Well this sure is an interesting topic, isn't it?Story: So i was biking my way home from school on the sidewalk, and theirs a few small bumps, so why not go pretty fast, right? WRONGI hit one and it turned my handle bars all the way around, and then it tipped. I was sent off my bicycle a bit and landed on the concrete. I was smart enough to twist my head, so the side of my head is scraped and bloody, plus my right hand and an area around my collarbone. I was going roughly 8-11 miles an hour so, yeah.So the question i would like answered, is how fast you have to be going and hit your head for a concussion. i already saw a thread about someone recently having a life threatening concussion, which is not mine, but for any. Thank you.