You can look up the athlete bios for the US rowing team, some list non-sporting occupations - research asst, receptionist, sports psychologist, are the first few I saw. Others list graduate degrees in engineering, finance, accounting, etc. so it seems likely they are employed in those fields.
A couple other links that talk about the non-sporting jobs that Olympic athletes have. (And how little they make, in many cases.)
Do Olympic Athletes Get Paid? Job Description of an Olympian
What 36 Olympic Athletes Do For A Living - Business Insider
Olympic athletes face financial hardship - Jul. 10, 2012
As for gymnasts, if you check the bios of the national teams, the men at least are mostly college students. The women, as they are like 16-18 y/o, I guess there really isn't the opportunity to be employed or in college anyway.
I'm not sure if Rick is saying that a college athlete is equivalent to a professional athlete. Not being paid would seem like a meaningful distinction . . .