Crunch
CoreIsolationCoreBodyweightBeginner
The classic floor ab exercise. Isolates the rectus abdominis with a short trunk flexion while keeping the lower back on the floor.
Visual guide
Reference photo — start and end of the movement.
How to perform
- 1.Lie on your back with knees bent and feet flat.
- 2.Bring your hands to your chest or the sides of your head.
- 3.Lift your shoulders, curling your trunk toward your knees.
- 4.Squeeze your abs at the top and lower under control without fully resting on the floor.
Common mistakes
- ●Pulling on the neck with your hands
- ●Lifting the entire lower back off the floor
- ●Using momentum instead of contraction
- ●Dropping back down without control
Proper technique
The movement is short: only the shoulder blades leave the floor. Keep your chin off your chest. Exhale on the way up and squeeze your abs.
Variants
Other exercises that work the same primary muscle.
muscle map
primary
secondary
Primary
- Rectus abdominis
Secondary
- Obliques
- Transverse abdominis