Crunches
What you'll gain
Isolates the abdominals through a short range with the lumbar spine supported.
Needs no equipment, so it fits any room, travel context, or beginner block.
Serves as the reference trunk-flexion clip that decline and weighted variants are compared against.
Step-by-Step Instructions
- 1
Lie on your back with your knees bent and your feet flat, heels about a foot from your hips.
- 2
Place your hands behind your head with the elbows open, or cross the arms on the chest.
- 3
Press the lower back gently into the floor and brace the abdominals.
- 4
Exhale and curl the rib cage toward the pelvis until the shoulder blades lift off the mat.
- 5
Pause with the lumbar spine still in contact with the floor.
- 6
Inhale and lower under control without dropping the head between reps.
Common Mistakes
Yanking on the head with the hands, which strains the neck and fakes trunk range.
Curling all the way to a sit-up, which hands the work to the hip flexors.
Lifting the lower back off the floor, which turns a short curl into a swing.
Racing the reps so the abdominals never stay shortened at the top.
About This Exercise
The crunch is trunk flexion done lying face up with the knees bent and the feet flat. Only the shoulder blades and upper back leave the mat; the tailbone and lumbar spine stay down, which keeps the work in the abdominals instead of handing it to the hip flexors. That short range is the point of the exercise. EMG work used the traditional crunch as the reference against which other ab moves were compared, and none of the gadgets beat it for rectus abdominis activity. For a catalog the floor crunch is the baseline abdominal clip. It fits beginner core blocks, bodyweight filters, and comparison pages that show why a crunch is not a sit-up.
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A short-range supine trunk curl that lifts the shoulder blades while the lower back stays on the floor.
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Compare our packs to find the right fit, all with commercial licensing included.
Specifications
Built for
- Baseline abdominal work in mobile app workout builders.
- Beginner core blocks that must run with zero equipment.
- Comparison content explaining crunch versus sit-up range of motion.
- Progression ladders from floor crunches to decline and weighted variants.
Muscles Worked
Details
License Includes
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