ACL injuries continue to proliferate among female athletes.  I am passionate about preventing them, and part of my professional mission is to study and evolve in my rehab and prevention training approaches all the time to stay on top.  I wanted to pass along some new information on a new screening tool just unveiled in the Strength and Conditioning Journal this month.

Before I reveal the screening and training tool, I want to take a moment and review what Timothy Hewett refers to as modifiable risk factors that contribute to injury risk based on his work:

  1. Ligament Dominance – defined as an imbalance b/w neuromuscular and ligamentous control  of dynamic knee stability and it is visualized by loss of frontal plane control with landing and cutting
  2. Quadriceps Dominance – defined as an imbalance between quad and hamstring strength, recruitment and coordination
  3. Leg Dominance – defined as an imbalance between the two legs with respect to strength, coordination and control
  4. Trunk Dominance ‘Core’ Dysfunction – defined as an imbalance b/w the inertial demands on the trunk and its ability to resist or control/resist it

Previously, Hewett has identified that high knee abduction moments are related to high LOAD on the knee and a major risk factor for ACL injury.  He and his colleagues have done extensive motion analysis in their lab in Cincinnati, OH.  As such, a drop landing test has been used as one tool to observe landing mechanics and assign some risk value to athletes competing in cutting and jumping sports.

In the current article (click here for the abstract) Meyer, Brent, Ford and Hewett unveil a new screening tool involving the tuck jump.  They propose that this tool is easier for the S & C coaches to do on the field and not only assess risk factors by way of observing technical flaws, but also use the tool as a training maneuver.

The idea is the subject will perform tuck jumps for 10 seconds consecutively while the observer makes notes on the following pre, mid and post jumping:

  1. Lower extremity valgus at landing
  2. Thighs do not reach parallel (peak height of jump)
  3. Thighs not equal side-to-side (during flight)
  4. Foot placement not shoulder width apart
  5. Foot placement not parallel (front to back)
  6. Foot contact timing not equal
  7. Excessive landing contact noise
  8. Pause b/w jumps
  9. Technique declines prior to 10 seconds
  10. Does not land in same footprint (excessive in flight motion)

Factors 1-3 refer to knee and thigh motion, 4-7 refer to foot position during landing and 8-10 refer to plyometric technique.  Coaches are instructed to grade the flaws if seen with check marks during the phases they are seen and use this as a guide for correction.  They may also use cameras in the frontal and sagittal plane to assist them.

My thoughts on this are:

  • There is sound science behind the rationale for the test and modifiable risk factors
  • There is a need for basic no-cost screening tools coaches can apply in their settings
  • The tuck jump assessment will provide instant feedback on form and identify technical flaws that may indicate higher risk for injury
  • The tuck jump is a higher demand plyo drill so I fear poor form may be as much to blame on inexperience and unrefined motor patterns as it is to just dominance patterns so we need to keep plyo training experience in mind when analyzing the screen results especially for beginners
  • The tuck jump assessment does not really consider fundamental movement restrictions that may bias the form on one side if an asymmetry is present
  • I still wonder how much ankle pronation impacts landing and whether we will see more research on this – there was a study done at ECU where they used orthotics and saw a reduction in ACL tears in their collegiate athletes so I have to wonder about this crucial element of the kinetic chain

In the end, we still lack many answers.  According to data published in the Journal of Athletic Training in 2006, non targeted neuromuscular training programs need to be applied to 89 female athletes to prevent 1 ACL tear.  So, we need to keep studying and applying science to our training, all the while critically questioning science and looking at our athletes holistically to find the best prevention strategies for each one individually and for at risk athletes as a whole.