weight at the top, so slow the rep and start the lift from the tailbone.
• Letting the feet touch the floor between reps: the abs unload and the lower back arches off the mat before the next lift, so keep the feet hovering.
• Arching the lower back as the legs travel away: the lumbar spine extends under the weight of the legs and the hip flexors take the load, so shorten the range until the back stays flat.
• Pulling with the arms: pressing the hands down turns into pushing the hips up, so keep the palms flat and the elbows straight.
• Rushing the descent: the eccentric is where the lower abs work longest, so take two seconds to uncurl.

What Are the Best Reverse Sit-Up Variations?

• Bent-knee reverse crunch with feet down between reps: the regression for lifters who cannot keep the feet hovering.
• Straight-leg reverse sit-up: legs extended toward the ceiling lengthen the lever.
• Reverse sit-up with hip lift: press the feet toward the ceiling at the top so the hips leave the floor fully.
• Single-leg reverse sit-up: one leg curls while the other hovers, for lifters who twist through the pelvis.
• Bench reverse crunch: the same curl on a flat bench, with the legs free to drop below hip level.

How Do You Progress the Reverse Sit-Up?

• Add load by holding a light dumbbell between your feet once you complete every set at 20 clean reps.
• Add 2 reps per set each week, working from 10 up to 20.
• Add one set per session, up to 4, before adding reps again.
• Slow the lowering phase to three seconds, or straighten the legs, once 20 controlled reps feel easy.

How Should You Program the Reverse Sit-Up?

Program the reverse sit-up at the end of a lower body or abs session, after squats, deadlifts or any loaded trunk work. Use it two or three times per week for 3 to 4 sets of 10 to 20 reps with 45 to 60 seconds of rest between sets. Pair it with a plank or a dead bug so the abs also resist extension in the same session.