What's with the cave troll?

[Knight of Gondor]

In the books, it says that Sauron had "redone" the trolls, so to speak. He had taught them not to be so witless, and had crafted them horrible weapons. Hence, a more menacing enemy. <P>Plus, as stated in Sam's song, trolls' hides are difficult to pierce. <P>Didn't anyone think Legolas looked a little jerky when he was on the troll, by the way? I mean, I don't have a visual recording of the LAST time I saw an elf jump on a cave troll ( ) but it still looked kind of strange.