It kind of makes sense. You can get your feet higher if you pull yourself into a ball, but that pulls the upper half of you towards the lower half so your center of gravity stays approximately the same, while making you A: more aerodynamic, probably but that's mostly irellevant and B: Less likely to hit the edge of whatever you're trying to reach. However it's more applicable to being, say, thrown by a catapult. You curl into a ball and so you're less likely to hit something, that something being the ledge you're trying to reach. Considering, however, how much of a benefit it gets you in source games and how fast you curl into a ball, it's a bit unrealistic there. Blockheads don't crouch, really, they lay down and crawl, though, so it's different in that way.
Anyways I will stop bothering you all with science about stuff that probably doesn't add up or something. I haven't taken physics yet but I have some understanding of it. (Mostly orbital physics and stuff, blame KSP. How can people who don't understand physics play that? It's a really serious game if you want to actually get to another planet, even if you don't want to come back.)