The tennis ball hit me on the forehead, while i was standing at the net. As far as i can remember, my head went back just about one inch(the ball weighs only 58 gramms).

I see how difficult it is to calculate the g's. But i think it is quite interessting to figure out how much is actually necessary to cause a concussion(for instance, everybody around me told me that a tennisball has not the enough force to cause TBI, but in fact it has)

When we say for instance that 10 g's are necessary, does this mean that the brain hits the skull only when a force of 10 g or more is reached or does it hit the skull also on lower g's, whithout resulting in a concussion? The question is interessting, because sneezing or twitching makes me feel dizzy for a while - is that because the brain touches the skull?

(Here is the link which i wanted to add in my last post www.braininjury.com/injured.shtml )