system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do Olympic athletes who play a sport that doesn't have professional leagues (fencing, rhythmic gymnastics, etc) practice and train year round?

If they have to take a regular job to pay the bills. Or are they sponsored by a sports organization or their national Olympic committee? Is performance abilities in those less commonly watched sports stunted because athletes aren't playing and training every day like those with professional leagues or prize money?
gpt
To correct you on the misconception, all the sports in the Olympics have leagues but its not televised (if at all) like what most Americans are use to (i.e. NFL, NBA, and MBL). 

These leagues (fencing and etc.) are funded through 4 main sources: 

* Industry advertisement/sponsorship. 
* The association of the sport pays for some of it (each sport has an association that organizes these competitions)
* Competitors paying entrance fees
* Audience fees.

>If they have to take a regular job to pay the bills. 

It really depends on the country but generally yes they take a regular while doing this. In some cases the regular job is just an offshoot of their training (coaching) or completely unrelated (waiter). 

>Or are they sponsored by a sports organization or their national Olympic committee? 

Again really depends on the country. For example, China provides a lot of amenities for their athletes. 

>Is performance abilities in those less commonly watched sports stunted because athletes aren't playing and training every day like those with professional leagues or prize money?

No! They play and train as much as any other professional athlete. 

edit: If an Olympic athlete gets popularity they can also get income through additional sponsorships and advertising deals (whats common for USA athletes).