Recent evidence from a group in Scandinavia (or maybe the Netherlands?) suggests that a single regimen of testosterone based ergogenic aids results in muscle fibers splitting. They make a very compelling case that the benefits from that single regimen (I think it lasted 4 weeks), adds huge benefits (along with training) for 10+ YEARS. They propose that all doping penalties be for life, and I agree.

I've seen too many people end a career prematurely because they were unwilling to dope. Sad.