Plus, trying to do too many at once can cause pain or injury. The best thing for you is to master the basic crunch techniques ...

Of all the abdominal exercises, the basic crunch is one of the most effective. The key is to keep the movement slow and to focus on good technique. Lie on your back with your knees bent ...

This combo also delivers a simple, effective workout. "The basic crunch is often demonized but it's a great move to isolate the abs and focus on core stability," she says. "By pressing your heels ...