Ouch!

So today during PE, my class was playing volleyball. Me and my other friend were bored and we started talking about how we both did karate for a while and then we quit. I was pretending to kick him and he told me a move where he would catch my foot with his hand and then use his foot to attack my other foot, knocking me off balance and making me fall. So i argued that i could just use my two hands to keep my balance against the floor, upside down. He tried the move on me and...... i fell :(. I fell on my knee that had a still- healing wound too! When i got up, many people asked if i was okay. Apparently i had made a very loud THUMP as i hit the floor. xD