At Greenback High School in eastern Tennessee, senior Jordan Anderson has taken his share of hard hits on the football field.

"I actually have had a couple of times where I thought, you know, this might be a concussion,” he said in a TODAY segment that aired Wednesday. “But nothing major. It's all been just minor incidents."

Football season has begun this year amid a striking estimate from the NFL: Nearly 3 in 10 retired players will develop debilitating brain conditions like Alzheimer's disease or dementia. The concern of the long-term effects of traumatic brain injury has reached the high school and pee wee levels, where young players are especially vulnerable.

Some youth leagues and high schools, including Jordan’s, are trying to stay a step ahead of debilitating injury, using new impact sensors that tell coaches when a player has taken a potentially serious hit.

While Jordan has never suffered a concussion, many young athletes around the country have. The concussion rate for high school athletes in the United States has more than doubled since 2005.

This season, Jordan’s coach at Greenback raised enough money from the community to buy six Riddell helmets equipped with the sensors.

"We have 37 football players right now,” Jason Hicks, the Greenback coach, told TODAY. “So out of those, about five or six have probably had concussions. “Research is beginning to show that once a kid is concussed, he's more susceptible to that brain trauma again,” he added. “Those were the kids that we want the sensors to be on."

While these sensors can’t prevent or diagnose a concussion, they send alerts to a handheld monitor when the helmet takes significant impact.

“So our trainers and our team doctor are being able to pull that kid off and quickly evaluate him,” Hicks said. “If he doesn't show symptoms of a concussion, then they can send him back out on the field."

Jordan’s sensor has recorded two significant hits, but he showed no signs of concussion and was cleared to return to the field.

“You really don't ever realize it until the trainer says, ‘You know, you had a significant hit,’ and then you kind of remember, ‘yeah, that was a hard hit,’” Jordan said.

Impact sensors are uncommon below the college level but many helmet manufacturers have begun marketing sensors for high school and pee-wee football players.

While school across the country have reported using the sensors, their use is still at the discretion of individual teams and parents.

The cost of the sensors varies. The Brain Sentry sensors cost about $75 each; the Riddell sensor costs about $150 per helmet and $200 for the monitoring system.