Yes, it's true. These two standard ab exercises can actually be murder on your low back. (But I have 3 solutions below...)
Why are they bad?
Because they involve spinal flexion (rounding your lower back to allow you to bend forward at the waist). But according to research, that's the exact mechanism that causes a herniated disc in your lower back.
After all, most people "throw their back out" bending over to pick something off the ground - during spinal flexion.
So it makes sense to limit the amount of traditional sit-ups and crunches in your program.
Plus, you can't spot reduce the fat from one area, so you are better off spending that exercise time on a better total body exercise or intervals. If you want to flatten your abs, you need to lose body fat.
So to improve your abs, use the 3 following techniques:
1) Take half the time you were spending on abs, and spend that time on intervals instead.
2) Spend the rest of your ab training time doing total body ab exercises and total body workouts including exercises that work your abs such as...
- DB Renegade Rows
- Spiderman Pushups and Decline Spiderman Pushups
- Pullups with Knee-ups
- Spiderman Pullups
3) Keep your abs braced in all exercises so that you work your abs in every movement that you do.
Train hard but safe,
Craig Ballantyne, CSCS, MS