Thursday 7 July 2011

Pain in the Hip....Or Knee

The Horrific IT Band

Almost anybody who has run on a regular schedule for an extended period of time has experienced either hip or knee pain.  Often, the cause of this pain originates from the iliotibial band or IT band.  In fact, the study referenced below indicates that IT band syndrome (ITBS) is the most common running-related knee injury, and accounts for up to 12% of ALL running injuries.  Essentially, if you have not experienced this injury, you aren’t running hard enough (just kidding).

The IT band (seen below) is a strip of connective tissue that runs from your hip, down to a bony prominence just below your knee.  At the top of this strip of connective tissue, or fascia, is a small muscle called tensor fascia latae.  This muscle functions primarily to bring your entire leg forward (hip flexion) or your entire leg to the side (hip abduction).
The IT band with tensor fascia latae above
And yes, if you are reading this blog, there is a good chance that you already know what the IT band is, that you have experienced ITBS, and you have already have received treatment for it.   Whether you suffer from symptoms at your hip or knee, common treatments include:

  • Rest
  • Ice
  • Stretching
  • The "dreaded" roller (see bellow)


Ouch! (if you've done this, you know what I'm talking about)


One Side at a Time
 
However, have you ever wondered why, for the most part, you get injured on one side at a time only?  After all, you use both legs to run, and take the same amount of steps with each side (±1, of course).  In fact, it is quite rare to simultaneously experience bilateral IT band pain. 

A study published in the Clinical Journal of Sports Medicine in the year 2000 looked to test one possible explanation- muscle imbalances.  These researchers looked at a leg action that you use with every step you take, and a leg action that is thought to be related IT band irritation-hip abduction.   

This is the act of bringing your leg straight out to the side (as if you are doing the splits).  If you are standing on the leg of interest, this action can also involve hiking your hip up (i.e. try lifting one leg off the ground without bending your knee or ankle on either side). 

What happens if one side is weaker than the other?  Many predict injury, and that is exactly what the study looked at.

Study

24 collegiate runners with ITBS were evaluated.  These were real runners, with real cases of ITBS.  Each runner was tested to see how strong their hip abduction was on both sides.  This is what they found:
Strength in injured limb (females): 6.86± 1.19 BWh
Strength in uninjured limb (females): 8.62 ± 1.16 BWh

Strength in injured limb (males): 7.82± 1.19 BWh
Strength in uninjured limb (males): 9.82 ± 1.16 BWh

Essentially, the injured side showed weaker hip abduction compared to the uninjured side in both the male and female runners. 

This makes sense from an anatomical standpoint as a runner will not be able to maintain a stable pelvis if their hip abduction is weak.  The authors note that, “it is postulated that this places the iliotibial band under increased tension and makes it more prone to impingement upon the lateral epicondyle of the femur...”  In other words, if you are not able to sufficiently abduct your hip, your are putting way too much stress through the IT band, and really increasing the chances of causing irritation in your hip or knee.

A very strong component to this study was that they not only looked for the imbalance itself, but they checked to see if correcting it would get rid of the runner’s pain.  Each runner conducted a 6 week rehabilitation program.  The focus of this rehab was the major hip abductor- gluteus medius:
Gluteus Medius- your greatest hip abduction ally.


Following this program, the females showed almost a 35% increase in strength on the injured side, while the males showed just over 51% increase in strength.  More importantly, 22 of the 24 athletes were pain free, and continued to be pain free 6 months later. 

By the way, these are two of the main gluteus medius strengthening exercises prescribed in the program:
1)   

Side Lying Hip Abduction
2)    

My Analysis 

Overall, this is a pretty exciting study.  These 24 competitive runners followed a very specific program and were able to eliminate a very specific muscle imbalance.  Then, even more importantly, when this muscle imbalance resolved, pain subsided and never came back.

One concern with this study, however, is that there is no control group.  In other words, only 24 athletes were involved in the study, and all 24 conducted a hip abduction protocol with their rehab.  The authors admit that, “it is possible that simply eliminating the pain or normalizing tight soft tissues led to increased facilitation of the hip abductors.”  In other words, there is no way to know from this study if the observed increase in strength and subsequent decrease in pain was exclusively due to the hip abduction exercises.

Closing 

If you suffer from ITBS, it is very likely that you need to improve your hip abduction strength on the injured side.  Is this done through strengthening exercises?  This article strongly suggests that may be the case. 

So do your hip hikes, do your side lying hip-abduction, and get rid of (and help prevent) the most common running injury! 

References:

Article:
 Fredericson, M. Et. al., 2000.Hip Abductor Weakness in Distance Runners with Iliotibial Band Syndrome. Clin J Sport Med. 10 (3) 169–175

Images:

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