How to do a Crunch
The crunch is a floor exercise where you curl your shoulders off the ground by bringing your ribcage toward your hips. It targets the rectus abdominis, the six-pack muscle at the front of your midsection. It needs no equipment and is a simple starting point for beginners building core strength.
- Primary muscles
- Abs (rectus abdominis)
- Also works
- Obliques
- Equipment
- Bodyweight, Exercise mat (optional)
- Level
- Beginner
Step by step
- Lie on your back with your knees bent and your feet flat on the floor about hip-width apart.
- Cross your arms over your chest or rest your fingertips lightly behind your ears with your elbows out wide.
- Exhale and tighten your abs to curl your head, shoulders and upper back off the floor.
- Lift until your shoulder blades clear the ground, keeping your lower back in contact with the mat.
- Pause for a second and squeeze your abs hard at the top.
- Inhale and roll back down slowly until your shoulders touch the floor.
Coaching cues
- Think about shortening the distance between your ribs and your hips, not sitting all the way up.
- Keep a fist-sized space between your chin and chest.
- Move slowly; quality reps beat fast, sloppy ones.
Common mistakes
Pulling on the neck
Let your hands only support your head and lift with your abs instead.
Using momentum
Slow down and pause at the top so the abs do the work on every rep.
Sitting up too high
Stop once your shoulder blades leave the floor to keep tension on the abs, not the hip flexors.
Sets and reps
Strength
3–4 sets of 8–12 slow reps holding a light plate
Muscle growth
3 sets of 12–20 reps
Endurance
2–3 sets of 25–30 reps
Alternatives
FAQ
Are crunches good for building abs?
Yes. Crunches directly train the rectus abdominis, and adding weight or slower reps over time helps it grow. Visible abs also depend on overall body fat levels.
Are crunches bad for your back?
For most healthy people, crunches done with control and a modest range of motion are fine. If they cause discomfort, try a plank or other core exercises and check with a qualified professional.
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