The context of the following conversation is Sasha is an athlete.  She rides her bike everywhere, whenever possible.:
Sasha says I ride my bike everywhere.  It's the best workout..
The friend responds It's also great for the environment..
Sasha responds Yeah, we need to do everything we can to save the environment.  There's too much pollution, especially in this big city..
The friend responds You are such an athlete, you should join those cyclist that bike up the trails..
Sasha responds They are so hardcore.  I did that once..
The friend responds They are a tight community..