Huffington Post:

It is safe to say Michael Phelps has no need for a lifeguard watching over him in the Olympic pool but the most decorated Olympian of all time, with 18 gold medals among his career haul of 22, will have one anyway at the Rio Games.

And so will the rest of the world’s greatest swimmers in a situation that has caused some mirth in the run-up to the competition.

I saw this when the swimming events began and thought, why are they there? Now it makes sense.