Extreme sport athletes say they're becoming more aware of traumatic brain injuries like CTE.

(AP Photo/David Zalubowski)

Dave Mirra, one of the biggest stars in extreme sports, committed suicide in February. Months later, an examination confirmed that Mirra, a BMX rider, had the degenerative brain injury called chronic traumatic encephalopathy, or CTE. The diagnosis evoked thoughts of well-known National Football League players like Hall of Fame member Junior Seau, who also suffered from the disease.

But it also moved the conversation on head trauma to amateur athletes and to recreational activities like biking and skiing that are part of the fabric of Colorado. Dan Koeppel, a California-based journalist, recently wrote a piece for Outside Magazine which said head injuries are increasing across the country. A 2015 study analyzed more than 4 million emergency room visits in the U.S. from 2000-2011, and was published last year in the Orthopaedic Journal of Sports Medicine. It reported a steadily rising number of concussion injuries in seven sports: surfing, mountain biking, motocross, skateboarding, snowboarding, snowmobiling and skiing. Snowboarding was the most concussive activity, with 42,811 concussions over that 10-year period.

Koeppel spoke with Colorado Matters Host Ryan Warner.

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Why Colorado Is At The Forefront Of Extreme Sports Medicine