Monday, April 28, 2003

Nonergonomic! Athletic Footwear and Chronic Overloading

Nonergonomic! Athletic Footwear and Chronic Overloading
[人因工程 ]

Athletic Footwear and Chronic Overloading

Some authors have concluded that chronic overloading with locomotion is inevitable in modern man because of inherent lower extremity fragility. Accordingly, footwear, such as running shoes, which attempt to attenuate shock waves through interposition of yielding layers between the plantar surface and ground, are presumed essential for safe running, and are also promoted for use during walking. However, this supposition seems inconsistent with reports indicating that habitually unshod humans are not subject to chronic overloading during running. By taking this into account, the lower extremity must be inherently durable, and chronic overloading must be a consequence of wearing footwear, and probably due to increased shock with their use.

It has been observed that locomotion in barefoot-adapted subjects (normally unshod, or customarily shod after allowing several weeks of barefoot adaptation) differs from customarily shod subjects in that those barefoot adapted 'grasp' with their digits when they walk...

Obviously, the ideal solution to the running related injury problem in shod populations lies in barefoot locomotion, since protective adaptations seems to be optimized for this state. Normally shod people would have to allow sufficient time for adaptation of the plantar skin and intrinsic foot musculature (perhaps 6 weeks), and run barefoot frequently, perhaps daily, to sustain this adaptation. However, once adapted, the foot is extremely durable.

See Illustration: Abebe Bikila, Marathon Winner, 1960 Rome Olympics. At the Tokyo Olympics in 1964, Bikila became the first person to repeat an olympic marathon victory. Bikila set another world record at 2:12:11 and became the first marathoner to finish the race under 2:13.

The lower extremity is inherently durable, and, when unencumbered by footwear, it can endure running without signs of chronic overloading, because a vigilant system restrains shock. The use of modern athletic footwear, in addition to being inferior to older footwear in moderating shock during running, renders the lower extremity susceptible to injury because of design flaws introduced by the preoccupation with optimization of plantar comfort.

The obvious solution to the problem of chronic overloading in shod runners is to promote barefoot running.

Editor's Comments:

The authors' solution to preventing injuries artificially induced by "ergonomic" footwear is to get rid of footwear altogether. Their solution is admittedly radical. But just because it is radical doesn't mean it's wrong. Radical is not a synonym for "crackpot".

Needless to say, industrial designers in the employ of footwear manufacturers are never going to go along with the authors' suggestion, regardless of whether it is scientifically validated. Even industrial designers not beholden to footwear manufacturers, and willing to "think outside the box" may find it difficult to accept the authors' solution.

But these are hardly the only alternatives. One need not endorse the authors' radical solution to acknowledge the persuasiveness of their analysis. I myself am unwilling to go about barefoot in most urban settings. I prefer to hold out for some workable compromise, one which allows my feet to move naturally while protecting them from broken glass, rusty nails, even hookworm parasites in pet droppings. Note that I have deliberately avoided raising the highly subjective issue of bare feet and social convention, as that complicates the issue even further.

Coming up with a workable, real world solution that satisfies a multitude of conflicting design considerations is easier said than done. But to continue down the tired, discredited path toward "ergonomic shoe design" is flagrant self-deception. It is akin to searching for your lost key under the street lamp when you know you dropped it in the dark alley, merely because it is easier to see in the bright light.

-- Bevin Chu

Explanation: Athletic Footwear and Chronic Overloading
Illustration(s): Abebe Bikila, Marathon Winner, 1960 Rome Olympics
Author(s): Steven E. Robbins, Gerard J. Gouw, and Adel M. Hanna
Affiliation: "Athletic Footwear and Chronic Overloading," Sports Medicine, 9(2), 1990, pp. 76-85.
Publication Date: December 27, 1996
Original Language: English
Editor: Bevin Chu, Registered Architect

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