Youth involved in sports face a "culture of resistance" when it comes to reporting possible concussions and complying with treatment plans, researchers say.

Carried out by the Institute of Medicine and National Research Council, the report warns that the phenomenon could endanger the athletes' health.

Included in the study were a wide range of sports with athletes ranging in age from 5 to 21.

Overall, concussion rates were higher among high school athletes than college athletes in sports like football, men's lacrosse, soccer and baseball. The rates were also higher in competitions than practice, with the exception of cheerleading, and highest in football, ice hockey, lacrosse, wrestling, soccer and women's basketball. Finally, concussion rates also appear higher for youth with a history of concussions and among female athletes.

The researchers uncovered little evidence that sports helmets reduce the risk of concussions, but stressed that they -- along with face masks and mouth guards -- should be used to reduce the risk of other injuries, including skull fractures and bleeding inside the skull, among others.

In reviewing past studies and reports on concussion recognition, diagnosis and management, the team found that most young athletes recover from a concussion within two weeks, though in 10 to 20 percent of cases, the symptoms persist for weeks, months and even years.

In the case of a possibly concussive injury, athletes should be removed from play and only returned when he or she no longer exhibits symptoms. Those who return before their brain has fully healed place themselves at increased risk for prolonged recovery and more serious consequences should they experience a second brain injury, the researchers warn.

Overall, research regarding youth concussions is limited, and should be expanded upon in the following ways: establishing a national surveillance system to precisely determine the number of sports-related concussions, identify changes in the brain after concussions in youth, conduct studies to to asses the effects of concussions over a lifespan and evaluate the effectiveness of sports rules in reducing concussions.

"The findings of our report justify the concerns about sports concussions in young people," said Robert Graham, chair of the committee and director of the national program office for Aligning Forces for Quality at George Washington University, Washington, DC. "However, there are numerous areas in which we need more and better data. Until we have that information, we urge parents, schools, athletic departments, and the public to examine carefully what we do know, as with any decision regarding risk, so they can make more informed decisions about young athletes playing sports."