Young female athletes are more prone to injuries than their male counterparts and are injuring themselves at younger ages, in ways once seen only in advanced college and professional athletes.

Training — or rather, a lack of it — is among the primary reasons, according to researchers at The Orthopedic Specialty Hospital, who found in two studies an "alarming rate" of what is being called the female athlete triad: symptoms of disordered eating behaviors, irregular menstruation and injury.

Ranked marathon runner and sports dietitian Kristi Spence found that girls are not getting adequate nutrition to fuel themselves for sports. The interplay of poor nutrition or disordered eating patterns, irregular hormones and injuries is particularly troubling because teens and young women are still building the bone-mass foundation for their lives.

Worse, "it's not just athletic girls you have to worry about, it's girls in general," Spence said.

Girls are more apt to suffer chronic knee pain and stress fractures and are 1.5 times more prone to concussions in sports like basketball and soccer, which are popular with both genders, according to a recent article in the New York Times. Girls are up to five times more likely than boys to rupture ligaments in their knees.

Reasons include both physiology and differences in how genders prepare for sports. "There are certainly hormonal differences between boys and girls. Hormones make (females') joints more lax. They are not as strong as boys and not as fast. Obviously, these are blanket statements. There are some girls that can kick the holy you-know-what out of boys," said Jim Walker, sports science director at The Orthopedic Specialty Hospital.

But girls typically don't spend time in the weight room, and their sports are usually club sports, so they compete year-round, which means they hone skill rather than train. "That's where I feel the big deficit is. They're just not training," he said.

Girls often suffer non-contact injuries, get fatigued and can be hurt because they move the wrong way. "You rarely see that in football," said Walker. "They play for 10 weeks in the fall and spend the rest of the time training."

Spence said it doesn't require a "full-blown eating disorder to have a problem." Healthy eating has to leave a reserve of calories after an athletic endeavor, or the body thinks it's starving and starts shutting off "non-essential" activities, including production of metabolic and reproductive hormones. When that happens, the female athlete stops menstruating. But those hormones are essential for bone health.

Without periods, the young athletes may never reach peak bone mass, which typically occurs in a woman's late 20s. That leaves women more at risk for a variety of ills, including osteoporosis, stress fractures, arthritis, joint replacement and more.