I played 10 years of football, was struck in the head thousands of times. 我曾打过十年橄榄球，数千次被球打中脑袋，

And I have to tell you, though, what was much worse than that was a pair of bike accidents I had where I suffered concussions,  但我可以告诉你，自行车事故中我遭受的脑震荡要更为严重，

and I'm still dealing with the effects of the most recent one today as I stand in front of you. 现如今当我站在你面前时，我还在从最近的那次脑震荡中恢复

There is a fear around concussion that does have some evidence behind it. 对脑震荡的恐惧，有些是有道理的，

There is information that a repeated history of concussion can lead to early dementia, 有证据表明，反复多次脑震荡，会导致早期痴呆，

such as Alzheimer's, and chronic traumatic encephalopathy. 比如阿耳茨海默氏病，也会导致慢性的创伤性脑病，

That was the subject of the Will Smith movie "Concussion." 这是威尔·史密斯主演的电影《震荡效应》的主题，

And so everybody is caught up in football and what they see in the military, 几乎每个人在橄榄球比赛中，或是在部队里，都会遭受脑震荡，

but you may not know that bike riding is the leading cause of concussion for kids, sports-related concussion, that is. 但你可能不知道，对孩子们而言，骑自行车才是脑震荡的主要成因，即运动相关脑震荡，

And so another thing that I should tell you that you may not know is that 我还想告诉在座各位一件事，你们或许也不知道，

the helmets that are worn in bicycling and football and many activities, 诸如自行车和橄榄球等运动，所规定佩戴的头盔，

they're not designed or tested for how well they can protect your children against concussion. 并不是为了防止或减轻脑震荡而设计的，

They're in fact designed and tested for their ability to protect against skull fracture. 事实上，此类头盔的目的在于保护头骨，预防头骨骨折。