Yeah I'm sure it's used a lot as an excuse when it's not the case, but it is definitely a real thing. When you're talking about amateur athletics, who gives a shit. But it's definitely important for the pros to peak at the right time.

I don't think it's a valid excuse, though. It's a sign of stupidity and/or imcompetence. A pro athlete - especially one with experience competing on the world stage - should know how to train by now.

It's like the inverse excuse of when guys say "oh I only lost because I wasn't in shape." Really? So you're lazy? No discipline? You don't take pride in your performance? Good to know, dummy.