There are a couple of things to take away from that story. First off, harnesses, helmets and Racing seats do wonders. The ability to firmly plant you ass in the seat and keep it there during high G impacts should not be underestimated.
Secondly, even with all that restraining equipment, your noodle still managed to find the bar. Your soft tissues and neck in particular can stretch and contort in amazing ways in a high G impact. Hence the need for a good full face helmet.
You neck is holding up a 10 lb bowling ball plus a helmet. In a collission G forces can exceed 100Gs making your head the equivalent of 1000lbs.. Protect the noodle out there boys.