Although, to kind of play Devil's advocate... Remember the greenhorn on the Northwestern two years ago? He showed up, took the shit, worked his ass off, and did all that he could to fit in and impress the crew. He even took a hit from Matt. At the end of the season, Sig gave the kid the jacket off his own back. That's badass. Funny thing is, before signing on the Northwestern, the kid was just a skater punk in CA.
So it's possible that attitude can make up for a lack of physical strength. But you have to have an abundance of at least one or the other.