Your workout isnt as effective as it could be. Try adding some resistance- hold a dumbell at the top of your head while you do your crunches. You should be using enough weight that you reach muscle failure in 7-12 reps. Go for 3-5 sets. You might also want to try adding resistance by doing your crunches on an incline. Right now you're working your transversus abdominus and your obliques but you also should work your rectus abdominus to help get that six pack. Reverse curls with resistance will do that. [link|http://www.netfit.co.uk/abd8.htm|http://www.netfit.co.uk/abd8.htm].

If you hold a dumbell between your feet when you do this, it's really effective.

Also, all that ab work compresses the disks in your spine. You should also add some back extensions to bring them back to neuteral. You work the front, you gotta work the back.

[link|http://www.rice.edu/~jenky/sports/back.extension.html|http://www.rice.edu/...ck.extension.html]