Crunch
Log this in the trackerThe basic abdominal curl: a short range, done properly, for the rectus abdominis.
What it is
Lying on your back, you curl the ribs toward the pelvis and lower again. It is a small movement, and the small range is the point: the abs flex the spine, they do not lift the whole torso.
Muscles worked
Primary: Core. Secondary: Obliques.
How to perform it
- Lie on your back with knees bent and feet flat, hands lightly by your temples.
- Press the lower back gently into the floor and breathe out.
- Curl the shoulders and ribs toward the pelvis until the shoulder blades leave the floor.
- Lower slowly without letting the head crash down.
Common form faults
- Pulling the head forward with the hands. Rest the fingers by the ears and keep a fist's gap between chin and chest.
- Sitting all the way up, which brings the hip flexors in. Stop once the shoulder blades clear the floor. That is the whole range of a crunch.
Programming
15 to 25 reps, or fewer with a plate held at the chest. Slow the tempo before adding reps beyond twenty-five.
Plan your training
Variations & substitutions
Frequently asked questions
- Do crunches burn belly fat?
- No. They build the abdominal muscles; the fat covering them comes off through an overall calorie deficit, not through the exercise choice.
- Crunch or sit-up?
- The crunch keeps the work on the abs. The sit-up adds hip flexion, which trains more muscles but is harder on the lower back for some.