Prizefighting is a young man’s vocation. Such qualities as reflexes, speed and physical endurance all decline sharply with age. Physical diminishment that might be imperceptible among the regular population can be cruelly obvious within the ring.
The typical fighter is past his prime by his early 30s.
At the same time, boxing is a sport of tremendous skill. It’s not uncommon to see a wily, experienced veteran knock off a ferocious young lion. There's a sweet spot for a few years when skill peaks and physical abilities endure.
But there is a shelf life on even the finest talent. It's a rare few fighters who manage to keep excelling at this brutal sport past 40.