Alex seems to be remarkably resistant to skinned knees - I think he's done it once and even then it wasn't terribly major. A few other scrapes and scratches and a healthy harvest of bruises but not much else (other than the time he cracked his head climbing onto one of those irritating rides they have at the supermarket and developed an impressive goose egg on his forehead).

On the other hand he's also a little more restained than most of the kids I see (like Pipp or even James) and doesn't tend to throw himself into things without considering first if it's safe. This was quite apparent at his party when he bounced less energetically on the castle than all the other kids (still had a whale of a time, just less gung ho) and when he spent an afternoon throwing himself off a platform and onto a rolled up futon with Pippa - she launched herself arms spread wide, he tended to come down more carefully with his arms out to catch himself.

Still, if my knees are anything to go by he'll probably still manage plenty of scraped knees as time goes by.