The phrase "stomach crunches" refers to a specific exercise that helps strengthen the muscles in your abdomen. It involves lying on your back, bending your knees, and lifting your upper body towards your knees. Full definition
Even if you've dropped most of your baby weight and you religiously do stomach crunches, that bulge around your belly doesn't seem to budge. (parents.com)
Yes, you heard right: Countless stomach crunches won't necessarily get you ripped, according to Lowery. (inc.com)
These include stomach crunches and sit ups. (babygaga.com)