Defective Running Shoes as a contributing Factor in Plantar Fascitis in a Triathlete
Wilk B, Fisher K, Guitierrez W: JOSPT 2000;30(1):21-31
Overview: Case study of 40 yo male triathlete who developed R sided plantar fascitis after completing a half ironman (2K swim, 90K bike, 21K run). The study describes the factors contributing to the injury, the rehab process, and shoe construction along with the symptoms of plantar fascitis.
Authors Conclusion: A running shoe manufacturing defect was found that possibly contributed to the development of plantar fascitis. Assessing athletic shoe construction may prevent lower extremity overuse syndromes.
What The Gait Guys Say: Plantar fascitis is something we see clinically many times in our practices. It is often due to overpronation of the midtarsal joint (talo-navicular and calcaneo-cuboid) in midstance, with insufficient supination from late midstance through preswing. Thus, this over pronation causing overloading of the plantar fascia and windlass mechanism, resulting in increased torsional forces and micro-tearing at it’s proximal calcaneal (and sometimes distal) attachments. This causes local pain, swelling and inflammation, particularly at the calcaneal attachment site, which is alleviated by rest, ice and analgesics. As we have shared many times now, this over pronation does not have to be a local cause, it could be necessary from insufficient internal rotation of the hip or from other factors.
In this study, the Right shoe upper was canted medially on the midsoles, believed due to it not being glued perpendicularly (as we often see inspecting a shoe from behind, especially Asics Kayano’s in our experience). The authors state they felt this contributed to excessive inward rolling of the right foot, contributing to overpronation.
The authors make the following recommendations about shoe inspection:
- The shoe should be glued together securely
- The upper should be glued straight (perpendicular) onto the midsole. The shoe, viewed from behind should have a horizontal heel counter and vertical upper
- The sole of the shoe should be level to the surface on which it is resting (ie no medial to lateral motion should be present) You can test this by attempting to “rock” the shoe from side to side
- The shoes should not roll excessively inward or outward when resting on a level surface (ie when rolling from P to A) You can test this by rocking the shoe from A to P
- Air and gel pockets should be inflated evenly. This can be tested manually by pressing into them and checking for uniformity.
A nice rehab protocol is also outlined over a 4 week period.
Bottom Line: It pays to be shoe nerd. Shoes can help or hurt. We see manufacturers defects in shoes every day and tell clients to return the shoe; in fact some we collect to use to show people. A rearfoot varus in a shoe will help to slow pronation. This may actually be beneficial for overpronators but detrimental for supinators. Some defects can be helpful but try and find defect free shoes. Stay away from “2nds” at cheapie stores and online specials. There is usually a reason they are being sold so cheaply. EVA’s have a shelf life and will break down over time. You must be able to not only recommend the appropriate shoe for your patient, based on their evaluation and gait analysis, but you need to inspect their footwear carefully and teach them to do the same.
The original shoe nerds….Shawn and Ivo