Solarpunk technology

I've also had this same idea more than once.

I think the power output of the earlier commentor is probably for a "basic" fit person. But what about those huge bodybuilding hulks? How much is the power output when they're pulling maximums for a day?

In the best scenario, there'd actually br extra electricity to sell back to the grid, and the gym might be free for some of the "power-users".

However I think as the earlier dude points out, stable power output isn't that high and probably way more reliable to just put down solar panels, and a whole gym worth of generative weight lifting equipment would probably cost quite a lot.