Crunch

Which muscles does it train?

Equipment needed

How to perform it

Time under tension matters more than load here: 3 to 4 sets of 8 to 15 reps, or holds of 20 to 60 seconds, with 45 to 90 seconds of rest.

Execution and technique cues

• Lie on your back with feet flat on the floor hip-width apart and hands placed loosely behind the head without interlocking the fingers tightly.
• Gently press the lower back into the floor and engage the abdominals before initiating the movement.
• Lift the upper back by flexing through the thoracic spine, drawing the ribs toward the hips without pulling the head forward with the arms.
• Lower under control until the shoulder blades almost touch the floor and begin the next rep without using momentum.

Common mistakes

• Pulling the head forward with the hands, which stresses the cervical spine and takes tension off the abdominals.
• Lifting the entire back off the floor and turning the crunch into a sit-up, recruiting the hip flexors instead of the rectus abdominis.
• Using momentum and rushing through each rep rather than maintaining muscular tension throughout the full range of motion.

Frequently asked questions

What is the difference between a crunch and a sit-up?

In a crunch, only the upper back lifts off the floor to roughly the shoulder blade line while the lower back stays down. In a sit-up, the entire torso rises to an upright position, which also involves the hip flexors to a greater degree.

Should I add weight to make crunches harder?

Yes. Holding a weight plate or dumbbell at the chest is a straightforward way to add progressive overload once bodyweight crunches become too easy. Maintain the same controlled technique regardless of added load.

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