Suitcase Crunches: Muscles Worked, How To and Variations

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A suitcase crunch folds a regular crunch and a reverse crunch into one movement, closing your body like a suitcase.

It trains the upper and lower regions of your rectus abdominis, your hip flexors, and your obliques in a single rep.

If you want more from a crunch than a crunch gives you, this is the move.

Muscles Worked: What Suitcase Crunches Actually Train

A suitcase crunch hits two ab regions and two sets of hip flexors at once. Here is what actually does the work.

Primary movers

Rectus abdominis (upper region) flexes the spine. This is the shoulder-lift half.
Rectus abdominis (lower region) works harder than in a standard crunch because your hips also move. The knee-in half recruits these fibers directly.
Hip flexors (iliopsoas: iliacus and psoas major) drive hip flexion as your knees travel toward your chest.
Rectus femoris is a quadriceps muscle that crosses the hip. It assists hip flexion on the closing phase.

Secondary stabilizers

Obliques (internal and external) brace against lateral shift and fire harder on rotational variations.
Transverse abdominis (TVA) is your deep bracing muscle. Activation climbs with forced exhalation, per ACE’s core training guidance.
Tensor fasciae latae (TFL) is an outer-hip stabilizer that assists hip flexion.
Adductors engage when you keep your feet uncrossed.

One popular article lists rectus femoris as a core muscle. It is not. The rectus femoris is one of the four quadriceps.

Its only relevance here is that it crosses the hip joint and acts as a hip flexor. It belongs in the hip-flexor bucket, not the ab bucket.

How to Do a Suitcase Crunch

What you need: a mat.
Optional: a dumbbell, kettlebell, plate, or medicine ball once you have mastered bodyweight.

Lie flat on your back with legs fully extended and arms stretched overhead. This is the open-suitcase position.
Press your lower back into the mat and pull your belly button in. This locks a posterior pelvic tilt and switches off your hip flexors so abs have to do the work.
In one motion, sweep your arms up and forward while bending your knees toward your chest.
Crunch your shoulder blades off the mat (not just your head) as your knees come in. Hands and knees should end near each other above your torso.
Pause one count at the top. Squeeze your abs.
Reverse under control. Slowly extend your legs and bring your arms back overhead.
Do not let your hands, heels, or weight touch the floor between reps. Keep constant tension.
Exhale forcefully as you close. Inhale as you open.

Form cues to lock in:

Shoulder blades up, not just head.
Lower back flat to the mat throughout.
Feet uncrossed to engage adductors.
2 to 3 seconds down, 1 second up. No swinging.

Nail the bodyweight version first. Now here is every mistake that keeps you from feeling it in your abs.

Common Mistakes (and How to Fix Them)

If you feel this exercise in your neck, hip flexors, or lower back instead of your abs, one of these six mistakes is almost always the cause.

Swinging the legs with momentum

Reps feel effortless and hip flexors fatigue first. Fix: slow the eccentric to 2 to 3 seconds and pause in the open position. Abs, not legs, initiate the knee-in.

Pulling on the neck

Neck gets sore before abs fatigue. Fix: keep hands beside your ears, not behind your head. If pain continues, leave your head on the floor and perform only the leg-and-arm portion.

Losing lumbar tension at the bottom

Lower back arches off the mat in the open position. Fix: press your lower back into the mat throughout and think posterior pelvic tilt at the bottom.

Feeling it only in the hip flexors

Hip flexors burn but abs do not. Fix: brace first, then curl. Drive from ribs-to-pelvis shortening, not knees-to-chest. If it persists, regress to knee tucks.

Rushing into a swing

Each rep should feel like two deliberate crunches folded together. Fix: 1-second pause closed and 1-second pause open.

Adding weight too soon

Fix: hit 3 sets of 20 bodyweight reps with perfect form before you touch a dumbbell. Load exposes form flaws. It does not fix them.

Fix these and you will feel your abs do the work, which is the point.

Benefits of Suitcase Crunches

Suitcase crunches are worth doing, just not for the reason most articles claim. Real benefits first, then the honest myth-bust.

Train upper and lower rectus abdominis in one move: Shoulder flexion plus hip flexion fires both fiber regions in the same rep.
Time-efficient: One exercise replaces a crunch plus reverse crunch pair. Coach Levi uses it for that reason.
Scales from bodyweight to loaded: Bodyweight, dumbbell, kettlebell, plate, or medicine ball. The tool matches your level.
May support lower back health: Two PubMed systematic reviews (PMC5648929 and PMC4395677) found core-strengthening work, including crunch variations, can reduce and prevent lower back pain by strengthening the rectus abdominis and transverse abdominis.
Improves hip flexion range of motion: The closing action builds hip mobility, a secondary back-health win.

Now the myth-bust. “Suitcase crunches isolate the lower abs” is marketing, not physiology. The rectus abdominis is one long muscle that contracts as a unit.

You can bias emphasis toward the lower region with hip flexion under resistance, which is what the reverse-crunch half does. You cannot isolate a slice of one muscle.

Suitcase crunches do recruit lower fibers harder than a standard crunch. Whether those fibers show depends on body fat, not exercise choice.

Variations and Progression Ladder

The suitcase crunch scales further than most ab exercises. Here is the ladder from absolute beginner to advanced.

