17 mayo 2015 año - Chris Borland retires
Descripción:
49ers linebacker Chris Borland retires from football, becoming the first player to walk away in his prime out of fear of long-term brain damage.
Añadido al timeline:
How football has gotten where they are with concussions
A look at the history of how the phenomena of concussions gr...
fecha:
Fotos:
![]()
