Has anyone heard the story about how the "Muscles" nickname for Rosewall started? No?
Well, here it is.
In 1952, Rosewall and Hoad made their debut with the Australian Davis Cup team, which provided them with entrance and transport to the world men's tour.
Rosewall and Hoad were only 17 years old, and although Hoad enthusiastically joined Sedgman and McGregor in the strenuous weight-lifting and muscle-building exercises, Rosewall did not.
Anyway, Hoad himself invented the nickname "Muscles" for Rosewall, presumably because of these exercise routines. It was an ironic nickname, just as Laver would get the nickname "Rocket" because he was initially slow to react around the court.