Looking after your back

Okay I started in a gym when I was 16 years old, I did massive crunches, leg raises twists with a bar to get a really awesome 6 pack, okay I starved alot to see what they looked like.  Right now as a fitness instructor and coach I keep up to date with training information and what seems to have been a great idea before is now not so much.  Stuart McGill of Waterloo University has researched that the flexion of the spine is a limited supply.  Flexion of the spine puts wear on your back that can't be undone.  So revamp your core workouts, no more are you going to be doing crunches and sit ups, try some plank, try some core stability work.  I am going to post his link to my site so you can easily check it out.  When you know better, do better.