Polo Rules

Does this basically mean you can use forearms if you push with you body and not extend your arm?

It looked like a push from where I was, you both seemed pretty stationary at the time. You did get on with the game though.

You are allowed to push, as long as the elbow isn't extended more than 90 degrees (as Snoops states). It is fairly hard to get much force into that motion, if your arm isn't bent more than 90 degrees.