Sunday, June 13, 2010

Going Bananas Over Shoes

I recently did a study for a shoe company where I was supposed to tell the anti-pronation shoes from the neutral shoes among four different shrouded shoes. It should have been a cinch for a biomechanics expert like me, right? I got all four shoes least according to the company and their classifications of the pairs of shoes. A dart throwing chimpanzee would have scored better. Then again maybe I got them all correct and they need to monkey around to reclassify the shoes.

According to the company the stability shoes (their term for any shoe containing an "anti pronation device") were as such because of a medial post (their term for a heel midsole with harder rubber on the medial side of the shoe than the lateral). The problem is that fortunately such a "device" won't really work and limit pronation. I say fortunately because my clinical observations say less than one in ten people need heel contact pronation limited. It does not work because 99.9% of runners have contact with the ground on the lateral side of their foot. The center of gravity stays lateral till well after mid stance on most people. Then it shifts more medial to anywhere between the big toe and the 3rd toe at toe-off. The point is that the medial block is just 'along for the ride" and does not come into play. If such a gimick worked, there would be a lot of very hurt runners out there because supination is far more injurious than pronation.

Still follow me? If you do, you are doing better than the R & D person at the shoe company whose eyes glazed over when I mentioned this. So all shoes are really neutral shoes, right? Not quite. Many of the neutral shoes have extra cushioning because convention "wisdom" in the industry dictates this. Shock absorption and anti-pronation are the marketing talking points. Extra cushioning also hides a multitude of rearfoot to forefoot functional transition shortcomings. You could say it helps smooth out the ride. It also makes body parts zig when they should be zagging. The brain compensates by firing certain muscle groups eccentrically to dampen the motion and right the errant body part. In essence, it cosmetically glosses over the short term while putting extra strain on the said body parts long term. So midsoles that are too soft are like putting lipstick on your "piggies."

So, anti-pronation shoes do not really limit pronation and neutral shoes randomly affect foot function depending upon the durometer of the midsole rubber under your personal center of gravity axis lines. Running shoe classification is not a science. It is an art. It is an art to limit the random avenues in the search your proper running shoe. What this means is be careful to trust less the company classification of the shoe and trust more what past experience tells you. If a model works out for you after a few weeks of running, go out and buy a couple more pairs of that shoe before they discontinue the model. Finally, make one of those pair into your "Sherlock shoes.