Polo is the most reactionary (in Europe at least) with other equestrian events closely behind.

I’d say football (soccer for seppos) is the least reactionary, all it takes is:

• almost any space (a field ideally, but an road or alley or a yard etc is fine),
• a ball, (including a makeshift one made from plastic bags and twine),
• some goal makers (a T-shirt, rock, tree, painted bit of wall etc)
• and a mate

and you’re playing.

Water polo is brutal, I saw photos of competitors coming out of the water and it looked like their legs were attacked by piranhas