If true. These two standard ab exercises, sit-ups and sit-ups, can actually be murder for your lower back.
Why? Because they involve flexion of the spine (rounding the lower back to allow you to bend forward at the waist). But according to research, that is the exact mechanism that causes a herniated disc in the lower back. After all, most people “turn their backs” when bending over to pick something up off the floor.
So it makes sense to limit the number of sit-ups and sit-ups in your program. Also, you can’t reduce fat from one area, so you’re better off spending that exercise time on a better full-body workout or intervals. If you want to flatten your abs, you need to lose body fat.
So, to improve your abs, use the following techniques:
1) Take half the time you used to spend on crunches and do intervals with that time instead.
2) Spend the rest of your ab training time doing resistance abdominal exercises, such as planks, side planks, mountain climbers, and variations of these exercises.
3) Keep your abs tight in all exercises so you work your abs with every movement you do.
For advanced bodybuilding, there will come a time when you need to do traditional abdominal movements. But it’s best, to get results (ie grow your abs) to do this with resistance. Cable crunches are good, and you can get results with a relatively small amount of spinal flexion.
But really, when it comes to getting great abs, losing body fat is the most important aspect for most people. And if you’re a desk jockey, it’s more important to you to have abdominal strength than to risk your back with classic ab exercises.