I specifically paid attention to whether I'd get hung up in brush while using the extenders at (max) height and I didn't really ever get hung up, even going through thick mesquite groves at the edge of washes while coues deer hunting. (Some of that stuff you have to crawl through.) There were a few times I'd have some small branches caught between my shoulders and pack bag, but I've had this happen before using the frame extension(s) too. It seemed like the extended frame moved with your body and if your head fits, the frame extender will fit. I could see more of an issue if the extension was closer to the outside of your shoulders, but with it being just outside the neck/head area it wasn't a big deal. Hope that makes sense.