This is the most commanly used abdominal exercise in the gym today. Crunches are super isolation exercises for the entire rectus abdominis as well as the intercostals
How to do:
1. Lie flat on your back and place your calves on a flat bench
seat. Your hamstrings should be perpendicular to the floor.
2. Place your hands behind your head with fingers interlaced
together.
3. Perform the following movements simultaneously: a. Pull your hips from the floor using your lower
abdominal muscles. b. Raise your shoulders and back from the floor using
your upper abdominal muscles c. Force your shoulders in moving them toward your hips d. exhale hard
4. Hold the contracted position for a slow count of 1-3 seconds.