Preventing Runners Knee - Part II

With an increase in popularity of running, we are seeing more and more running related injuries.  This series is devoted to helping prevent one of the most common running injuries, runner's knee.  Although this is catch all diagnosis, last week we started a discussion around some common root causes for non-contact knee injuries in runners and how to prevent.  This week we will continue that discussion starting with how poor running mechanics can add to increase risk for injury.

• Faulty running mechanics – there are “a lot” of faulty movement patterns in runners that can result in problems in runner (arm swing, trunk rotation, etc).  Here we will cover some of the most common ones we see that add to increase risk for runners knee.

• Foot slap at heal strike.  In this scenario you will hear the foot slap the ground or treadmill.  Typically you get a thump, THUMP when comparing the sound of one foot contacting versus the other.  When this occurs, there is less shock absorption through the foot and ankle and this can lead to shin splints or anterior knee pain (runners knee).   A common root cause for this foot slap is weakness of the anterior tibialis or specifically, eccentric weakness of the anterior tibialis.  As a runner, you will start to feel fatigue in the anterior shin as you run.  As you continue the run, this becomes more intense and this is where you will start to hear the foot contacting harder than the opposite side.  Strengthening the anterior tibialis muscle in an eccentric fashion can help to alleviate or eliminate this.  With your toes hanging off the edge of a step, raise them all the way up (dorsiflex), pause, then slowly lower them to the starting position on a 3-6 count.  

• Over pronation from heal strike to midstance.  In a closed kinetic chain, like running, when the foot over pronates at midstance, this results in the femur moving into adducted and internally rotated position.  This significantly alters knee mechanics and increases stress to the soft tissue and bony structures of the foot and ankle and the knee.  Although most will try to control this with a shoe, we find better success with a well fit athletic orthotic.  A DPM or PT can do a running assessment to identify and fit with a proper orthotic.  In addition, adding strengthening to the intrinsics of the foot will help.  Couple of ways to do this: place a towel on a smooth surface (tile or wood floor) with a small weight on one end of a towel (#2).  Placing your bare foot on the other end of the towel, scrunch the towel up with your toes attempting to pull the weight toward you.  Another way is while standing bare foot on one leg with knee slightly bent and holding a light medicine ball in your hands (#3-#5), extend your arms out in front of you and toss the ball hand to hand.

• Knee adduction and internal rotation.  This will most commonly start at heal strike and become more pronounced at midstance.  In the absence of “over” pronation of the foot, this is most commonly the result of gluteus medius weakness.  Keeping in mind, in a closed kinetic chain, if the femur moves into an adducted and internally rotated position to a large degree, the foot will follow by moving into pronation.  So, the question becomes, is this a foot/ankle issue or is this a hip issue.  This is again where a through running and movement assessment can help to target where the root cause is coming from. Strengthening the gluteus medius will help a lot in preventing this.  The following are two great exercises for gluteus medius strengthening. 

Lumbar Hip Dissassociation 

Side Plank with CLX

• Hip Trendelenburg.  This occurs at midstance where the hip drops on the opposite side (depicted here).  This is the result of weakness of the gluteus medius on the stance leg.  The GMed has to contract to stabilize the pelvis during single limb stance (midstance in gait).  Weakness of this muscle results in the pelvis dropping on the opposite side and can put excessive stress through the hip joint (causing hip pain and impingement) and knee.  This altered movement will result in altered force absorption throughout the entire lower limb. Again, strengthening the gluteus medius is key to addressing this.  In addition to the above exercises, you can also add the following exercise.   

Side Stepping with Theraband  

• Limited flexibility/Mobility – Limited flexibility and mobility is another issue that adds to increase risk for runner's knee.  Since running is typically a single plane sport (not a lot of lateral or diagonal movement) this can add to tightnesses that can lead to increased risk for runners knee.  Some of the most common tightness’s associated with runners knee:

• Calves – tightness in the calves will limit the amount of dorsiflexion at the ankle.  With limited dorsiflexion will result in a runner who circumducts their leg during swing through.  This puts increased stress on the knee and foot and ankle.

• Quadriceps – tightness of the quads can lead to altered force absorption and lead to patellar tendonitis and patellafemoral syndrome. 

• Hip flexors – tightness of the hip flexors will limit how much hip extension a runner gets at toe off.  This can lead to an altered stride length and rotation of the hips at toe off.  Although this is a common cause for low back pain in runners, it can also result in runners knee.

• IT Band – although most say they will stretch their IT band, what you are actually doing is stretching your tensor facia lata (TFL).  The TFL attaches to the IT band.  If tight, this pulls on the IT band which puts friction on the lateral side of the knee when moving from a flexed position to a full extended position. 

For all these tightness’s we recommend stretching prior to your run and including stretching as a normal part of your routine.  Below are a couple we recommend for runners to do prior to their run.

Dynamic Lunge

Sumo Squat

We have found that combining stretches with high frequency vibration and/or percussion not only feels great to the runner but is also very effective.  There are several devices out there for that but one we use is the Hyperice Vyper (vibrating foam roller) and the Hypervolt (percussion gun). 

We hope you enjoyed this discussion.  Next week we will continue this discussion with talking about certain weaknesses that can add to runner's knee.  If you would like to find out more about how to get a 3D running assessment near you, contact us @ acl@selectmedical.com.  Stay tuned and please share with others you think might be interested.  #ViPerformAMI #DorsaVi #RunSafe

Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment and ACL injury prevention.  He is the founder | developer of the ViPerform AMI, the ACL Play It Safe Program, Run Safe Program and author of a college textbook on this subject.  Trent has performed >5000 athletic movement assessments in the US and abroad.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Vice Chairman of Medical Services for USA Obstacle Racing and movement consultant for numerous colleges and professional teams.  Trent is also a competitive athlete in Brazilian Jiu Jitsu.