"A minor traumatic brain injury."
"Occurs when the head hits an object, or a moving object strikes the head. Can affect how the brain works for awhile."
Like when a soccer player heads a ball flying down the field. Or when a football player crashes into an opponent. Or when a rugby player slams the ground.
Given the possible consequences, it's worth it to sit on the sidelines for three weeks rather than have a damaged brain.
Concussions have risen to national and world recognition, from pro circuits to high school teams. In the last two years, concussions and their after-effects have been at the forefront of sports news, aided by the ongoing lawsuits of former NFL players.
Though it circulates as national news in the professional circuits, it also matters on a smaller scale - like in high schools, where students aren't likely to make millions as professional athletes. They will need their minds well into adulthood - and will likely be using their brains to make incisions as surgeons, to calculate equations on a building's structure, to measure out prescriptions and more.
Sports Illustrated recently ran a story about concussions and their aftermath - the aftermath that lasts a lifetime.
For Jim McMahon's girlfriend, Laurie Navon, it's recognizing and living with the symptoms of early onset dementia that's a part of life with her loved one. McMahon is just 46 and loses his bearings regularly, presumably the effect of four documented concussions and uncounted others.
According to SI, more than 140 lawsuits have been filed by players and their families against the NFL alleging the league concealed information about the dangers of repeated blows to the head.
Their arguments may have clout, but then again, the long-term effects of concussions may not yet be fully understood.
Most medically trained professionals know a bruised brain is a damaged brain - but to a large extent, they don't know how far that damage extends. What they do know is, it's important to let the brain heal.
Even Summit High School trainer Steve Sedlak, who is charged with recognizing the signs and symptoms of a concussion, says there's little pattern. A student could get a concussion from something as simple as tapping his head with a baseball bat in frustration or as clear as slamming into the turf.
Sedlak said the effects of such brain jostling - at any level - can range from slowed reaction time to short-term memory loss.
But how do they know there's damage in the first place? Baseline tests help.
Thanks to Avalanche Physical Therapy, all Summit High School fall athletes were given free baseline testing this year, an important tool to for coaches, trainers and physicians to gauge an athlete's return to sports. Previously, the school offered baseline tests for $10.
The 250 free baseline tests covered all fall athletes, and some tests remain for winter athletes who haven't been tested. The grant also provides two post-concussion check-ups for 75 students. So far this season, physicians have recommended three students take advantage of the more extensive testing.
Sedlak and physicians use the baseline tests to help ensure the athletes under their watch allow their brains to heal to the point of normalcy (to their baseline). The test measures reaction time and memory through shapes and numbers. Sedlak likes asking athletes to count backward from 100 by sevens to test their mental capacity after a hit to the head.
After being cleared, an athlete must go through a controlled program as he or she returns to play.
"It allows a safer return to play," Sedlak said. "You can't be too careful with a head injury."
Colorado's youth concussion law
Here again is a big question mark, because returning to play too soon can cause what's known as second-impact syndrome, where bleeding in the brain causes the body to shut down. The science makes sense, but the cause isn't clear even to many on the inside, Sedlak said.
"We don't know why it spontaneously happens after a second hit," he said.
Youth brains are still developing and can sometimes take longer to recover after injury, experts say. And it's estimated that 1,500 to 2,500 - a conservative estimate - youth athletes visit Colorado emergency rooms for sports-related concussions annually.
In 2004, concussions and their aftermath - particularly second-impact syndrome - became a widespread topic of conversation in Colorado, when Grandview High School's then-freshman Jake Snakenberg collapsed in the football huddle after taking a not-so-extraordinary hit and subsequently died.
A week earlier, Snakenberg had been hit during a game and noticed tingling in his fingers, but didn't let on to his father. The day before the game in which he collapsed, he'd had a helmet-to-helmet crash that also seemed to leave him unaffected.
That was in 2004, and in March 2011, awareness had spread to create the Jake Snakenberg Youth Sports Concussion Act, also known as Senate Bill 40.
It requires that all coaches and trainers of youth ages 11-18 complete annual concussion recognition education. The trainings are free, quick and available online. But it goes further. The law requires that a coach pull an athlete from play if he or she has sustained a concussion. That athlete must be evaluated by a licensed healthcare provider and cleared to return.