[altcognito]

So, I really did bounce back and forth on putting a qualifying "his best days are likely behind him". In an absolute sense, you will never have as many fitness "opportunity" as you did when you were 16-35. Speaking as an older dude who exercises a lot: Enjoy working out way, way harder than you should at a young age and getting away with it because your body is like a superhero with its recovery rate.

I didn't mean anything beyond pure athleticism. Sport is another matter.

Physically, it's much more tricky to train and become an at an older age. But I'll agree that for some folks, you can be a better version of yourself at earlier ages -- it is just dependent on what type of athlete you were then, and much permanent damage your body has sustained over the years.

I ran sub 17 5k at 18 years old. Will my tendons and knees support the kind of workload that is required to attempt that again?

One day, your body will fail. Even Tom Brady knows father time always, always wins. You have to choose your battles and figure out where you want to spend your time.

[Seanambers]

Measured in absolute peak performance wise, yeah you're right. He will never be an olympian. However most people don't have the opportunity to "discover" their physical ability at 15 nor at 25. So in other words : For most - if they start a regular exercise regime at 40 they will end up at the best shape of their lives.