Concussions are common among girls who play soccer in middle school, according to a new study reported by HealthDay reported.

According to the Centers for Disease Control and Prevention (CDC), there are about 173,286 sports-and-recreation-related concussions among children and adolescents up to 19 years old in the United States every year. Researchers at the University of Washington School of Public Health in Seattle found that 50,000 of those concussions are linked to high school soccer players.

"While high school athletes are represented in the concussion literature, youth players traditionally lack injury tracking systems and are largely unstudied, which is concerning since younger age and female sex are risk factors for sports-related concussion," according to the study authors.

Since little research has been done on middle school athletes, especially girls, researchers set out to determine the incidence rate, frequency and duration of concussion symptoms among female youth soccer players. A concussion is defined as a traumatic injury to the brain after a blow, shaking or spinning

For the study, researchers evaluated 351 soccer players between the ages of 11 and 14. They found 59 concussions in the group examined. In the study, the girls' symptoms included headache, dizziness, drowsiness and concentration problems.

Melissa Schiff, co-author and a professor of epidemiology at the University of Washington, told HealthDay that the rate of injuries among middle school girls is higher than what has been reported at either high school or college level women's soccer.

Thirty percent of the injuries were caused by "heading" the ball, an action that involves the player hitting the ball with her forehead to redirect the ball. More than half of the concussions were from contact with another player.

Researchers also found that the majority of soccer players continue to play even when they have concussion symptoms, increasing the risk of a second traumatic injury, HealthDay reported.

Experts recommend those who have a concussion be evaluated by a doctor or other health care professional trained in the injury, but researchers found that 56 percent of the soccer players in the evaluated group were never evaluated.

The study was published online on Jan. 20 in the journal JAMA Pediatrics.