Girl athletes are eight times as likely to injure their knee’s anterior cruciate ligament, or ACL, than their male counterparts, finds a U.S. study.

“With more girls competing in soccer, basketball, gymnastics and volleyball — sports requiring maneuvers such as jumping and landing, or quick stops and turns — more cases of ACL injuries are being seen,” says Dr. Christopher S. Ahmad, director of the Center for Pediatric and Adolescent Sports Medicine at Morgan Stanley Children’s Hospital and of the Columbia University College of Physicians and Surgeons.

The study, of 53 female and 70 male recreational soccer players ages 10 to 18, suggests that adolescent girls tend to develop increased quadriceps strength, while not increasing hamstring strength. With very strong quads overpowering the hamstrings, an imbalance occurs, leading to undue stress on the ACL, according to the study published in the American Journal of Sports Medicine.

The researchers also suggest that girls become skeletally mature earlier during puberty, and they tend to perform their sports activities in a more upright position that adds stress to the ACL.