Masters, or when I was a junior athlete, was called veterans and it was 45 for men and 40 for women. In Australia now it is 30!!! I retired from open athletics at 33.
Have to think the 40+ is masters. Even now you have some open athletes competing until late 30’s so I think there is argument to make it 45.
I would probably be considered a crap athlete, but I don’t care.
My brother, i think he just turned 39, 38 at youngest, just completed the Coolangatta Gold iron man race. Its a 4-5HR life saving race. (like a triathlon, but with paddle boards and ski’s also) He competed in the opens race. Mind you, had he been in the 30 - 39yrs age group, he would have been competitive.
Then again, the guy who came 2nd overall, he too was 39!
The mens 30+ 100m record is not too bad, faster than any athlete in australia can or has run.
I’d say 9.84 (Bruny Surin, Seville) is better than not bad.