My arm is slightly bent, but it is also extended all the way out. Here is what I mean by that.

I hold the bow with my thumb and forefinger. So my hand is sort of turned 45 degrees to the grip anyway. I roll my left shoulder (I am right handed) back and down (low bow shoulder). That naturally rotates my elbow straight away from my body. So my elbow is fully extended, but, my arm still has a slight bend. This way, I have NEVER hit my forearm, but I am relying on bones, not muscles, for my support, which I think is a much more repeatable and solid platform for accuracy.