This past fall there was a lot in the news about head injuries and football helmets, and the opinion of some neurologists is that while helmets might protect against skull fractures, they do not do a good job of protecting the brain from rattling around inside the skull and being bruised. From what I understand about Schumaker is that his helmet split, but his skull was not fractured. Still he had a number of hematomas. I'm not sure bicycle helmets are good at protecting from that type of injury.