"The important thing is, there's a big difference between the bad and the good," he said. "There's a big difference between a 1-star helmet and a 4-star. There's not so much difference between a 4-star and 5-star."
Analyzing nine years of data from Virginia Tech, in which players wore helmets equipped with sensors, Duma's team found an 85 percent reduced risk of concussion in a 4-star helmet vs. a 1-star helmet.
Brooks' study will factor helmet ratings in in the next year of research, which involves 1,332 players from 36 high schools, she said. Brooks also found that brands of mouth guards probably aren't important in terms of reducing concussion risk: Players who were generic, school-issued mouth guards actually had fewer concussions than those who wore specialized mouth guards.
Helmets alone won't solve the concussion problem. That's partly because of the nature of the brain's anatomy.
"The anatomy of the brain floating freely inside the skull and the subsequent mechanism of injury will make it difficult to significantly reduce concussion risk using helmet technology alone," Brooks said. "I think focus could be better spent on rule enforcement and coaching education on tackling technique to limit/avoid contact to the head, perhaps limiting contact practices, and behavior change about the intent of tackling to injure or ‘punish' the opponent.'"