I've been having a bit of trouble with my ab's lately...
For a long time I've been doing crunches on a machine, about 3 sets of 10 repetitions, starting at 130 pounds and increasing 5 pounds per set. This seems good for me, and I have a flat stomach and visible musculature.
I also do situps outside of the machine on an incline bench: 3 sets of 20 reps. Sometimes more.
(I weigh 140 pounds, and am 5 foot 11 inches tall.)
I do this almost every day, yet I don't have the level of definition I was hoping for. I have a "six-pack", but the developed muscles at times are difficult to see, and I would really like more definition then I have at the moment...
What could I do to further my ab development and increase my definition? Any other exercises I could consider? At times I suspect my muscles are getting too used to the exercise and getting lazy again!
Thanks in advance for all the useful tips that I may receive