The tuck up is a bodyweight abdominal exercise performed lying flat that trains the rectus abdominis and hip flexors by folding the shoulders and knees together into a tight ball. Unlike the seated knee tuck, where the hands fix the torso and only the legs move, the tuck up starts from a hollow position with arms overhead, so the upper body lifts off the floor as the knees come in. The range runs from fully extended to fully folded, which doubles the distance the abs shorten. Calisthenics coaches program it as a core opener or finisher.
What Muscles Does the Tuck Up Work?
- Primary: Rectus abdominis, iliopsoas (hip flexors)
- Secondary: Obliques, rectus femoris, tensor fasciae latae
- Tertiary: Serratus anterior, anterior deltoid, adductors (holding the knees together)
How Do You Set Up for the Tuck Up?
Lie on your back on a mat with your legs straight and together and your arms extended overhead, biceps beside your ears. Press your lower back into the mat by tucking your pelvis and pulling your ribs down. Raise your heels and hands a few inches off the floor so your body forms a shallow hollow curve. Point your toes and hold the tension before rep one.
How Do You Perform the Tuck Up?
- Set the hollow with your lower back pressed into the mat, heels and hands hovering.
- Fold at the hips and the ribs together, lifting your shoulders off the floor while your knees drive toward your chest.
- Balance on your tailbone with your shins parallel to the floor and your hands reaching past your knees, which tells you the fold is complete.
- Squeeze the ball tight for one second, pulling your knees and chest an inch closer.
- Open slowly over two seconds, reaching your arms back overhead and your legs long at the same speed.
- Stop in the hollow with heels and hands still hovering, then start the next fold from there.
What Are the Key Form Cues?
- Close like a book: Send the chest and the knees toward each other at the same moment so neither the legs nor the torso arrives first.
- Keep the lower back heavy in the open: Feel your lumbar spine pressing into the mat as the arms and legs reach away, which is what protects the hollow.
- Reach the fingertips past the shins at the top rather than grabbing the knees.
- Lead the return with the arms and legs, not by rolling the spine down.
- Exhale hard through the fold and inhale as you open.
What Are the Most Common Mistakes?
- Opening too far between reps: Letting the heels and hands touch the floor drops the tension and turns the exercise into a sit-up, so keep both hovering.
- Throwing the arms for momentum: Swinging the hands forward yanks the torso up so the abs never flex the trunk, so move the arms at the speed of the legs.
- Arching the lower back in the open position: Losing the hollow with the limbs extended loads the lumbar spine under their full lever, so shorten the range until the back stays pressed down.
- Tucking the chin to the chest: Pulling the head forward strains the neck and fakes the trunk flexion, so keep the gaze toward the knees.
- Kicking the legs in first: Leading with the hip flexors leaves the abs idle, so fold from the ribs first.
What Are the Best Tuck Up Variations?
- Hollow hold: Hold only the open position to build the hollow before adding the fold.
- V-up: Keep the legs straight through the fold so the lever is longer and the hips flex further.
- Alternating v-up: Reach one hand to the opposite foot so each rep loads one side of the trunk and the obliques.
- Tuck up with knees offset: Pull both knees toward one shoulder to shift the work onto the obliques.
- Kettlebell v-up: Hold a light kettlebell in both hands overhead to add load through the whole range.
How Do You Progress the Tuck Up?
- Move from a bent-knee tuck up to a straight-leg v-up once every rep balances on the tailbone without rocking.
- Build from 8 reps up to 15 per set before lengthening the legs.
- Add a fourth set once three sets of 15 are clean.
- Slow the opening phase to four seconds, or hold the folded position for three seconds, once the reps feel easy.
How Should You Program the Tuck Up?
Program the tuck up as a core finisher after your main lifts, or as an opener on gymnastics days before hanging work. Train it two to three times per week for 3 to 4 sets of 8 to 15 reps, resting 45 to 60 seconds between sets. Pair it with a hollow hold or a plank so the abs also practice holding the position they move through.