I have been training for years now (triathlon). I come from a cycling background and used to be a competitive runner (above average). Here is my problem and any suggestions would be helpful.

Diet is good. Body Fat is low (sub 10%). Training is on par.

I just can't seem to put together hard workouts on a consistent basis. I can come out of the gate hard, crush it for a few days and then be wiped out for a week. I'm tired of getting my ass handed to me by guys that I used to wax the floor with and I am always wondering how these guys can put together solid weeks of training without any missteps!

I am coming to the conclusion that most of my competitors are using something. What am i missing and what suggestions do you guys have for a athlete that wants to get back to being on top?