Now that football season is finished, a prime storyline going forward is player safety, particularly in regard to concussions. The NFL doesn't hold a monopoly on that topic, though. It ranges from the highest level of sports to the youngest players, covering activities on a variety of athletic fields.

The discussion also is present in doctors' offices and research labs, courtrooms, legislative offices and even in movie studios.

In the military, concussions have been diagnosed in more than 300,000 service members since 2000 — the most common injury among military members in that time.

The concussion timeline is difficult to trace. Research and medicine regarding head injuries advance so quickly that it's difficult to anticipate where it will lead. We do know this: Concussions are serious injuries that no longer can be addressed with the old-school "shake it off" mentality. The phrase "concussion protocol" is now as much a part of watching football games as are commercial breaks. The injuries hold long-term repercussions.

Concussions and their aftermath have led to lawsuits by NFL and NHL veterans, attracting further public attention. Both sports have seen suicides related to head trauma. The NFL's recent Hall of Fame induction included former quarterback Ken Stabler, days after it was disclosed that he had suffered the brain disease chronic traumatic encephalopathy (CTE), which is tied to brain injuries.

A recent study by Canadian researchers revealed that individuals who have suffered concussions are three times more likely to commit suicide, listing the number at 31 per 100,000 people annually. The link between concussions and suicide is notable, particularly for the military. The Pentagon reported that active-duty suicides among service members rose in 2014, when the most recent statistics are available, and the Veterans Affairs Department declared decreasing suicide among veterans is a top priority.

With the injuries giving them common ground, sports and military officials are teaming up to change culture regarding head injuries through the Mind Matters Challenge. The $4 million program launched in 2014 offers grants for scientific research into affecting healthy behavior toward concussions. It falls under the NCAA-Department of Defense Grand Alliance, which puts $30 million toward changing the culture in sports and the military.

While football and the military draw most of the focus, concussions are widespread in other activities, some of which do not require helmets or other head protection. The injuries occur in soccer, among both males and females, not only from heading the ball but from contact between players and head impact from falls.

In ice hockey, concussions have ended pro careers or have haunted players through their playing days. Among youth hockey players, researchers recently stated that illegal hits are the cause of more than 40 percent of that sport's concussions. Young hockey players also take longer to recover than more mature skaters, according to the study.

Athletes in baseball, softball, lacrosse, basketball and martial arts also suffer from concussions, and the BMX world couldn't avoid the discussion after a top rider, Dave Mirra, committed suicide earlier this month. Legislatures across the country have considered measures related to the head injuries, including in Maryland, where a proposal would suspend high school coaches who keep concussed athletes in games.

Back to football, a survey by the Public Religion Research Institute shows that increasingly parents are opposed to allowing their children to play. Participation in the national youth football program Pop Warner football fell nearly 10 percent between 2010-12, ESPN reported.

The issue has reached a point at which it has spawned extensive research. It's also given birth to an industry that is manufacturing and promoting wide-ranging solutions that include new helmet designs and on-site blood tests. The question is whether we will be able to reach a solution before much more damage is incurred.

In Part 2, a look at some of the solutions to concussions.