Are you using crunches and sit-ups for training your clients' cores? If so, you may be harming them more than helping them! This goes double for if they suffer from lower back pain. But these exercises will help you not only strengthen their core, but their spine as well! Read the full article The Best Core Strengthening Exercises To A Healthier Spine: http://www.theptdc.com/2015/01/the-best-core-strengthening-exercises-to-a-healthier-spine/