A torn anterior cruciate ligament could bench any of the girls for six months — or permanently.

The 36 varsity and junior varsity girls laughed at their odd-looking movements and cheered each other on as trainers corrected their movements. They're among the 1,200 female athletes at 24 high schools in Monroe County, N.Y., learning how to prevent noncontact ACL tears.

"Soft landing!" called Missy Wilson, one of two University of Rochester (N.Y.) Medical Center's University Sports Medicine trainers running the program. "Bend your knee more!"

Female athletes are at much greater risk of ACL injury than male athletes. Among suspected reasons are that girls and women tend to remain more upright while playing sports, putting more strain across the knee when they stop, start or land, said Dr. Michael Maloney, chief of University Sports Medicine.

Experts also suggest that female athletes' bodies are structurally different and that hormone changes could play a role.

More than 1.4 million women have had ACL tears in the past 10 years nationally, twice the rate of the previous decade, said Andy Duncan, physical therapist and director of sports rehabilitation at University Sports Medicine. An estimated 30,000 or more high school and college-age females suffer the injury each year.

The anterior cruciate ligament is one of four main ligaments connecting the thigh and shinbones. The ACL is in the middle of the knee and stabilizes the joint by preventing the shinbone from sliding forward in front of the thighbone. A partly torn ACL may heal on its own or may require surgery. A fully torn ACL won't heal by itself.

ACL injuries most often happen when the foot is planted on the ground while the leg is being twisted, a common occurrence in football, soccer, basketball and skiing. ACL injury can also occur when the knee is overly straightened (hyper-extended), during a sudden stop while running or during a sudden transfer of weight.

Shauna Dean, a senior at Olympia High School in Greece, N.Y., has experienced three partial or full ACL tears to her right knee. She's had six surgeries to fix the ACL and to repair cartilage. The first injury happened the summer before her freshman year, during a basketball tournament.

"I went to make a cut and it went 'pop,"' she said.

After each surgery, she had to recover and rebuild. She had to skip sports in ninth grade, but in 10th grade made the varsity soccer team, a sport she'd played since childhood. But after the latest ACL tear in 11th grade, combined with other health issues, Shauna's no longer playing contact sports.

"It's definitely been probably the greatest challenge I've been through," the 17-year-old said. "Having to start over every time takes its toll."

Maureen Randall, 15, a JV co-captain at Sutherland High, said the agility moves make her muscles sore, as the trainers warned. But, she said, "I think every team should do this."

Bonnie DeVinney of the Greater Rochester Health Foundation said it awarded the $101,295 grant to fund the program because it has great promise.

The Prevent injury, Enhance Performance, or PEP, program reduced noncontact ACL tears by up to 88 percent in a two-year study of 1,400 NCAA Division I female soccer players by Santa Monica Orthopaedic and Sports Medicine Research Foundation.

"It's a proven training program," said DeVinney, foundation vice president and chief program officer.

Each ACL injury can cost $17,000 in surgical repair and rehabilitation, not counting possible future complications, such as osteoarthritis or total knee arthroplasty, which are believed to occur more often in ACL-deficient or ACL-reconstructed knees. On top of that is the emotional and psychological cost.

Helen Zickl, a seventh-grade gymnast and diver from Batavia, N.Y., tore her ACL four years ago — when she was only 8 years old. Doctors were surprised to find it was an ACL tear for such a young athlete, said her mother, Rachel Zickl.

"Rehab was very difficult," Helen said. "It was so hard trying to get my leg used to all the activity again. But after five months of rehab I went back to the gym and after about a month I got back into (real practice)."

Shauna Dean, who is still captain of the varsity soccer team, said her teammates daily do the new moves that they learned from the University Sports Medicine trainers.