Why haven't football players benefitted more from these helmet sensors designed to detect dangerous hits to their heads?

This is Scientific American's 60-Second Science. I'm Benjamin Meyers. Got a minute?

According to Purdue's Eric Nauman, that is because for over a decade,

[Eric Nauman:] "People have been looking for the wrong…the wrong indicator. They were looking for the one type of hit that causes a concussion."

Several research groups use these sensors to track force, location, and number of hits.

Nauman and his colleagues Tom Talavage and Larry Leverenz at the Purdue Neurotrauma Group focus on what they consider to be the most reliable information: how many times a player gets hit.

The group found two things in high school football players. First, some brain damage happens without a concussion at all. Second, it's more about the number than the type of hit.

Players with more hits are more likely to show brain function changes by the middle of or after the season. These supposedly healthy players have changes as bad as concussed ones—or even worse. Fortunately, some athletes recover in a few months. But others don’t’.

That makes the timing of the study important. Studies that only look at players' brain function before and after the season might miss in-season injuries.

Their research shows that even without a concussion, brain damage can occur with repeated hits. And earlier than people might have thought.

The findings trigger new questions for athletes at all levels. The Purdue researchers are looking for how many hits are safe for different sports. They and other researchers are also trying out different scans to understand more about subconcussive injuries.

So, should football teams limit hits like baseball teams limit pitches?

[Nauman:] "I think without a doubt they should be limiting hits."

Thanks for the minute! For Scientific American's 60-Second Science, I'm Benjamin Meyers.