You don’t need to do any crunches to get a flat belly.

You don't need to do any crunches to see 6 pack abs.

There are numerous problems with crunches.

First, crunches isolate one muscle group – the abs. Remember that in everyday living, the body works as one unit and it’s better to train it as such. Total body movements that work in multiple planes of motion are best.

Second, when you do crunches, you are lying on your back on the ground for part of the time, so your abs are relaxed and not even working during a portion of the crunch. You need to keep your abs braced as if someone was going to kick you in
the gut...at all times...suck up that gut, people!

Third, your abs play a critical role in stabilizing your spine (not flexing or bending it) and should be trained as such. During crunches, your abs are helping to flex the spine, not stabilize it. This will lead to a stiff neck and a sore back.

And finally, crunches are not an intense enough exercise to where you’ll be burning enough fat calories. Even if they did
work (which they don't), who wants to lay around wasting time doing endless amounts of crappy crunches?

So once and for all, crunches should be eliminated from your workout program. They suck. End of story.

If you REALLY want to get a flat stomach without ever doing another crunch (or back breaking sit-ups), you will love -

Mountain Climbers
Prisoner Squats
X Body Knee Ups
Spider Climbs
Mountain Steppers
The Almight Burpee
Plank Variations...and that is just a few.

If you are ready for real intense, effective ab/core/total body training experience - the way it was meant to be - then
Rock Star Boot Camp is your new home. :)