We’re selling our soles for fashion

Out of style runners tossed out the window

KEEPING up with latest fashion trends might be why you’re looking to replace your runners, rather than actually needing to, a study has found. The findings came from a Deakin University study into the durability of runners’ shoes, which discovered they were typically worn in after 25km and didn’t degrade as quickly as previously thought. Dr Paul Collins, of the School of Engineering, said the ethylene vinyl acetate on the bottom of runners broke down quickly, and then settled and lasted much longer than many runners thought they did.

“The mid-sole foam of EVA breaks down all the weak bonds in the first 25km,” Dr Collins said.

“From there on, it’s solid material compressing on solid material, without the air bubble.

“While it can only compress so far, you do see a fatigue style of the mechanism of the material.

“Therefore, we think that runners can continue to use their shoes until other signs of shoe wear occur, such as deterioration of the rubber outsole or upper fabric.”

Dr Collins suggested the frequency at which people replaced their runners may be more about other factors, such as changing fashions from season to season.

Using human, rather than machine, testing, 12 runners went to the School of Exercise and Nutrition Science’s 3D gait laboratory for a 90-minute testing session as part of the study.

They each then ran 200km in their natural environment in the following weeks, returning for another 90-minute test in the same running shoes.

“While participants were running on the treadmill, we examined their running kinematics and kinetics with our 3D motion capture system,” said Rory Purdie, a researcher with Deakin’s Centre for Sport Research.

“By using retroreflective markers on participants’ lower bodies, we collected data, monitoring changes in angles of joints, measurements of generated force and time taken to get through different segments of their stride,” she said.