How to do a crunch
The crunch is a short, controlled movement that trains your abdominal muscles. It is a simple core exercise that needs nothing but a mat.
Step by step
- Lie on your back with your knees bent and your feet flat on the floor.
- Rest your fingertips lightly behind your head, or cross your arms over your chest.
- Breathe out and curl your head and shoulders up until your shoulder blades leave the floor.
- Squeeze your abs at the top for a moment.
- Lower slowly back down and repeat.
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Common mistakes the coach checks
- Pulling on your neck. Keep a fist of space between your chin and chest; your hands only support your head.
- Not curling up enough. Curl up until your shoulder blades leave the floor.
- A little short. Squeeze your abs hard at the top of each crunch.
Sets and reps
Do 2 to 3 sets of 12 to 20 slow crunches. Slow, controlled reps beat fast ones.
Make it easier or harder
- Easier: Keep your arms by your sides and lift only your head and the tops of your shoulders.
- Harder: Hold a weight on your chest, pause at the top, or lift your feet off the floor.
Stay safe
Don’t pull on your head: keep a fist of space between your chin and your chest, and keep your lower back on the floor.
Check your form with the AI coach
Put your phone on the floor, 2 m to your side, in landscape — head to feet in the frame. Side-on I can see how far your shoulders curl up and whether you pull on your neck. Then press Start training and go: there's nothing to pick, the AI detects that you're doing crunches, counts your reps and tells you out loud when your form slips.
Start trainingJust counting? See the free AI rep counter.
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