Knee tucks (flat back). Lie flat, legs in tabletop, arms by your sides. Draw knees to chest. Move up when 3 by 15 feels easy.
Bodyweight suitcase crunch, tabletop start. Legs in tabletop, arms overhead, close to the suitcase position. Move up at 3 by 15 clean reps.
Full bodyweight suitcase crunch. The canonical version from section 4. Legs fully extended, arms overhead. Move up at 3 by 20 with perfect form.
V-sit suitcase crunch. Balance on your glutes with back and feet six inches up, then close and open under constant tension. Move up at 3 by 12 without feet touching.
Alternating suitcase crunch. Add rotation: one knee and the opposite elbow meet, bicycle-crunch style from the V-sit. Move up at 3 by 10 per side.
Weighted suitcase crunch. Dumbbell, kettlebell, or plate overhead. Start 5 to 10 pounds, progress in 2.5 to 5 pound jumps.
Hanging knee raises. Coach Horton’s graduation point. Same lower-ab emphasis, bigger demand, less back load.

Equipment notes:

Dumbbell: easiest to progress in small jumps. Home-gym friendly.
Kettlebell: offset mass adds shoulder demand.
Medicine ball: hold overhead, or squeeze between your ankles to force adductor work.
Weight plate: precise increments, but hard edges can bother wrists.

Suitcase Crunch vs. Regular Crunch vs. V-Up vs. Reverse Crunch

If you are staring at four similar-looking ab exercises wondering which to pick, here is how they actually differ.

Exercise	Primary movers	Secondary movers	Range of motion	Difficulty	Best for
Regular crunch	Rectus abdominis (upper emphasis)	Obliques	Short (shoulders only)	Beginner	Learning ab engagement, low-volume finisher
Reverse crunch	Rectus abdominis (lower emphasis), hip flexors	Transverse abdominis (TVA)	Short to medium (hips only)	Beginner to intermediate	Isolating the hip-flexion component, rehab-friendly
Suitcase crunch	Rectus abdominis (full), hip flexors	Obliques, TVA, adductors	Long (both ends meet)	Intermediate	Trainees who want both crunch patterns in one move
V-up	Rectus abdominis (full), hip flexors	Spinal erectors (stabilizing)	Longest (back leaves floor)	Advanced	Dynamic core strength, athletic carryover, V-sit prerequisite

The suitcase crunch sits between the simple crunch and the athletic V-up. Its edge: it trains the full rectus in one move without asking you to balance on your butt.

Regular crunches are easy and have the least range of motion. Good as a warm-up.

Reverse crunches are a smart pick if hip flexors dominate your other ab work, a point Matt Claes at Weight Loss Made Practical has made directly. V-ups are the step up from a suitcase crunch.

Do suitcase crunches 2 to 3 times a week, and pair them with a reverse crunch or a plank for anti-flexion balance.

FAQs

What muscles do suitcase crunches work?

Primary movers are the rectus abdominis (both upper and lower fiber regions) and the hip flexors (iliacus, psoas major, and rectus femoris).

Secondary stabilizers include the obliques, transverse abdominis, tensor fasciae latae, and adductors (when you keep your feet uncrossed).

Rectus femoris is a hip flexor and quadriceps muscle, not a core muscle, despite what a few articles say.

How many suitcase crunches should I do?

It depends on your goal. Beginners should start with 3 sets of 10 to 12 bodyweight reps. For hypertrophy, do 3 to 4 sets of 8 to 15 reps with weight.

For conditioning, aim for sets of 20 to 25 reps and 100 to 150 total across a circuit. Frequency: 2 to 3 times per week is the sweet spot for most goals.

Are suitcase crunches bad for your back?

For healthy lifters with no disc disease, suitcase crunches are low-to-moderate risk when you control the tempo and keep volume reasonable. For people with disc herniations, active lower back pain, or degenerative disc disease, flexion under load is a real concern.

What is the difference between a suitcase crunch and a V-up?

In a V-up, your back leaves the floor and your legs stay straight. It is a full-body hinge. In a flat-back suitcase crunch, your lower back stays pressed into the mat and your knees bend.

V-ups are harder and demand more from the hip flexors and spinal stabilizers. Suitcase crunches are more accessible and let you keep the back supported.

Can I do suitcase crunches every day?

You can, but you should not. Your abs recover like any other muscle, and 2 to 4 sessions per week is plenty for both growth and endurance.

Daily 100 to 150 rep protocols exist (some college football programs use them), but that is a specific athletic conditioning block, not a default. If abs feel sore or sluggish, take a day off.

Bottom Line

Suitcase crunches earn a spot in your core routine if you want more from a crunch than a crunch.

They train both regions of the rectus abdominis, scale from bodyweight to loaded, and need only a mat.

They are not magic. No crunch carves visible abs without nutrition, and they are not for everyone.

Do them if: You are an intermediate lifter who wants a more complete crunch, or a home-workout enthusiast with limited equipment. Start with 3 sets of 15 bodyweight reps.
Skip them if: You have disc issues, are past 12 weeks pregnant, or have unresolved diastasis recti. Use dead bugs, bird dogs, and side planks instead.
Start here: Bodyweight, 3 sets of 12, 2 to 3 times per week for two weeks. Then add a light dumbbell overhead. Fix your form before you fix your load.