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Brian Schiff’s Blog

Injury Prevention, Sports Rehab & Performance Training Expert

Tag: knee injuries

Whenever I speak at fitness industry events, I always tell my fellow fitness comrades that they must do everything in their power to elevate the profession.  I live in both the “rehab” and “training” world daily.  I can tell you unequivocally that the words “personal trainer” do not garner tons of respect in the medical community in many cases.

I will share a personal story from my professional work experience this week that illustrates why.  Yesterday, I evaluated a new patient (45 y/o male) who just underwent an ACL allograft reconstruction and medial meniscectomy for  a medial meniscus tear.  See the image below for an illustration of an ACL tear.


When I asked the patient how his injury occurred he replied, “I tore my ACL doing a plyometric workout with the personal trainer at my work.”  Ouch!  Naturally I wanted to know more.  So, I pressed him for more information – things like:

  • What kind of plyometrics
  • How many
  • Were they at the beginning or end of the session
  • How long had you been doing them

Let me tell you that a lot of therapists would not have asked these questions.  They would have moved on in the evaluation, dismissing this trainer as an incompetent fitness pro in their mind.  The fact of the matter is that bad things do happen at times even when we are doping everything just right so I like to give people the benefit of the doubt in most cases.

However, some of his answers led me to believe this particular trainer needed further education.  My client said the entire 30-40 minute workout was plyometrics. He was doing single leg multi-directional hops, but actually tore the ACL during a broad jump.  He mentioned he had only done a handful of the workouts before getting injured.  The kicker was when I asked him if anyone else in the class had been injured, and he remarked that another man recently tore his Achilles tendon.

Continue reading…

It has been known for years that increased coefficient of traction can predispose the knee to catastrophic injury.  Hence, the reason we got rid of all the old style astro turf in football stadiums.  But, traction is influenced by the sole architecture of the shoes as well as the playing surface.  Unfortunately, we are not fully aware of how exactly the sole architecture or this increased traction can lead to injury. 


Nike Astro Turf Shoe


Does footwear really matter?  I say YES.  Case in point – I am not a big fan of Nike Shox because they position the ankle in a plantar flexed position, thereby making it so much easier for ankles to roll inward with cutting.  I have seen too many female athletes suffer inversion sprains while running suicides or training in these shoes.  I simply believe the design creates a biomechanical mismatch and elevated risk for ankle sprains.

Now what about traction?  A study in the American Journal of Sports Medicine by J Wannop et al. recently looked at the difference between two shoe designs in a controlled laboratory study.  The tread types of shoes used were either smooth or tread. 

The shoe used in the study was the adidas Response 2+ CPT (smooth shoe) and adidas Response=2(A) (tread shoe).  The traction testing was performed using a robotic testing machine, while the researchers also observed 13 recreational athletes performing 45 degree V cuts in both shoes.  Data was collected using 8 high speed cameras and a force plate.

The results are not shocking.  The highlights are:

  • The coefficient of translational traction and peak moment of rotation were both significantly higher in the tread show compared to the smooth shoe.   
  • In addition, the high-traction shoe had much higher peak ankle externalrotation moments, peak knee external rotation moments, peak knee adduction moments, and knee adduction angular impulse compared to low-traction shoe.

The findings of the study indicate that the resultant joint loading increased 12% in the ankle (transverse plane) and 13% and 20% in the transverse and frontal planes for the knee.  This increased traction is certainly enough to push the knee into the previously reported mechanical rupture zone.

What we cannot deduce is whether the increases in joint loading is strictly attributable to the higher linear and rotational traction or if there is even a linear relationship between them at all.

You should also note that athletes often choose traction shoes for enhanced performance.  In this study, there was no significant difference in the performance measured between the two groups.  So, we are left to ponder whether we really need higher traction shoes at all.  Future studies will need to address this relationship as preventing knee and ankle injuries just by adjusting footwear seems like a no-brainer if the science supports this.

It is fairly well accepted in medical/rehab circles that much of the lateral knee pain felt by runners is related to the IT band.  Researchers report that frictional forces are greatest between 20 and 30 degrees of knee flexion (this occurs in the first part of stance phase with running).   But what about the differences in hip and knee kinematics between healthy and injured subjects?

I currently train two competitive female marathoners.  Both are in their thirties.  One has run Boston and the other is training with me to qualify this year (she missed by 36 seconds last year).  Many female runners deal with iliotibial band issues during their training.  My client trying to qualify for Boston has issues on her right side.  My other runner does not.  The client affected by this also has some ankle instability which certainly affects closed chain mechanics.

Historically, researchers have felt increased rear-foot eversion has contributed to such injuries.  Why?  well, increased rear-foot eversion leads to increased tibial internal rotation, and by the ITB’s attachment point distally on the tibia this would in turn increase strain.  In addition, it has been postulated that gluteus medius weakness leads to greater hip adduction moments and undue strain.

One recent prospective study done by Noehren et al. concluded that runners who developed ITBS exhibited increased hip adduction and knee internal rotation angles compared to healthy controls.  Today, I wanted to briefly update you on a study just published in the Journal of Orthopaedic and Sports Physical Therapy looking at the running mechanics of those with previous bouts of ITBS and those without.  The study observed 35 healthy female runners and 35 age matched runners (ages 18-45 who run no less than 30K/week) with a history of ITB issues.  They measured:

  1. Hip, knee and ankle kinematics
  2. Internal moments during stance phase

So, what did the results say?  In a nutshell, the ITBS group did in fact exhibit increased hip adduction angles and peak internal rotation angles at the knee.  There was , however, no significant difference among groups with respect to the rear-foot eversion.  This particular study did not measure hip abductor strength.

As far as limitations to the study, one primary one was the fact that the ITBS group was healthy during the study (meaning they had some time in the past suffered ITBS).  With that said, the results did mirror the prospective study by Noehren.

The practical takeaways for runners and trainers are:

  • Prior ITB issues may increase risk for recurrence due to increased strain
  • Prior ITB issues indicate atypical hip and knee kinematics may be present
  • The rear-foot position may have a lesser role in causation of ITBS
  • Addressing hip stability, strength and eccentric control is paramount to injury prevention
  • Observing frontal/transverse plane knee mechanics is prudent

In training, I recommmend video analysis or using a mirror independently to observe what I term a single leg hop and stick maneuver.  I teach it to all my cutting and impact athletes.  Simply begin on the left leg and hop forward onto the right and lower down into a lunge type single leg landing position.

Observe the foot/ankle, knee and hip as the body declerates.  This image and sequence of events leaves strong clues about the strength and force dissipation that is or isn’t happening.  Perform at least 3 trials and repeat on the other side.  This evalaution technique then also becomes a training tool to correct imbalances and improve deceleration mechanics – the very essence of the injury problem to begin with.

I routinely have my athletes with assymetrical or atypical kinematics engage in this drill no less than 2-3 times per week.  I have them perform 2-3 sets of 5-10 quality reps on each side (alternate sides).  Focus on preventing the femur from adducting too much or the patella moving inward.  In addition to this drill, obviously include steady glute max and medius work in your programs to help reduce ITBS.  With all that said, happy running!