Well I'm a 65 year old guy in good shape and still playing competitive volleyball and softball, I call them Awesome and the perfect specimens of athletic form.
With that being said, consider Michael Phelps' likely 20 years, if not more, training in a 100 meter cage.....back and forth, back and forth, back and forth, for how many laps, maybe a million or more?
To keep that focus for so many years is in itself a phenomenal accomplishment.............
Especially in view that he has ADHD. So it took and overwhelming type of activity to calm his mind and allow him to focus. That is one of the hallmarks of ADD/ADHD -- lots of scattered attention/energy and wasted opportunities, interspersed with laser focus on specific areas.