Nightly News | February 09, 2014
>> back here in sochi tonight. this year's olympics, just like back at home in the nfl, more than ever we're hearing more and more talk of the danger and prevention of head injuries . at the women's slopestyle snowboarding finals a 23-year-old czech athlete came down so hard after a fall that it cracked her helmet open. she is said to be okay. it's more reminder of the danger faced by athletes. more tonight from kevin tibbles.
>> banged up my shoulders. got a lot of concussions.
>> few concussions here.
>> hit my head a few times on the ice.
>> and gave myself a pretty bad concussion.
>> reporter: often just beneath the surface.
>> oh, no!
>> reporter: a hidden and dangerous adversary. kaitlyn cahow was at the top of her game and then came the hit.
>> i got crushed, blind side hit and didn't see it coming. that was it.
>> reporter: a law school student she found she could no longer read, concentrate or even form sentences, forced to take a year after school.
>> i was a 26-year-old person with a harvard degree in law school , two-time olympian and i couldn't do basic functions.
>> reporter: kevin pierce was a half-pipe favorite for vancouver when he fell from the sky.
>> my life was so certain. i with his a snowboarder and i was going to snowboard.
>> reporter: now he only boards for fun. competition, too dangerous.
>> this was the wake-up call for me.
>> reporter: these days he can be found raising awareness, helping others, helping himself.
>> still kind of talking about what i've had to come through and what i've had to overcome. it's been a huge for me.
>> reporter: ath lees of any sport are at risk, even this javelin thrower who tripped and fell in a wind-up during practice. his team is constantly looking for troubling signs. most athletes who experience concussions don't lose consciousness.
>> concussions can lead, potentially, to long-term deficit later in life. we need to be vigilant as health care providers that we watch each person as an individual.
>> reporter: the danger of concussion changes with each new sport and new and more challenging maneuvers.
>> and there it is!
>> reporter: after extensive rehab, kaitlyn cahow was clear to compete. instead she made the hardest decision in her life.
>> when you've become the best at something you want to keep winning. it's difficult to walk away from that sfwlr recognizing that one more hit could bring with it a life of repercussions, she made a tough decision to hang up the skates. kevin tibbles, nbc news, chicago.