Raised arm block in real life

Spent the weekend clearing fence lines of trees. There's still so much more of it to do. Unfortunately, found myself underneath a Willow as it was being felled. Fortunately, it wasn't one of the huge ones. It was only about 4 inches (10 cm) in diameter. That forearm came up just in time to protect my head. Instinct or Kung Fu? Not sure, but I'm glad it's my arm that hurts and not my head.

I think I still need to work more on that last second rotation a bit more though.