Some Olympic sports belong to the young. Of the 15 U.S. Olympians who are 18 or younger, five are easily recognized—they're the Fab Five. No? Jalen Rose complained? OK, fine—"Fierce Five."
But we have a lot of turnover in gymnastics, so we can't exactly expect the Fab/Fierce/Fantastic Five to be back in four years.
Other sports have repeat Olympians. You don't need us to tell you gold medalists Alex Morgan (age 23), Missy Franklin (17) and Claressa Shields (17) have a good shot to do it again in 2016.
You might need us to remind you that Katie Ledecky, absolutely the youngest athlete on Team USA at age 15 (not 15.5, like Kyla Ross), also is taking a gold medal home from London.
And a lot of athletes made an impression in London without picking up a gold. Yet. Keep an eye on these athletes over the next four years, and remember their names when the cameras move to Rio.