Monday, October 24, 2016

Arches And Orthotics

Picture from article Scientific Reports
I've often been asked by my patients about whether they need orthotics. The following article I read will explain some of the research behind orthotics on how they can affect your running rather than just my opinion.

Each time we land on our arches when we run, energy is stored in our arches. This is free energy that doesn't require anything to activate. The researchers wanted to measure wanted to find out specifically how much energy is lost if they restricted the arch with orthotics.
Orthotic that was used
The researchers made two types of custom orthotics. One completely blocked the arch from collapsing while the other allowed the arch to compress (or collapse) halfway. Only runners who did not use orthotics were recruited for their study. The runners ran on a force plate treadmill. The shoes had sensors inside which measured energy expenditure.

In order to have a baseline measurement, the runners ran in just the shoes (that were similar for all runners, pictured below) first followed by the same shoes at the same speed while testing the home made orthotics.

Picture from Scientific Reports

The runners tested the orthotics while walking as well as running.While walking, there was virtually no difference in energy expenditure. However, while running significant energy loss occurred.

In the orthotics that blocked all compression, researchers measured an energy cost of six percent (or less efficient by six percent) while the orthotics that allowed for 50 percent compression lost four percent.

Before you throw away your orthotics (if you're wearing them) the authors suggested don't throw them out yet as many runners get custom made insoles to prevent injury. They felt this is more important than saving energy without the orthotics. In fact the authors were very diplomatic and said that "We don't want to say orthotics are good or bad."

Likewise, if you are considering wearing orthotics (but may not need them), then maybe you shouldn't especially if you wanna run faster.

Reference

Stearne SM, McDonald KA et al (2016). The Foot's Arch And The Energetics Of Human Locomotion. Scientic Reports 6, Article number: 19403. DOI: 10.1038/srep1940.

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