On a chilly mid-September evening, hundreds of fans filled the East Ridge High School football stadium in Woodbury to cheer for their team. The hum of the crowd reached a fever pitch as cheerleaders chanted for star players in rhythm with the marching band's drums.

The opening kick-off between the Raptors and the Mahtomedi Zephyrs brought the crowd to its feet.

It's a seasonal Minnesota ritual many decades old. But for the 25,000-plus high school students playing football this year, for their coaches on the sidelines and for their parents in the stands, the game is different from what it was even a few years ago. The reason? Concern over head injuries.

Hundreds of players have been pulled from games and practices, game rules have changed and parents have been involved more fully in what their teenage players are experiencing, a months-long MPR News and KARE 11 reporting project found. Using the state data practices law, the project queried more than 100 districts about their policies, their budgets and other matters related to high school football. It found rapid change in recent years but it also made clear some schools have taken more steps than others.

• In the three years since a state law required players suspected of suffering head injuries to be pulled from games and not allowed to return without medical clearance, schools have complied hundreds of times. But the law doesn't require schools to keep track of those injuries. Some do and some don't.

• Most schools survey football players' cognitive abilities before the season by conducting baseline tests to compare memory, reaction time, speed and concentration before and after injury. Some schools don't.

• Virtually all schools provide parents with detailed information about safety and head injuries. Some schools do more than others.

• The rules of the game have changed, allowing referees, for example, to impose greater penalties to punish behavior on the field known to lead to injury.

• Some schools have changed the way they hold practices, reducing the amount of contact between players, and coaches are finding ways to teach students to play differently. Next year, the Minnesota State High School League will require all schools to adopt some practice changes.

• Schools are using better equipment, although the amount of money spent on helmets in particular varies, as do policies about using reconditioned helmets.

Those findings are based on responses and follow up interviews involving 103 of Minnesota's 333 school districts. Those districts include 139 high schools.

To be sure, medical experts point out injury can't be eliminated in a sport that is inherently violent. Football participation in high school remains high, and many parents and coaches say the benefits of the work ethic and camaraderie players learn outweigh the risks, pointing out that student athletes can be injured playing any sport.

How schools respond to head injury concerns

Click on each district surveyed by MPR News and KARE 11 for information about its football program. For some districts with multiple high schools, click on the pin representing a school.

Source: MPR News / KARE 11

3-year old law raised awareness

The fact that more players are being pulled out mid-game or during practice indicates both a greater awareness of the short and long-term risks associated with concussions and compliance with a Minnesota law passed in 2011. The law requires a coach or official to remove an athlete from play or practice when the athlete is suspected of suffering a concussion or is exhibiting signs, symptoms or behaviors consistent with a concussion.

Video: Ben Utecht started playing football when he was just a kid and made it all the way to the Super Bowl. He suffered a career-ending concussion and now speaks nationally about the risks of head injury and football.

A student cannot return to play until all symptoms are gone and he or she receives written permission from a qualified medical provider. All 50 states have passed similar laws on concussions in sports for youth and high school players, according to the Centers for Disease Control. Read Minnesota's Return-to-play law.

"Since we've had the return-to-play law, we've seen an explosion in people paying attention to concussions and we're seeing more kids come in to make sure that their brains are working appropriately," said Dr. Mark Gormley, a Pediatric Rehabilitation Specialist at Gillette Children's Specialty Healthcare in St. Paul.

"I think that concussion management in high school in Minnesota has changed quite considerably over the past few years. I think it's gotten a lot better and I think mainly it's education and awareness," Gormley said. "I think people are aware that when you have a concussion you are damaging the brain, and if you do that repetitively over a period of time you can cause permanent brain damage."

Gormley, a youth concussion expert who examined the information school districts provided to MPR News, concluded that most schools are complying with the law.

But their responses show that school districts are complying in different ways.

Dr. Ron Tarrel, a neurologist with Noran Neurological Clinic in Minneapolis, also analyzed responses to the survey and recommended that districts follow more uniform practices. Tarrel noted that districts had different protocols for tracking injuries, for information parents and athletes get about risk and for equipment monitoring procedures.

