How fast do UNUSED running shoes lose their cushioning?

Depends on what conditions they're stored in. Check out the rubber on the tread- if it is dry and shiny, the shoe has been left in the sun or in hot temps, and the longevity of the shoe will suffer. If everything looks and feels like a new shoe, it is probably fine Shoes don't have a definitive shelf life like they did 20+ years ago.

Interesting.

The ones I've snatched up have been just fine - great condition.

So then, when I come across the 2009 model of my favorite training shoe for just $40, there's essentially nothing to lose in buying a dozen, and stocking them away in the cool dark closet for the next few years. Do you think they'll still be fine out of the box in 2015, 2016 at 6-7 years old?

That sure would save me a bundle on shoes.....

They lose 17 cushionings per year.

If you never use them, you'll never know, and it'll never matter

I would advise not buying 12 pairs of shoes at a time. I have stocked up on a favorite pair of shoes several times in the past when they were going out of production and they've always just collected dust in my closet. Any shoe you like now will not be the shoe you like the most in 2015. New versions will come out that you'll like more. Buy one or 2 extra pairs, but don't waste your money on 12.

My experience of loading up on shoes is that my preferences changed.

In fact, bulk buying/preference changing has happened to me three times.

1) Cairo->Adrenaline.

2) Adrenaline->H Street.

3) H Street->barefoot

So, buying a couple extras at a heavy discount might make sense, but ... you may not want to lock yourself in for all the 2010s.

That's a great question. Scientific research and observation by running store professional that I have read indicates a definite loss as little as within 6 months of production.

Personally I found a one or two year old unused running shoe stored in a closet to be indistinguishable from a much more recent shoe. I wouldn't go much past two years. If you look at foam under a microscope you will see it is actually lots of little bubbles filled with air. Over time, just sitting in a closet, the walls of the bubbles weaken. When pressure is applied, like in running, the bubbles burst. What this means is you'll have an almost unworn shoe that is completely unsuitable, and probably not enjoyable, for the demands of running.

I ran in a pair of unused shoes that were 5 years old that held up just fine. They felt like a brand new pair and wore at the same rate as a brand new pair. They were stored in a shoe box with the paper stuff inside, in a closet for most of that 5 years.

Lk wrote:

That's a great question. Scientific research and observation by running store professional that I have read indicates a definite loss as little as within 6 months of production.

Personally I found a one or two year old unused running shoe stored in a closet to be indistinguishable from a much more recent shoe. I wouldn't go much past two years. If you look at foam under a microscope you will see it is actually lots of little bubbles filled with air. Over time, just sitting in a closet, the walls of the bubbles weaken. When pressure is applied, like in running, the bubbles burst. What this means is you'll have an almost unworn shoe that is completely unsuitable, and probably not enjoyable, for the demands of running.

I recently picked out a pair of Saucony type A that I bought in 2007 and haven´t used. They felt just fine during my tempo run yesterday.

I basically agree, but it depends on the brand and the runner. From what I've heard and read, up to a year is fine for relatively efficient runners who weigh less than 150 lbs, but I tell my clients who are heavier than 150 lbs that they should not let running shoes sit longer than 4 months, especially not Asics or Brooks.

Be careful. They may feel fine, but you are begging for a foot injury if you keep using them. Especially for tempos. How heavy are you?

As a minimalist ('barefoot') runner I always greatly enjoy threads like these.

Very nice not to have to worry about stuff like this.

Keep it up! :-)

Hi all,

I just opened a box of Saucony Ride 2 I bought during a last-seasons-shoe sale in 2010! For $35 I stocked up, the current year were selling for around $100.

They feel great, just like the rest of my shoes. They were stored in a closed plastic tub in the garage. I have another pair in there too.

I wonder why people would actually think that the shoe degrades to the point of being, what they call in my business "Clinically Significant" .. rather than "Statistically Significant" .. e.g. I'm sure there are some small changes that occur over time that would be detectable in a laboratory - but that would not translate to actually making a difference running in them.

Where is the data on this?

Joe H wrote:

Hi all,

I just opened a box of Saucony Ride 2 I bought during a last-seasons-shoe sale in 2010! For $35 I stocked up, the current year were selling for around $100.

They feel great, just like the rest of my shoes. They were stored in a closed plastic tub in the garage. I have another pair in there too.

I wonder why people would actually think that the shoe degrades to the point of being, what they call in my business "Clinically Significant" .. rather than "Statistically Significant" .. e.g. I'm sure there are some small changes that occur over time that would be detectable in a laboratory - but that would not translate to actually making a difference running in them.

Where is the data on this?

There is no data. It’s a mixture of reasonable hypothesis, speculation, and myth. I’m sure shoe reps would tell you there’s some sort of degradation going on-“better buy a new pair to be safe”. If you can’t notice any problem, there is no problem.

Any plasticizers incorporated into the polymers used in the shoe could diffuse out over time which would change the mechanical properties of the material. This process will happen more quickly with plasticizers that are volatile, and if the shoe material has bubbles in it which would increase the surface area and promote plasticizer evaporation. Increased surface area due to bubbles would also increase oxygen and water transport into the shoe materials and therefore increase the rate of oxidative degradation and other types of chemical degradation. Increasing the temperature will make all of these effects happen more quickly, and light will also degrade the materials. So, the best way to keep shoes fresh over time is to store them in total darkness at high pressures and low temperatures in an environment of dry, nonreactive gas, such as nitrogen. Then your shoes will stay fresh.

I took my 1982 Mariahs out of the box and bent one, and the midsole turned literally to dust in my hands. The weirdo Freon gas or whatever probably shortened my lifespan a bit, too.

Quite right Ehso & Goodyear..

Substances do change with time, even our bones replace themselves every few years. But does it matter? There is so much myth out there with no data to back it up & not surprisingly the myths tend to favor spending more money on things (nutritional supplements, grass-fed, frequently hugged meat/produce, organic food, shoes no older than a few months, I "need" a $6000 mountain bike)

Not that a person might have other reasons for making these choices (e.g. might want the animals they eat ethically treated, might want to increase financial support of a footwear manufacturer), I have just not seen any credible data to support these practices from a general health or foot health perspective. Or a sponsored professional athlete might want an expensive bike as the 1/2 pound of weight savings might make a difference in race money earned or same with current running shoes.

Thanks for the input all. I'll feel confident on my casual run today!

If I decide to keep my shoes for a few more decades I'll be sure to pressurize a container with nitrogen as per Goodyear's recommendation :)