It's still a matter of debate, though, whether the ordinary knocks involved in "heading" the soccer ball raise the risk of brain injury.

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Unfortunetly, a teammate of mine got knocked in the head last night by a shot on goal from really close range. The guy shot it as hard as he could and Pete took it square in the face. He took himself off the field and another teammate (who is an ER doc) checked him out. He had significant vision loss (couldn't make out number of fingers) and blood in the anterior chamber of his eye that made his iris red and raised his ocular pressure. His vision was still blurry today but he should be ok.