Ben George, 14, of Ramsey Minn. George was diagnosed with a concussion after receiving hits in football and falling on the ice during hockey practice. Courtesy of Sports Star Photography

"It's not about pointing fingers," Tarrel said. "It's not about finding faults. It's about accumulating data to continue to refine and put together the best law that gives you the best awareness, the best preventions, the best treatment, best outcome for their athletes."

Like many Minnesota student athletes, Ben George of Ramsey, 14, is a two-sport kid. He plays football and hockey at the youth league level. But last fall, after receiving several hard football hits, then falling even harder on the ice during hockey practice, Ben had to stop playing - at least temporarily. After complaining of severe headaches, Ben was diagnosed with a concussion.

Video: What is a concussion?

"My theory was that the two hits in football are what made him vulnerable to the fall when he was in hockey," Ben's mother Bridget George said.

Before Ben could return to play, he went through a structured rest and recovery process through Gillette. The program included brain exercises and cognitive testing. Since a concussion is not visible in the brain with modern medical technology, cognitive testing is the only way doctors can determine if the brain is healed.

What does a student have to do to play again? Gillette Children's stages for returning to action. Gillette Children's

"The first part of the process is resting the brain just like any other injury," Gormley explained. "Once they are no longer having symptoms, we take them through a staged process of increasing their activity progressively until they can tolerate that activity and then we let them return to play."

Ben eventually got better and seven months after his injury he was cleared to return to the game, but he will take part in only one sport when he attends Anoka High School next year.

"He made a choice between football and hockey, and he's going with football," Ben's mother said. "I still have anxiety about it because it feels like once you have one, you're vulnerable and maybe you stay that way. But I have to be confident that between some of that guidance and Ben's own ability to monitor his symptoms, that we have a good plan."

Video: Logan Hauser also played high school football. His position was left tackle for Saint Thomas Academy. After several debilitating concussions he had to quit the team.

Earlier this month, the Minnesota Department of Health released its first compilation of injuries reported under the new law, an estimated 3,000 concussions among high school athletes in all sports. More than 40 percent involved football players, partly because more kids play football than other sports. The numbers were based on school districts that tracked and reported numbers to the state.

• Related: Teen athlete concussion estimates jump

Those numbers are in line with what districts told MPR News. The 130-plus high schools that responded reported more than 1,800 football players were removed from practice or a game since the law was enacted. In very few cases did a player return to the same game, but many returned days or weeks later after receiving the required medical clearance.

Anoka-Hennepin, Minnesota's largest school district, reported the highest number of players removed. Since 2011, 133 football players in the district's five high schools were removed because of concerns about concussions. Not one returned to play in the same game.

In those same three years, South Washington County's three high schools reported 126 players removed. Osseo's three high schools reported 80 players removed. Eastview High School in the Rosemount-Apple Valley-Eagan School district reported 79 players taken out of the game because of concern about concussions.

Several sizable school districts outside the Twin Cities reported similar actions. Rochester reported 79 players removed at its three high schools since 2011. Mankato's two high schools reported 68 players removed, and 62 players were taken out of practice or play in New Prague.

But not all schools have pulled players off the field. The Mountain Iron-Buhl school district, with 24 varsity players on the roster, reported no football-related concussions since 2011. South St. Paul also reported no players pulled from the game because of concern about concussions, and the New Ulm school district said the number of players removed from the game during that same time period due to concern about concussions was "unknown."

"We really limit the contact we have during the week," Mountain Iron-Buhl head coach Dan Zubich said. "All of our hitting is done Friday nights. We have been very lucky with head injuries. We watch the heads up concussion video the first day of practice and really stress the importance of shoulder down, head up tackling."

While the numbers at some schools may seem high, concussion experts say that may be a function of closer monitoring as opposed to more kids getting hurt.

Running back James King, Jr., 34, is tackled as he scores a touchdown for DeLaSalle against Edina. Tom Baker / For MPR News

"If athletes and parents and coaches and healthcare providers and administrators are aware of the problem, they understand the symptoms and signs, they're able to recognize them and maybe they're compelled to refer to a healthcare provider because of the law, then we are seeing more folks, which is a good thing," said Dr. Michael Stuart, an orthopedic surgeon and sports medicine expert at Mayo Clinic.

