In a fairly old study, Cook, Kester, and Brunet at Tulane University examined the degradation in mechanical shock absorption in a variety of different shoes.1To buy more Mens Nike Free 4.0 V2 with cheap price, you can visit shoesshox official website.

First, using a “running machine” which simulated the impact associated with running hundreds of miles in a pair of shoes, the researchers tested in a controlled way how the shock absorption changed over time.Then, they compared these artificially worn shoes to shoes worn by actual runners over an equivalent volume of running.

In the machine-simulated running, shoes had decreased to 75% of their initial cushion after only 50 miles; this cushioning dropped to 67% after 150 miles and ultimately to 60% after 500 miles.

The shoes worn by the real runners also declined in cushioning, following the same pattern of rapid decrease in cushion initially, tapering off and nearly leveling out at 500 miles of running.

But when worn by real runners, the shoes only dropped to 80% of their initial cushioning—good news for shoe-shoppers.Here’s something you probably want to know:The researchers found no significant difference in wear properties amongst many different brands.

The Nike shoes deteriorated just as much as the Adidas or Brooks shoes, despite each shoe boasting different cushioning technology.Finally, Cook et al. tested the “decompression” theory, which many runners have likely heard of.

Allegedly, if you alternate between two pairs of shoes to let the EVA foam decompress over 24 or 48 hours, you’ll retain cushioning in your shoes better. This turned out not to be the case.Granted, shoe design has changed a lot since 1985. And some preliminary research published in 2004 by Stefan Schwanitz and Stephan Odenwald in Germany indicates that changes in shoe cushioning as a shoe ages may vary between brands.2

But, while the evidence is clear that shoes do change significantly as they accumulate more mileage, does that mean that your running mechanics will change because of it?