When more than 1.5 million youth football players across the country hit the gridiron this fall, a startling number of them will likely suffer a head-related injury.
Even though athletes may shrug off the discomfort of getting "dinged" or "getting your bell rung," these concussions can be quite serious.
A recent study found that 47 percent of high school pigskin players suffered a concussion each season, according to statistics gathered by the National Center for Injury Prevention.
Thirty-five percent of players say they had more than one concussion in the same season.
Multiple concussions increase the risk of long-term damage to the brain, doctors say.
Yet, most concussions at the high school level go unreported to athletic trainers.
Many young athletes and their parents don't know the telltale signs of a concussion. The symptoms include nausea, dizziness and headache.
To help students, parents and coaches better identify concussions and prevent them, the Centers for Disease Control and Prevention has published a free tool kit called "Heads Up: Concussions in High School Sports" that is available online at http://www.cdc.gov/ncipc/tbi/Coaches_Tool_Kit.htm
According to the American College of Sports Medicine, 300,000 sports- and recreation-related concussions are diagnosed nationwide each year.
However, the college estimates that 85 percent of concussions typically go undiagnosed.
Christopher Nowinski calls it a crisis.
The former Harvard football player and professional wrestler has written a new book entitled "Head Games: Football's Concussion Crisis" to bring attention to the issue that hits close to home.
Nowinski's career came to an end after he suffered a concussion while wrestling for World Wrestling Entertainment in 2003.
He later found out that he had sustained multiple concussions over his sports career, but did not know it.
"I wasn't getting very good answers from the experts to help me understand why I was suffering from headaches and memory problems and depression for weeks and even months after the impact," Nowinski said.
These injuries seem to be on the rise.
At Children's Hospital of Pittsburgh, football-related injuries have more than doubled over the last five years.
The hospital treated 92 football-related injury cases in 2005; most of them were head injuries.
Dr. P. David Adelson, director of the Pediatric Neurotrauma Center at the hospital, says concussions can be serious and can have a lifelong impact on young patients.
"It can have impact on their schooling, personality changes and behavior changes if the concussion is severe enough," Adelson said.
So what is a football-loving kid to do?
"It is crucial for young athletes to wear properly fitted helmets and other protective gear, and to learn proper tackling techniques."
In order to help alleviate head injuries, the National Collegiate Athletic Association and the National Federation of State High School Associations implemented rule changes in 1976 to prohibit using the head as the initial contact point when blocking and tackling.
Jeff Meyers, head football coach at Olathe East High School in Kansas, teaches his players to abide by that rule and says on average he sees fewer than one concussion a year.
"You never want your head down. We always try to keep face up," Meyers said. "We try to slide our head one way or the other when making contact."
Despite these cautions, many experts say that concussions are simply unavoidable in a contact sport, like football.
According to the American Association of Neurological Surgeons, a concussion is "an injury to the brain that results in temporary loss of normal brain function … usually caused by a blow to the head."
Adelson said, "A player who has sustained a concussion is more likely to sustain another."
It is those multiple concussions that worry author and former athlete Nowinski.
"Two concussions in a row is killing brain cells and even sometimes causing death," he said.
He noted that multiple head injuries had put an end to the careers of such NFL stars, like Troy Aikman and Steve Young.
"I don't believe there is necessarily a quick fix," Nowinski said.
He has ideas to curb the problem.
"Educate athletes and coaches about the injury. We also need to start getting more cases diagnosed and telling coaches, 'You can't let players get back on the field too early.'"