I would have posted this sooner, but I felt it was more appropriate to share this after the Games this year.
To understand how professional Olympic athletes fund their training and make any income, you need to learn more about Bylaw 3 of Rule 40 of the Olympic Charter. Please check out the articles below:
Birds Eye View: Rule 40 Explained
U.S. Olympic Committee’s Rule 40 is ridiculously restrictive on athlete’s sponsors
IOC’s Rule 40 has potential to be sponsorship game changer
How the Olympics’ New Advertising Rules Will Impact Athletes and Brands in Rio