About a fifth of the high schools that responded to the MPR News survey said they don't track concussions among football players. That includes the schools in Minneapolis, the state's third largest district. One district, Faribault, responded by saying, "We don't write a policy for everything...we just try to do what's right."

Keeping track of that information is something medical professionals say is one of the most important things a school district can do because it can help identify trends and lead to safety improvement.

"I think someone needs to put together a uniform checklist, if that's what it is, that every school can use," said Tarrel. "People will know better what they're looking for and better know how to respond to it."

"It doesn't take much to track," Gormley said. "You can have your school manager track - how many kids had concussion symptoms, how many of them were resolved, when did they resolve."

More info for parents and for doctors

Minnesota's new law doesn't require schools to report injuries to the state, but the Department of Health would like to expand its voluntary approach to get more experience collecting and interpreting the data.

The law does require school officials to provide information to athletes and parents about the risks of concussions. While the information and number of documents varied, all of the school districts that responded to the MPR News survey said they provide some type of concussion information to student athletes and their parents.

Document: Eden Prairie football players must acknowledge the potential for brain injury.

Some districts, including Centennial, Bemidji and Eden Prairie, even host mandatory safety and information meetings before the season begins.

In some districts doctors are getting more information, too, because of testing schools encourage. Because a concussion is not visible through any kind of brain scan, the only tool doctors have to determine whether an athlete has been injured and then healed is a test of cognitive abilities.

A baseline cognitive measurement assesses an athlete's balance and brain function, learning and memory skills, ability to pay attention or concentrate and how quickly he or she thinks and solve problems. The athlete answers a series of questions, usually on a computer, and the results can be compared to a similar exam later if an athlete has a suspected concussion.

Most Minnesota school districts that responded to the MPR News survey offer baseline tests to football players before the season begins. But 17 districts reported they do not offer those tests, including big districts like Minneapolis, Eden Prairie and Roseville.

Changing the rules

Concern about head injuries has also affected the rules of the game itself and the way coaches conduct practices.

"We feel that football now is safer than it's ever been," said Kevin Merkle, associate director of the Minnesota State High School League, which governs interscholastic play across the state.

The kickoff run-up has been shortened to five yards to slow the play down and make impacts between players less forceful. For all kickoffs, including onside kicks, at least four players are now required to stand on either side of the kicker to balance the formation.

And when it comes to penalties, Merkle said the terms 'targeting' and 'targeting a defenseless player' have now been defined in the rulebook, and officials are being told to enforce targeting penalties more than they have in the past. Targeting a defenseless player used to be called 'unnecessary roughness.'

Video: Minnesota State High School League Assistant Director Kevin Merkle describes how the league is trying to decrease the amount of head injuries

"If kids are kicked out of the game because they launch and lead with their head, they can't play the next game and that sends a strong message," Merkle said.

The league hasn't tracked how often those penalties are called, but Merkle said it may survey schools at the end of this season.

The league is also moving to reduce contact in practices. Starting next year, the league will limit to six the number of practices coaches can have in June and July in which players make contact with each other. Limiting contact means less opportunity for hits to the head.

The league is also looking at limiting the number of total practices in the summer and limiting the amount of contact during contact practices, Merkle said. The next step, he said, is changing practice guidelines for the August pre-season and the regular season as well.

Many states have gone a step further and passed laws that limit contact during football practice. In California, one of the most recent states to pass such a law, the measure limits practices with full-on tackling during the playing season and prohibits them during most of the off-season.

Merkle said most Minnesota football programs have already limited hits in practice on their own.

This is important because the rate of concussions is higher during practices than during games, said Dr. Grant Morrison, a physician at Fairview Sports Medicine in Eden Prairie. "If there were fewer contact-related practices, the sheer reduction in the number of possible injuries, it's got to reduce the rate of concussions," Morrison said.

Play low, keep heads up

Several districts say they've changed the way they practice. Calling safety his top priority, Stillwater head coach Beau LaBore said his teaching, coaching and practice techniques aim at keeping injuries down.

LaBore and coaches at other districts said they are teaching players to keep their heads up, to play low and to always have their feet underneath them, techniques known to lead to less violent contact during play. LaBore said his players are not allowed to use their helmets as weapons.

