Slang: hench

Recently I've come across the current youth slang word 'hench'. It's an adjective meaning 'well-built' or 'muscular' (used to describe men only!). Sadly I haven't been able to find much about the origins of the word except for a few suggestions on the web that that it derives from "black English". Can anyone help here?

Much more rarely, I've also come across 'hench' used to mean 'mate', but I think this is a more recent development. A colleague suggested that 'hench' may be related to 'henchman', meaning "a faithful follower or political supporter, especially one prepared to engage in dishonest practices" (OED).

I'm not convinced by that argument - although it is interesting that 'henchman' is from Old English 'hengest', or male horse, plus 'man' (obviously), and may originally have meant 'horse attendant'.

If I were to choose someone to look after my horse, I'd probably pick someone who was a) well-built and b) a mate, so maybe there is a connection after all...