"... finding new ways.Change is what evolution is all about,isn't it?"

Evolution is about change in genetic populations, not physical changes in individuals.

"And I don't think great athletes become great because of gatorade or their so called improved training."
I think you underestimate the importance of diet and training. It's not just that athletes train hard. Athletes have always trained hard. It's that they are training scientifically. We actually know a lot more about how to exercise now. Specific exercise programs can target specific muscles that are used for strength or for fine motor control.

I used to think that Personal Trainers were a waste of money. That was till I actually tried one. I got a membership at the county rec center and got to meet with a trainer for free. It was amazing the experience and insight I was getting from this guy. I'm now a big believer in PTs. (Unfortunately, not all of them are equally good.)

"But my point is training and diet I think has limits. And new world records in athletics are constantly being made."

It's a good point. Training and diet *do* have limits, but our understanding of these has improved dramatically over the last 50 years - and it looks like it will continue to improve for another decade or so. I doubt we have yet seen the limits that diet and training can produce.