STANFORD, CALIF. – Help girls avoid the sports injuries that are more common for them than for boys by clearly explaining energy requirements, recommending prevention training programs, and educating about concussions.
Brains and knees face extra risk from sports injuries in girls than in boys, and only girls develop the Female Athlete Triad – disordered eating, amenorrhea and osteoporosis.
In gender-compatible sports such as soccer or basketball, girls have higher concussion rates than do boys and more postconcussion symptoms. Anterior cruciate ligament (ACL) injuries are two to eight times more common in females than in males. Approximately 1% of female high school athletes meet all three criteria of the Female Athlete Triad, 6% may meet two criteria, and approximately one in five may meet one of the criteria, Dr. Jennifer L. Carlson said at a pediatric update sponsored by Stanford University.
• Female athlete triad. The key to prevention is education. Dr. Carlson explains to patients that they should consume 2,200-2,400 kcal/day (depending on their age) if they are "active," meaning their daily activity is the equivalent of walking more than 3 miles/day at 3-4 mph. If they do more, they’re "very active" and need 2,500-4,000 kcal/day, depending on the sport and the number of hours spent training.
"Many have no idea that that’s what they need to be taking in," said Dr. Carlson of the university.
Girls also need to hear that losing one’s period is not a sign of fitness. And coaches may need to be asked to de-emphasize weight goals and abandon harmful weight-loss practices.
"I’ve had athletes in non–weight-class sports where the coach monitors weight" and even asks them to get a bone density scan, for no good reason, Dr. Carlson said.
One study of 170 female athletes in six Southern California high schools found that 1% met the three criteria for female athlete triad and 6% met two criteria. "But any one of the three criteria is pretty significant," Dr. Carlson said, and 18%-24% in the study had one of the individual criteria (Arch. Pediatr. Adolesc. Med. 2006;160:137-42).
The three criteria of disordered eating, amenorrhea, and osteoporosis that were identified in 1992 have evolved, and today would be described as low energy availability, menstrual disturbances, and low bone mineral density, she said. These can lead to fatigue, difficulty concentrating, emotional lability, impaired athletic performance, stress reactions, and fractures.
The triad is most likely in sports such as gymnastics in which the athlete is scored partly on aesthetics, endurance sports such as cross-country running that favor low body weight for better performance, sports like wrestling or crew that have different weight classes, or any sport in which clothing reveals body contours.
Physicians can find helpful resources about the syndrome from the Female Athlete Triad Coalition website, she said.
• ACL injuries. In females, ACL injuries most commonly come from noncontact maneuvers in sports involving sudden stopping and changing of direction, known as "cutting." The injuries range from small, mild tears to completely torn ligaments. Prevention focuses on awareness of risk factors and specific training programs.
Prevention training programs focus on minimizing risky positions (such as landing from a jump in an upright position instead of crouched), increasing balance and knee stiffness, and decreasing ACL strain. Training programs significantly reduced the risk for ACL injuries by 60% in a meta-analysis of six studies (Am. J. Sports Med. 2006;34:490-8).
The elite and collegiate-level sports programs incorporate prevention training programs. More and more experts advocate for them to be integrated into sports programs for prepubertal age groups, she said.
Greater friction on playing fields increases the risk of ACL injury. Generally, artificial turf is thought to be riskier, and wet surfaces may decrease risk of an ACL tear. Females may have higher risk because of neuromuscular or anatomic factors (such as wider hips) or less core stability, some think.
Biomechanical differences contribute to risk, compared with males. Hormones play a role, too. The peak time of female ACL injury is in the first phase of the menstrual cycle, and oral contraceptives seem to be protective, probably because of the action on neuromuscular junctions that hormones affect, Dr. Carlson said.
• Concussion. Higher rates of concussions in girls playing gender-comparable sports may be caused by reporting bias if boys are more reluctant than girls to report the injury, some speculate. In a recent study of 296 athletes, however, females had worse visual memory scores and more concussion symptoms than did males after a concussion, and neurocognitive impairments persisted as long as 10-21 days for high schoolers and 5-7 days for college athletes (Am. J. Sports Med. 2012;40:1303-12).