My parents sent me to every sports club going

[Maybo]

Like her husband, Sarah's love of being active began at school. "My parents sent me to every sports club going," she says.
(Hello!Magazine)

Does “going” mean “operating”?

 

[Rover_KE]

Yes.

 

[emsr2d2]

Yes, but bear in mind that we use the phrase in a way that it's not always possible to replace "going" with another continuous verb.

I've seen every Tom Cruise film going. (going = that exists)
He drank everything going. (going = that was available)
She plans to use every bit of gym equipment going. (going = that's in the gym for people to use)

 

[jutfrank]

I think if you're going to choose just one word to help you understand the meaning, it's 'available'.