Cheerleaders often have to defend themselves against critics — some don’t consider cheerleading a “real sport,” and they’re often dismissed as athletes. The stats are in their favor, however, backing up the physical difficulty of cheerleading as a sport, and a dangerous one. A new study suggests that injuries that occur among high school cheerleaders tend to be more severe than those of other athletes, Live Science reports.

The research showed that of the 22 high school sports studied, 17 of them had higher injury rates than cheerleading. However, cheerleading ranked second, behind gymnastics, among sports ranked for the proportion of injuries that caused athletes to be benched for at least three weeks.

“Although overall injury rates are relatively low, cheerleading injuries may be more severe when they do occur,” the researchers, from the Colorado School of Public Health and the University of Colorado, wrote in the study.

The team completed the study by analyzing data gathered from between 2009-2014 through a national high school sports injury surveillance system. They found that concussions were the most common injuries from cheerleading, making up 31 percent of the injuries. 70 percent of the concussions occurred during stunts (when cheerleaders lift teammates into the air), whereas 16 percent occurred during pyramid formations and 9 percent occurred during tumbling.

Most of the concussions that occurred during stunts were caused by contact with another person, for example, getting elbowed by someone. During tumbling, most concussions resulted from hitting the head on the floor, according to the researchers.

Of all the cheerleading injuries, around 34 percent allowed cheerleaders to return to their sport in less than a week, and another 41 percent allowed them to return between one and three weeks. Eleven percent, however, sidelined cheerleaders for three weeks or more, and 5 percent ended their season or career. Concussions were again the most common injury to result in a time loss of three weeks or more.

The researchers recommended that evidence-based efforts to prevent injuries in cheerleaders be aimed at specific activities that put cheerleaders at risk for the most severe injuries.