ACL Injury Prevention

What is the ACL? 

The Anterior Cruciate Ligament is an important stabilizer of the knee. It sits inside the knee joint in between the femur (thigh bone) and the tibia (shin bone). The ACL is the primary stabilizing ligament in the knee preventing excessive movement of the femur on the tibia. The ACL also acts as a sensory structure detecting changes in the knee's position, speed, acceleration and direction of movement as well as force acceptance during cutting, pivoting, jumping and landing. It is commonly injured in sports that include cutting, pivoting and jumping such as Soccer, Basketball or Volleyball. It is particularly susceptible to injury during periods of deceleration associated with sport such as landing from a jump or slowing down to perform a cut or pivot. For youth athletes, it is especially important to maintain integrity of the ACL due to the demands of sport, for proper development and to protect other important force accepting and stabilizing structures of the knee. 

Why are Young Female Athletes at Greater Risk? 

ACL injuries are an unfortunate reality of youth athletics with youth female athletes at the highest risk. Female soccer players are up to 8x more likely to experience ACL tears compared to their male counterparts. Youth female athletes find themselves at higher risk for a multitude of reasons including anatomical and developmental differences, neuromuscular control differences and differences in training. 

Simply, youth female athletes tend to have smaller, thinner ligaments on average. This is especially true during and after puberty when different hormones will affect ligaments to make them looser. Concurrently, during growth spurts, strength often lags behind natural, rapid limb length at this point in development. In turn, this results in a decrease to surrounding muscles' ability to stabilize the knee joint as effectively. 

Youth female athletes also experience differences in neuromuscular control of their bodies. Movement studies will show that many young female athletes will rely on their stronger quadriceps muscles during periods of deceleration rather than their weaker hamstrings resulting in larger shearing loads placed on the knee joint, ACL included. EMG studies will also show delayed muscle activity for female athletes in stabilizing muscle groups like glutes and hamstrings during periods of deceleration. These factors are modifiable with proper training of listed stabilizing muscle groups in order to reduce excessive forces on the ACL. 

Lastly, youth female athletes are less likely to be exposed to specific strength and agility training in conjunction with their sport of choice. This is something we hope to help change. 

How do I Prevent ACL Injuries? 

A lot of factors that contribute to ACL injuries can be influenced with a proper training regimen. An efficient training program that includes 20 minutes of exercises 2-3x/week can reduce the risk of ACL injury by up to 70%. Strength training to address muscles that aid in stabilization of the knee are paramount to a comprehensive sport-specific training program. Muscles that aid in stabilizing the knee during deceleration include hamstrings, calves and glute muscles. Incidentally, having a strong core and stable trunk is also a key factor in maintaining balance during athletics. As mentioned before, the ACL also has a function in proprioception and balance of the knee. Subsequently, training single leg balance and activities that include reaching outside of an athlete's base can prepare young athletes for the variable conditions that are inherent to participation in sports. 

What the Program Includes:  

• Neuromuscular Training: bolster coordination, balance and control 

• Strength Training: focus on muscles that stabilize the knee (core, hip, quadriceps and hamstrings) 

• Landing & Cutting Mechanics: improve movement patterns during periods of deceleration 

• Athlete & Parent Education: teach the tenets of an effective, efficient prevention program 

Helpful Resources: 

FIFA 11+ Warm-Up Program: fifa.com/fifa11plus 

PEP Program Information: smsmf.org/smsf-programs/pep-program 

Training Gym & Physical Therapy Clinic: Teamworks Sports Performance & Five Star Physical Therapy, Acton MA