I don't know what else to call it. Lately I've been seeing people, mostly alone, walking along pavements or standing in a public space just "fighting" nothing, like punching and kicking the air.

They don't seem aggressive, just methodical, like they are practicing for something. I've seen people of all ages doing it, some more subtle than others. Nobody else seems to bat an eyelid, which makes me wonder is this from a film or something? Is it a fitness craze? It's just plain weird I reckon.