Have you ever hyperextended an elbow while working out? Basically, this is when your elbow bends too far back. I came close recently. Luckily I stopped what I was doing and took some time off. Even push ups hurt after that. I can't imagine actually hyperextending it though. It's gotta hurt so bad. You also have to watch out when watching weight lifting videos online because there are some idiots out there who do this by accident on video.