Dave Lang was warming up for the Aggressive Inline League championship in 2014.

He was attempting a 900 degree spin over a launch box at Woodward West, a trick he’d done numerous times before and numerous times after.

This time, however, he overshot the landing, and landed on a flat surface. He hit his head but didn’t lose consciousness.

Lang, a 27-year-old professional rollerblader living in Hollywood, was cleared by on-staff medics and ended up winning the competition later in the day.

The next day, he felt nauseous and called an ambulance.

At the emergency room, a CT scan showed he had an acute subdural hematoma.

“Despite its name, it’s no small injury. It is when bleeding fills the brain. I actually get sick thinking about it,” Lang told Healthline. “I wasn't wearing a helmet. Doctors said if I had been, it probably wouldn't have been as severe. Now I'm full-time helmet because my risk is much greater for a reoccurrence than if I were to ignore it. I've been wearing one since my injury.”

He was airlifted to a Bakersfield hospital where he was sedated but felt everything that was happening to him. In his 15 years of skating, it was the hardest he’s ever hit his head.

“Fortunately, I haven't noticed any personality changes, which is common amongst traumatic brain injury survivors and I am thankful for that,” he said.

Read More: Get the Facts on Concussions »

More Than Just NFL Players

Those personality changes Lang refers to are often what people notice after a major head trauma or after years of less severe ones.

Traumatic brain injury (TBI) has been making headlines — and there is even a movie about it starring Will Smith — after former players in the National Football League (NFL) began experiencing depression and symptoms similar to Alzheimer’s disease earlier than normal.

Chronic traumatic encephalopathy (CTE) is a condition that can result after repeated TBIs. It is a concern for athletes, soldiers who’ve seen combat, and others repeatedly exposed to concussions.

CTE, which can only be diagnosed after death, is believed to be the result of the jarring nature of concussions and other TBIs.

While helmets can protect the skull from impact injuries, the brain is still jostled, opening up the opportunity for tau protein deposits.

Researchers with the Department of Veterans Affairs and Boston University say CTE affects about 80 percent of all football players.

But it doesn’t just affect people who play mainstream sports like football, hockey, and soccer, who are at risk of long-term brain injury.

Read More: Are High School and Youth Football Too Risky for Kids? »

Action Sports Stars at Risk

In May, BMX legend Dave Mirra was posthumously diagnosed with CTE, making him the first action sport star to be diagnosed with the condition.

The revelation opened up the public discussion regarding the risks associated with contact sports, especially where the contact is between the athlete and the concrete.

Mirra sustained numerous head injuries during his career on a bike and then started boxing after his retirement. He died from a self-inflicted gunshot wound to the head on Feb. 4. He was 41 years old.

The Centers for Disease Control and Prevention (CDC) estimate between 1.6 million and 3.8 million sports-related concussions occur in the United States each year.

The National Ski Areas Association reports that the number of skiers and snowboarders who incur TBIs that are serious enough to see a doctor increased 106 percent from 2004 and 2010, according to Outside Magazine.

As action sports continue to gain mainstream acceptance, more cities are constructing skate parks, offering relatively safer spaces for various wheeled sports enthusiasts to do their respective activities.

Concrete Disciples, an online database of skate parks, lists more than 3,100 skate parks in the United States alone. While many have signs requiring helmets and pads, few — especially those operated by municipalities — have the resources to enforce such rules.

Overall, helmet rules — unless at a staffed skate park — are often self-enforced. In the action sports community, those rules are often shunned, along with other forms of padding.

There’s limited data available regarding the rate of TBIs in action sports. There’s no central governing body for action sports, unlike the NFL and other professional sports organizations, to track injury data.

What are available are anecdotes and clips from competitions and skate videos.

Read More: Super Bowl QB Troy Aikman on Melanoma, Concussions »

Concussions Vastly Underreported

This week, a report from the Children’s Hospital of Philadelphia and the CDC states that rates of concussions and brain injury in children are probably vastly underreported.

This is due, in part, because concussion diagnoses are primarily symptom-based and data is collected often only by emergency department visits.

Their research found that 82 percent of children were diagnosed with a concussion through their primary care doctor, compared to the 12 percent admitted to the emergency department. A third of those concussions were diagnosed in children under age 12.

Children in their tween and teen years are the primary demographic for action sports like skateboarding, so the risk for TBIs is continually there.

But much like traditional sports athletes who for years were told to merely to walk it off and get back into the game, action sports athletes often want to get back up right away to try the trick again until they get it right.

And there aren’t any coaches or staff to make the call for someone to sit the rest of the day on the metaphorical bench.

That’s part of the allure of action sports. Yes, there’s danger, but there’s also the satisfaction of pushing oneself outside their boundaries to accomplish what no one else has before.

Lang knows the feeling well, as he’s known in his sport for always going bigger and faster than last time.

“I think it's about doing what you know best and pushing it when you are truly feeling it,” he said. “There is inherent risk that is involved. It’s important to use your best judgment and focus in order to surpass your limitations. Sometimes you get the horns, but that's a risk we all take in loving what we do.”

Still, he’s gained a lot of perspective from his injury, including skating with a helmet. He calls it “a huge wake-up call and changed my viewpoint on life entirely.”

“What I have noticed is my willingness to put myself out of my comfort zone in my career outside of skating, which, by some sort of divine intervention, began after I had made a full recovery,” he said. “I am very fortunate to be here after said injury. And coming back is very intimidating. But, you need to relocate that ‘on/off switch’ that brings you to a place where you are just skating and nothing else exists.”