<human>: Provide a brief overview of the text.

This actually happened a couple years ago in 7th grade. 

So we had this chill teacher who would let us chill in her class room during recess if we didn't wanna head out. Well I live in Arizona so it would always get extremely hot outside and me and three of my friends just decided to stay in class and play catch in there, no one else really came in. Well one day the teacher left to go to the bathroom and once the door shut a lightbulb in my brain went off. I'm going jump off a chair do a sweet karate kick and land my feet in another chair. I don't know what made me think to do it but with the help of my friends I made a line chairs only about 5 long. Anyways i do a running sprint toward the chair to get more airtime and once I put my foot on the chair it moved throwing me off balance. I thought maybe I can recover so I jumped off of it, threw my leg in the air like they do in the karate moves except I didn't move my other leg and it caught the edge of the chair making me lunge forward face first in the middle of some chairs. I put my arms out to dampen my fall, my arms fall in between two chair I hit the ground absorbing all the shock with my left arm then as I was falling my face hit the seat part of the chair giving me a bloody nose. My teacher Walked back in at that moment to see me lying on the floor chairs around me, blood coming out of my nose, and my friend surrounding me asking if I was okay. 
I ended up breaking my ulna in 3 places and having to wear a cast for a long time and got my teacher in trouble, we couldn't chill in there for recess anymore and also have a tiny scar on my nose .
<bot>: tried to karate kick over some chairs and ended up breaking my wrist in 3 places and getting a small scar on my nose