EDINA, Minn. - The NFL reported 233 player concussions in 2016. That number is down from 2015 but still higher than previous years.

The league has implemented several rules aimed at protecting players.

This upcoming season, they'll go high-tech, testing equipment including a device designed by a Minnesota start-up company. The goal is to get real-time alerts of possible concussion-causing hits.

Athletes in collision sports like football and hockey take hard hits to the head. But despite everything we now know about concussions, no one agrees just how hard of a hit it takes to cause one.

“Nobody on the planet knows,” said researcher Adam Bartsch from the Cleveland Clinic.

Bartsch hopes to find the answer thanks to his high-tech mouth guard.

“So we'll know how many hits are too many, how hard can someone get hit in the head and be OK, and how hard someone can get hit in the head and not be OK,” Bartsch said.

Bartsch is the co-inventor of Prevent Biometrics' head impact monitor. The Twin Cities-based company is nearly ready for teams to start using the product to alert coaches, trainers or parents when an athlete is hit hard enough to cause a concussion.

Inside the mouth guard is a sophisticated microcomputer including accelerometers to measure the impacts. But it's still flexible and not much thicker than an average mouth guard.

“It just really takes a lot of worry out of it for the coaches and the parents,” said Prevent Biometrics CEO Steve Washburn.

Prevent Biometrics tested out the product last season with the Wayzata football team.

Washburn says if a player is hit is hard enough a red light stays on, so coaches know the player needs to be looked at.

Then, for each player wearing a mouth guard, an iPad app tracks the force of every hit.

“Then we also measure the location of the impact and the direction the impact came from,” Washburn said.

The company hopes local schools and youth teams will be able to buy the mouth guard this fall or early next year.