Q: A girl on my daughter's soccer team tore a ligament in her knee, called the ACL. Is there a way to prevent this injury in soccer?
A: Soccer is a great team sport that has grown in popularity in Canada over the past 20 years. It is also a sport with a lot of running and quick turns. Unfortunately, as in all sports, injuries do happen in soccer and they do not always occur with contact from another player. Soccer has the dubious distinction of being one of the sports that has a high rate of anterior cruciate ligament (ACL) knee injury.
The ACL is the most important ligament in the knee. It is attached from the thigh bone to the leg bone in the knee joint. It prevents our knee from sliding too far forward and from turning too far. The ACL tear injury is a permanent injury. This means that the ligament does not repair or heal. A complete tear to the ACL ligament in the knee results in instability or the feeling that the knee is loose, especially with turns and pivoting movements.
Traditional treatments for the torn ACL include bracing for turning sports and reconstruction surgery. The reconstruction surgery takes a piece of the kneecap tendon (patellar tendon) to form a new ligament. It takes many months before a sport like soccer can be resumed after surgery. So far, followup studies in those who chose brace or surgery are showing that a large number of patients are developing osteoarthritis in the injured knee. Thus, an ACL tear in the knee has long-term consequences because once osteoarthritis does form, there is no known way to reverse this process.
Females are two to four times more likely to tear their ACL than males. It is estimated that ACL injuries account for about five per cent of all soccer injuries in females. Since, females account for almost 50 per cent of the all soccer players in many parts of Canada, there are a lot of ACL injuries every soccer season. The ACL injury is more likely to occur with cutting, pivoting, running and landing from jumps. A collision with another player is not usually involved.
Sport scientists are looking at why females are more vulnerable to the ACL injury. There are many possible factors such as hormonal change in the first half of the menstrual cycle, increased flexibility of hamstring muscles, increased laxity of the knee joint and neuromuscular problems. The latter has been the focus of training programs to try to improve the reaction time of muscles to protect the knee. Drills that teach players to land with their hips and knees in a more bent position are becoming more popular. A knee over toe position when cutting is also helpful.
There are other sports that have high female participation and involve a lot of quick turns, pivoting and landing from jumps. One of these is ballet and it is gathering a lot of attention from sport scientists because ACL injuries in ballet are rare.
This presents the question, why are females in soccer more vulnerable to ACL injury than females in ballet? Preliminary studies have revealed that an athlete's position sense (proprioception) may be more fine tuned in ballet dancers. Position sense refers to the ability to know where one's arms and legs are positioned without looking at the arms and legs. Ballet dancers are trained extensively in being aware of their arm and leg positions. When compared to soccer players, ballet dancers can reproduce bent knee positions more accurately without looking at the knees and legs.
Thus, females may be able to gain better position sense with ballet training. Although, soccer and ballet may seem like sports with very different movements, the ability to protect one's body from injury is a common link to all sports. Perhaps, a little bit of ballet will go a long way on the soccer field.
Dr. Maureen Kennedy MD, CCFP, FCFP, MSc, PhD(c) Kinesiology, Dip. Sport Med., is a sport and exercise medicine physician at Sport for Life Centre, www.sportmedicinecentre.ca
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