There used to be a time when athletes would get knocked in the head, fall to the ground, struggle to get back on their feet and wobble around before regaining their bearings.
It used to be called "getting a ding." Athletes were encouraged to just "walk it off."
That still happens in many sports, from the youth levels all the way to the pros. But over the past few years, recreational leagues, schools and athletic associations have gotten more serious about these head injuries.