Knee ACL and Lower Extremity Injuries: Can we prevent them in our young athletes? Part II

By Dr. John R. Mishock, PT, DPT, DC

In my last article, (Knee ACL and Lower Extremity Injuries: Can we prevent them in our youth athletes? Part I) determined that lower extremity injuries make up 66% of all sports injuries, with the knee being the most commonly injured joint.(Med Sci Sports Exerc. 2002) These injuries lead to a significant cost in; financial (cost of the surgery and rehab), lost playing time (9-12 months), lost ability in return to play (63% return at pre-injury status), the potential for re-injury (25% re-injury), and long term increased risk of osteoarthritis of the knee (4 times greater risk). Thus, there is a great need to prevent ACL and lower extremity injuries. The goal of this writing is to highlight the research based prevention techniques in order to make the consumer more educated on what you should look for when seeking a training program.

The internet is filled with unscrupulous trainers who try to sell programs that promise improved sports performance and injury prevention. Many of these trainers have little or no experience in human anatomy, muscle and body physiology, sports biomechanics, and the science of enhancing sports performance and injury prevention. From a research perspective, here are the key components that must be included in any sports performance and or injury prevention program for the lower extremity.

  1. Due to the fact that most knee ACL and lower extremity injuries are non-contact (70-80%) in sports such as basketball, soccer, volleyball, lacrosse, handball, and football the biomechanics and neuromuscular dysfunction must be addressed and modified. Improper landing leads to a 4.6 times great risk of an ACL injury. (Am J Sports Med. 2005). Proper biomechanics in movement starts with the ability to land after jumping along with proper angles in cutting, pivoting, and pushing off while running. The ability to control the body in a variety of movements (sagittal-plane, frontal- and transverse-plane motion) decreases knee-joint loads helping to prevent injury.
  2. From a neuromuscular perspective, training should start with core/trunk stability and strength. The core/trunk is “slang” term which includes the muscles of the back, hips, and abdominals. A strong stable core provides the base of support from which all extremity movement. Because the hips (hip abductors and external rotators) indirectly control the valgus of the knee, strength and motor control training of these muscles can significantly reduce the risk of lower extremity injury.
  3. Decreased hamstring strength or the imbalance between the hamstrings and quadriceps muscle groups may place individuals at an increased risk for ACL and lower extremity injury (Knee Surg Sports Traumatol Arthrosc. 2015, Clin J Sports Med, 2009) Strength and power training of the hips, thighs and lower leg along with motor control training will help prevent lower extremity injury.
  4. Decreased flexibility of the lower extremity (iliotibial band, hamstrings, and piriformis muscles) increases the chances of ACL and lower extremity injury (J Sports Med Phys Fitness. 2007).
  5. Poor single-legged balance indicates impaired neuromuscular control and is a risk factor for lower extremity injury (Sports Health. 2013). Balance exercises often involve single-legged– or double-legged–stance tasks that incorporate various levels of visual input (eyes open → eyes closed), surface stability or hardness (stable → unstable and hard → unstable and soft), and external perturbations (no perturbation → moving extremities → catching a ball → partner perturbation).
  6. Plyometric training incorporates explosive movements, such as repeated jumping or bounding. Agility training addresses several important motor skills (e.g., acceleration, deceleration, accurate changes of direction within the environment).
  7. The program should be performed during the preseason and in-season at least 2 to 3 times per week. Some teams have been able to implement a program as part of a dynamic warm up to start practice or training.
  8. The coach or trainer should be skilled in identifying faulty movement patterns to ensure excellent movement quality and provide feedback on exercise technique.
  9. If time constraints are a concern, some evidence indicates that multicomponent training programs can be performed in 10 to 15 minutes as part of a dynamic warm-up before the start of practices and games.

With proper training, athletes can expect up to a 52% to 62% reduction in ACL injuries when commencing an ACL injury prevention program. (J Bone Joint Surg. Am. 2012) Bottom line, a complete program should have; strength, plyometric, agility, balance, and flexibility training along with emphasis on the biomechanics of landing. A strong program highlighting these areas will not only help in injury prevention but will also enhance sports performance.

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