Audrey Tabon was playing in a 2001 summer basketball tournament before her junior year at Oakland Catholic High School when she jumped to catch a pass, landed off-balance and experienced "the worst pain I ever felt in my life."
She had torn the anterior cruciate ligament, or ACL, which connects the thigh bone to the shin bone, in her left knee.
Dr. Freddie Fu, head of UPMC's Sports Performance Center, operated, using part of her hamstring muscle to replace the ACL.
After a half-year of weight-lifting, balance and strengthening exercises, Tabon rejoined her team.
The comeback lasted five games. In March 2002, as Oakland Catholic played for the Class AAAA title in the Western Pennsylvania Interscholastic Athletic League, Tabon's repaired ACL tore.
She went up for a pass "and I did the same thing. ... That pain you recognize.
"[The rehabilitation] wasn't long enough. The graft was strong enough, but the muscles around the knee weren't ready," she said.
For the second operation, Fu used a tendon in her left knee to replace the torn ACL.
This time, Tabon, 18, of Point Breeze, underwent rehabilitation for nearly a year before returning to the team this past January. The knee held together as she helped her team go on to win the state championship in its class. She recently accepted a scholarship to play for Illinois next season.
Though she is not in UPMC's Female Athlete Injury Project that is exploring how to prevent ACL injuries in girls and women, Tabon demonstrated part of the theory that researchers hope to prove: that with the proper training and strengthening of involved muscles, the incidence of ACL injuries can be reduced.
High school and female college athletes, particularly those in basketball, soccer and volleyball, experience ACL injuries two to eight times more often than males. The injury occurs most often when an athlete is landing or cutting.
Differences in skeletal development and hormones are among the theories that may explain this phenomenon.
"We're interested in muscle function and how they influence staying out of vulnerable positions that lead to the injuries," said Scott Lephart, director of UPMC's Neuromuscular Research Lab who is overseeing the study. "We were looking for modifiable risk factors ... to decrease vulnerability.
"You can't change hormones, you can't change skeletal structure."
During Phase I of the study that began in 1995, Lephart and other researchers identified risk factors.
"Females still have reduced strength in their quadriceps [muscle in the front of the thigh] and hamstrings [muscle on the back of the thigh]," Lephart said. "They have a reduced awareness of body and joint position.
"When guys go up and down, they land and flex their knees and ankles more, which allows them to absorb the forces involved," Lephart said. "Girls are stiffer in the knees and ankles. The joints have to handle more pressure and that results in tears to ligaments."
Using those findings, the study team moved on to Phase II, during which they had teenage female athletes follow exercises designed to increase strength and improve balance (which enhances body perception) and agility.
The 25 girls who agreed to participate were split into two groups. One followed basic strength-training and stretching exercises.
"The other did more complex neuromuscular activities related to agility and cutting," he said. "These girls improved significantly more. They all got stronger, but in the second group they significantly improved their landing and cutting. That essentially was validation of our program."
The girls were taught to land and cut with their knee directly over their ankle and their hip directly over their knee instead of leading with their foot. That is the way boys and men position themselves, and it provides more stable support for the joints and lessens the pressure on ligaments and tendons.
Researchers are developing the study's third phase, where they will be looking at reduction of injury.
Lephart said a proposal for funding has been sent to the Department of Defense for Phase III. If it goes through, the intervention program would be implemented with a troop of 2,500 at one of the Army's basic training camps. Then the injury rates would be monitored over 12 months.
"Women in the military are getting the same injuries; they're landing, jumping cutting," Lephart said.
After this phase, the study will look at children to try to determine when gender-specific differences occur. This will help determine when physical education teachers and coaches might intervene in training to prevent future injuries.
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