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Monday, October 25, 2010

Top 100 Biomechanical Guidelines: #3 The Weakest Link in the Chain is Effected

Here is another musical gift from Kapena from the Aloha Musical Festival near Waikiki Beach Sept 2010 singing Danny's Song.

     Multiple injuries are caused by each of the 4 major bio mechanical faults listed in the last post. They are over pronation, over supination, poor shock absorption, and leg length discrepancies. I will use one example of each to begin this discussion, but please realize the 33+ injuries have been shown to be related to over pronation, 17+ injuries related to over supination, and 10+ injuries each related to poor shock absorption and leg length discrepancies.

With over pronation, the heel twists from under the tibia called heel valgus or heel eversion, leading to an abnormal twist on the Achilles tendon with each step, leading to Achilles tendinitis. With over supination, the heel rolls outward like in an ankle sprain causing the peroneal tendons on the outside of the foot, ankle, and leg to overwork to stabilize and prevent ankle sprains, leading to peroneal tendinitis. With poor shock absorption, the foot and ankle do not perform their normal functions to reduce up to  1 to 2 times body weight at impact during walking, and 2 to 5 times body weight at impact during running, and the shock wave can jar the tibia leading to tibial stress fractures. With leg length discrepancies, one leg is longer leading to constant overwork of the muscles and tendons to right (center) the spine to keep the eyes looking straight ahead. The Achilles tendon on the short side can help with the compensation by lifting the heel more, but over time the Achilles tendon develops tendinitis.

So why does one patient with over pronation develop Achilles tendinitis and another plantar fasciitis or knee pain? Why does one patient with over supination (also called under pronation) develop peroneal tendinitis and another ilio tibial band tendinitis or low back pain? Why does one patient with poor shock absorption develop tibial stress fractures and another arthritis in their knees and hips? And why does one patient with a short leg develop Achilles tendinitis and another hip or low back pain?

The answer lies in the concept of "Weakest Link in the Chain." If you have abnormal motion like over pronation or over supination, the entire limb is stressed, but only one area will be the first that brings it

to your attention (the weakest link). If you have abnormal joint positions caused by being overly pronated or overly supinated, or having one leg longer than the other, the entire limb is stressed, but only one area will be the first that brings this to your attention (the weakest link). If you have poor shock absorption as you walk, the entire limb is stressed, but again only one area with complain first (the weakest link)

Athletes probably teach us the most about this topic since they ignore pain (No Pain No Gain Philosophy) the best. See my previous post on Personality Types. By the time they come into my office, they may have 3 or 4 injuries or sore areas at least going on all at once. The health care provider needs to determine what came first (the weakest link), and what developed as the 2nd or 3rd weak links, or merely due to compensations (favoring or limping or protecting with various muscle groups.

Definitely, if I was the supreme ruler of the universe (as I sometimes am on the basketball court!!), I would have patients come in with only 1 injury at a time. At least I can day dream as I sit here waiting for jury duty to begin.

What makes an area weak and prone to injury? The most common factors that we are always trying to correct are:
  1. Weak Muscles
  2. Tight Muscles
  3. Joint Looseness/Instability
  4. Joint Tightness
  5. Structural Abnormalities
  6. Previous Injuries/Tissue Damage (joint or soft tissue)
  7. Hypersensitive Nerves in the involved area
  8. Poor Bone Health
  9. Overstressed with Repetitive Stress
  10. Technique Faults (athletic or day to day)
  11. Equipment Faults (athletic or day to day)

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Thank you very much for leaving a comment. Due to my time restraints, some comments may not be answered.I will answer questions that I feel will help the community as a whole.. I can only answer medical questions in a general form. No specific answers can be given. Please consult a podiatrist, therapist, orthopedist, or sports medicine physician in your area for specific questions.