I've been holding off on posting on the issue of the relative safety of skateboarding because I have no background in statistics or medicine. In my own 22 years of skateboarding I have seen several broken bones--wrists and ankles--and innumerable bruises and scrapes... I have never seen a head-injury happen, outside lacerating my own forehead in a backyard pool in the 22nd year of my own skateboarding carreer. what a dope.
anyway, I want to share with you this research. Just click the word "this" in the previous sentence. It is significant, reliable, and typical of all the other results I've viewed.
The bottom line is, skateboarding in concrete parks is not as dangerous as basketball.
Another consideration I'd like to share is the strong possibility that skateboarding youth are less prone to repetitive stress injuries, since there are usually no parents or coaches pressuring them.
I worked with high school youth for years and it was sickening to watch adults pressure them into horriffic injuries. I saw a sixteen year old with his knee unzipped twice to repair destroyed ligaments--all for touchdowns. This kind of injury is quite rare in skateboarding; especially at that age.