Many people think of anything medieval in the modern world to be geeky and weird, such as the LARPing scene. While medieval combat may seem “uncool”, M-1 is pretty much like MMA in medieval gear with blunted weapons. The armor is quite heavy, often times weighing around 40-60 pounds of metal, and the swords itself are hard weapons despite the bluntness.
So despite all the protection, there is still going to be a significant amount of concussive force. The brain is the most vulnerable part of the human body, as brain injuries do not heal. Having a 6 pound chunk of metal swung at your head wearing a metal helmet is a recipe for concussion.