I came across this article in Slate today regarding American Football and a new category of head injury that has been discovered.

To sum up: It begins with the mention of G as the force of gravity, and the fact that in collisions, force is measured in G's. It seems that collisions in this heavy contact sport range from 40Gs at the low end to 300Gs at the more brutal extreme. Guys getting wrecked with forces of this magnitude naturally leads to a high number of concussions to compliment the myriad other corporeal injuries.

Until now, head injury was thought to be diagnosable on the field by physicians. The classic symptoms of concussion are quite easily recognized.

The feature of the article, however, is new research which suggests that there are other very alarming kinds of head trauma, the signs of which are not easily recognized. It mentions blows to the top of the head, and subsequent impairment of the 'executive functioning' of the brain.

Naturally, my thoughts strayed to last night's practice, and to kendo in general. We hit each other - right on the top of the head no less - many many times per practice. We have bogu of course, just as American Footballers have helmets, and a shinai is perhaps a far cry from the impact of an airborne man, but I can't help but wonder just how much damage we may be incurring, and at what cost later on down the line.

Does anyone know of any studies in English regarding the amount of force in Gs that a normal men-strike generates?

Further still - regular strikes aside, how many times have you really had your bell rung in kendo, been caught off guard or broken your posture and really got cranked?

p.s. - [it has come to my attention that I threw this one up absent a tune at the end. That means a few people have missed out on this collymellon Billy Holiday/Lester Young track. Apologies! 07/03/2011]