I like how the prevalence of the position of linemen is included later, but for clarity and to limit the amount of bias before introducing a key fact like prevalence on the field after prevalence within the disease, it's imperative to restructure here.

While 1300 players have died since the recent inception of the Brain Bank, how many more players have played the game and not had symptoms? Is there something more at play?

The study specifically regards linemen and defensive backs as being the two primary groups, but running backs are not considered as heavily in the original paper due to the limited frequency of consecutive repetitive impacts.