More than 40 years ago, National Football League Hall-of-Famer and Kansas City Chiefs linebacker Willie Lanier took a hit that changed everything.

More than 40 years ago, National Football League Hall-of-Famer and Kansas City Chiefs linebacker Willie Lanier took a hit that changed everything. He knew after hitting the knee of a San Diego Chargers player during a 1970 game that he had suffered a concussion. But he didn’t pay attention to the effects until about a week later, when he collapsed on the field calling a defensive play and was unconscious for two hours. From extra padding in his helmet to a new defensive style emphasizing bear hugs instead of head-first charging, Lanier said he realized that day the effects — the potentially fatal effects — that a serious hit to the head can have. “It completely changed the way I played the game,” he said. Years later and half a world away, Fort Leavenworth Command Sgt. Maj. Christopher Greca was close enough to a 2010 explosion in Kabul, Afghanistan, that he suffered some easily identifiable external wounds, though those aren’t what concern him now. “The effects weren’t the stitches that I had. It wasn’t the external wounds. It was potentially the long-lasting effects,” he said, of the trauma to his head. From the practice field to the battlefield, the NFL and the U.S. Army are joined at the head, so to speak, on the issue of traumatic brain injuries. In August, leaders in the two organizations, Army Chief of Staff Gen. Ray Odierno and NFL Commissioner Roger Goodell, signed a memorandum of understanding to share knowledge and discuss on an ongoing basis traumatic brain injuries and ways to protect those in both military and football uniforms from their long-term effects. Representatives from both the Kansas City Chiefs and Fort Leavenworth discussed those ongoing efforts and their own experiences with TBIs and what they called a change in culture surrounding such injuries during a forum Wednesday on post. Lt. Gen. David Perkins, commanding general of Fort Leavenworth, said one need not look back far to see the evidence of how brain injuries were treated in the past. In combat and in contact sports alike, he said those who may have suffered a concussion were often given smelling salts and told to get back out on the field. “These things would happen over and over again, because we didn’t know what we didn’t know, just like in football,” he said, “and that’s what we are seeing the results of today.” According to Col. Emery Fehl, commander of the Medical Department Activity and Munson Army Health Center at Fort Leavenworth, more than 253,000 cases of traumatic brain injuries among all Department of Defense service members have been diagnosed since 2000. Of those, he said 84 percent of the incidents happened outside of a deployment. Being on the front lines of the culture change surrounding TBIs gives the NFL and the Army both an incentive to work on better ways to diagnose and to make strides toward better treatment for the injuries as well as a position of authority when it comes to those changes. Mark Donovan, the Chiefs president who was also part of the panel, said he feels the players need to lead as individuals and the larger organizations need to lead as a whole to create top-down change. Rule changes in regards to tackling in the NFL enacted in 2010 were not immediately embraced and were in fact criticized, Donovan said. But, two years removed, he said those policies are starting to trickle down to college, high school and little league levels. “What we do is mimicked,” Donovan said. Criteria for when a player can return to the field after a head injury is also constantly evolving, he said, with an independent neurologist now required to sign off before a player can return to action. Fehl said the Army, too, has been updating protocol for those who have suffered concussions in the field. Under the current guidelines, he said those who might have suffered a TBI are taken out of battle for at least 24 hours. Testing is also getting better, Greca said, with MRIs in theater in Afghanistan and baseline testing providing a standard by which to more precisely diagnose head injuries after a deployment. They have to lead, panelists said, because to some extent it is the values that command so much respect for both organizations — the so-called “warrior mentality” that pushes them to persevere through injuries — that has worked against them in the past. Danan Hughes, a former Chiefs wide receiver who spoke at the forum, said after one particularly hard hit at the end of his career he lost consciousness and all feeling in his body. But his first reaction was not of his own health. “When I awoke two seconds later, my first thought as how am I going to finish the game and how can I fool these doctors so I can?” he said. Lanier said he is able to boast of the decisions he made in 1970, having none of the artificial knees or hips common to NFL retirees and no signs of dementia. He said those outcomes are not out of reach for more athletes and soldiers alike. “I know that if instructed properly, individuals will see an opportunity to be better, to perform well, to truly grasp that which gives them the opportunity to say what I’m saying later on and not unfortunately have their futures robbed from them,” he said.