The E-ffect of De-fects
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Improper footwear is a frequent cause for running injuries. Quite often a patient’s history reveals that, just prior to the onset of the injury, he had started to wear a new brand and/or model of running shoes. When this occurs, and in the absence of other obvious factors that may have contributed to the problem, I usually spend little time analyzing the reasons for a shoe’s culpability; I simply advise the individual to discard them and, if possible return to the model most previously used without problems.
Sometimes, however, the patient reports that she started to wear a new pair of shoes before the injury occurred, but it was the same make and model that she had been using without problems for years. My inclination is to dismiss the shoes as a potential cause for the injury, but a recent case study cited in the Journal of Orthopedic and Sports Physical Therapy serves as a reminder that this conclusion is not always correct.
The authors of this report describe a sudden onset of plantar fasciitis in a 40-year-old male triathlete. The subject developed the pain in his right heel soon after a 21-km run, the last portion of a half-ironman triathlon. History and exam revealed no previous episodes of heel pain and the patient had worn the same brand and model of training and racing shoes for more than two years. However, the racing shoes worn during the event were fairly new (approx. 48 km of wear). Examination of these shoes showed an asymmetry, with the right heel counter glued into the sole at an inward angle. (The left shoe appeared normal.) The authors postulated that this malalignment caused an increase in the runner’s pronation movement, leading to the plantar fascia inflammation.
As I read this report, I felt a gradual sense of déjà vu; about 20 years ago I had a comparable experience with a brand-new pair of shoes. Fortunately, the store at which the shoes were purchased was nice enough to exchange them for a new pair, even though I had worn them outdoors. The lesson I learned then is echoed by the authors of this report: runners should examine shoes for defects before wearing them and should return them if any are obvious. Some of the things to look for include:
- The shoe should be glued together securely. You should not be able to pull the upper away from the midsole or the midsole from the outsole.
- The vertical bisection of the heel counter should be perpendicular to the horizontal bisection of the sole of the shoe. If it is angulated in or out your biomechanics will be adversely affected.
- With the shoe resting on a level surface, the height of the rear portion of the sole should be equal on the inner and outer sides.
- Pushing downward with your finger or a pencil inside the shoe centrally where your heel sits should not cause the shoe to rock in or out.
Running shoes are assembled by people, not robots. There can be “lemons” out there; be sure to check them beforehand to keep your run from going sour.