Video: Good tackling vs bad tackling

"It's a good thing that we have improved the way we coach the game, the way that we equip our players to play the game and ultimately ensure that the proper techniques and skills are being used to keep football as safe as it can be," LaBore said.

• Listen: How schools, doctors manage football risks. Aug. 26, 2014

Eagan High School head coach Rick Sutton told MPR News' The Daily Circuit program in August, "It's extremely important that we as coaches do a great job of teaching proper technique, that we make sure that our players are keeping their head out of the game."

Mayo Clinic's Stuart offered advice to parents. "Make sure that your child is learning the rules of the game, make sure that their behavior on the field is safe and that they're using proper blocking and tackling techniques, that they strengthen their neck muscles and use the entire approach for safety," Stuart said.

The role equipment does and doesn't play

On a fall afternoon in 1974 Craig Stroup, now 56 and living in Golden Valley, would play his first and last high school football game. He was 16, playing defense for Hopkins High School. Stroup tackled an opponent, a hit he would remember 40 years later.

"The left side of my head hit his knee," Stroup said.

He made his way to the sideline and collapsed, remaining in a coma for six weeks with a brain hemorrhage.

Stroup sued a football helmet company, claiming the helmet he wore should have absorbed the impact, according to Steve Stroup, Craig's brother.

But the injury was life changing. Craig Stroup will always need assistance and has virtually no short-term memory.

Craig Stroup sits in a patio area at his Golden Valley, Minn. home. Jeffrey Thompson / MPR News

"I totally understand football and why kids enjoy doing it, but (a head injury) really can change things, the whole dynamics of the family, and it can affect you for a lifetime," Steve Stroup said.

Helmet designs have changed significantly since Stroup was injured.

They are key to preventing skull fractures, but the scientific community has debated whether they can prevent concussions as well.

The National Operating Committee on Standards for Sports Athletic Equipment (NOCSAE) sets standards for all kinds of athletic equipment. At the high school level in Minnesota, if a football helmet doesn't have the NOCSAE stamp of approval it doesn't get used. NOCSAE is currently working on a new helmet standard that measures some of the forces known to lead to concussion.

NOCSAE's Executive Director Mike Oliver said equipment has come a long way in keeping players safer on the field.

"The technology has changed," Oliver said. "Some of the material science has changed. You can make shells thinner, but just as strong. There are variable density foams now that you didn't have back in the day."

Most experts agree that keeping football helmets in good condition, reconditioning them every year and making sure they fit properly, is very important. Reconditioning includes the inspection, cleaning, sanitizing and repair or restoration of the helmet to make sure it performs as it did when it was new.

Twenty school districts that responded to the MPR News survey have an actual policy to recondition helmets. Another 58 school districts said they have a procedure to evaluate the condition of helmets at the end of each season. Some recondition every year, others do it every few years. Most work with their individual helmet vendors to inspect and recondition.

In addition, all school districts that responded told MPR News that they purchase new helmets which are, in general, replaced every 10 years.

Some districts use football helmets rated highest by a controversial Virginia Tech star rating system that suggests a reduction in the risk of concussion based on the model of helmet a player chooses. But most experts say helmets can't reduce the risk or prevent concussions at all. They say helmets can protect the skull, but there is little - at least today - that can be done to keep the brain from hitting the inside of the skull, which results in concussions.

While equipment is important, it may not be the most important.

"It really starts with research to understand who's at risk, how concussions occur and then we take that information and look into strategies for prevention," Mayo Clinic's Stuart said. "The important thing is to make sure that we have the athlete's best interest in mind... focus more on conditioning, speed, agility, skill development...Will there be concussions? Of course. But this is not about elimination. This is about reduction of risk."

Read more

See documents here that show how schools, doctors and the state high school league have increased awareness about football head injuries.

Related KARE 11 and MPR News coverage:

• High school helmets tested for concussion risk

• Find your school's football helmet ratings.

• How much can helmets help?

Credits:

Reporter: Trisha Volpe

Visual reporters: Jeff Thompson, Jennifer Simonson, KARE photojournalists

Data analysts: Manda Lillie, Cody Nelson, Rachel Johnston

Web producer: Will Lager

Editors: Laura McCallum, Dave Peters, Regina McCombs