Thursday, January 20, 2011

Pelvic Biomechanics

Better performance is achieved by consistent training, and workout time lost due to injury will make reaching your goals much harder. This months performance tip centers on injury prevention. Given that overuse injuries are very common in runners, the early recognition of factors that predispose to injury is very important. The first concept to appreciate is that overuse injuries are the result of small amounts of damage summed up over a long period of time. A slight deviation in motion or strength can, over time, lead to a big problem. You may be happily running along for weeks or months without noticing anything, but the injury is slowly developing. When it does finally hit often the underlying problem goes undetected. After all, why would you suspect your foot to be the cause of your back pain?

Although there are many possible areas of abnormal biomechanics, a common one, sometimes overlooked, is the pelvis. Abnormal pelvic motion during running can put undue strain on a variety of structures and lead to overuse problems. However, before you begin cursing your pelvis, understand that sometimes abnormal pelvic motion is merely a result of a problem elsewhere. Looking at, and correcting, abnormal pelvic motion can help you discover these hidden problems.
To appreciate the abnormalities that may occur in running, picture a box around the pelvis (fig.). The two most common situations are,
  1. the pelvis is tilted forward (anterior tilt); slightly rotate the box forward
  2. one side of the pelvis is lower than the other (lateral tilt); slightly tip the box to one side.

Each of these abnormalities has its own specific range of problems, and sometimes both can occur.

So how do you find out if you're experiencing abnormal pelvic biomechanics? There are several clues to explore. Look at the wear on your shoes, if it is asymmetric, then you know that one leg is doing something different. This may not involve the pelvis but it is a consideration. Try this simple test. Perform a one leg squat, first with one leg and then the other. Go down to about a 90-degree bend in the knee. Watch yourself in the mirror. If balance is harder, or you find that one side seems weaker, tight, painful, or less coordinated, then you need to look more closely at pelvic biomechanics. If you have experienced any of the overuse injuries listed in the table, then you should definitely consider pelvic biomechanics.


To look specifically at what is happening requires outside assistance. An experienced running coach or runner can look at your form and give you feedback. Because some abnormalities are very subtle, video taping is often quite helpful. Once the abnormality is identified, then hunt for the associated tight or weak muscles, and/or related problems (e.g. overpronation, leg length discrepancy, etc...) and fix it.

Position
Anterior Tilt

Associated Injuries
 1.) Low back pain
2.) hamstring strain
3.) patellar tendinitis
4.) patellofemoral syndrome
-----------
And if the angle of gait is widened,
lower leg problems such as shin pain
Potential Cures

A) Abdominal muscle strengthening
B) Stretching and strengthening of gluteal muscles, hip external rotators, hip flexors, and hamstrings
C) Balance and retraining (e.g. one-leg squat)
  
 

Position
Posterior Tilt

Associated Injuries
 1.) iliotibial band friction syndrome
 2.) low back pain -- usually one sided
3.) adductor (groin) strains
4) lateral hip pain
Potential Cures


A) Look for leg length difference, overpronation in one foot, etc. and consider orthotics to correct.
B) Stretching and strengthening of hip adductors, abductors, extensors, and ext. rotator muscles.
C) Balance and retraining (e.g. one-leg squat)
 
Squat
One of the best exercises for runners, whether recovering from an injury or trying to prevent one, is the one leg squat.
 
Goals
  • Strengthen stabilizers (e.g. adductors)
  • Improve balance
  • Enhance pelvic stability
  • Demonstrate areas of weakness or instability

Method

Balance on one leg. Flex the knee of your non-weight bearing leg so that the foot is pointing toes down, behind you. This is a similar position to the recovery phase in running.


  1. Keep the arms loosely out to the side to assist in balance. Don't grab on to anything for support.
  2. Bend at the knee, and lower yourself. Go down to approx. a 90-degree bend at the knee, and then back up again.
  3. Keep your balance, and observe if you have more difficulty with one leg.
  4. Watch yourself in a mirror. Concentrate on keeping the pelvis in a stable plane. Look for an abnormal side-to-side tilt, or ant/post tilt.
  5. Usually, 3 sets of 20 for each leg is sufficient 
  6. As you get better at this, add some weight. You can do this with hand held weights, or a bar across the shoulders


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