Chanman's Blog


When to retire running shoes

Posted in Coaching by Andy Chan on January 11, 2011
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Did you get a new pair of running shoes for Christmas? Is purchasing a new pair of running shoes on your New Year’s to do list? A common question among runners is, when is it time to replace an old pair of running shoes. As a veteran runner, I seem to just “know.” I can feel that the shoe feels worn out. Or my internal shoe pedometer knows it’s been 300-500 miles. What concrete advice can I give you for determining when it’s time to retire a favorite pair of running shoes?

The gold standard that I hear all the time is that running shoes will last 300-500 miles (some people will tell you 350-550 miles). While logging your miles in your training log, also log your shoe’s miles so you know when you are in that 300-500 mile range. The problem is that’s a wide range. If you are well-built (i.e. heavier than the average skinny distance runner), your shoes may last closer to 300 miles rather than 500 miles. Terrain also plays a factor. Hard concrete and asphalt surfaces wear shoes out more quickly than soft trails and grass. The 300-500 mile range is a guideline but it won’t tell you specifically when it’s time to retire your shoes.

Areas where you can look for wear on your shoes include the outsole and midsole. There are distinct grooves in the rubber outsole on the bottom of running shoes when they are new. As the shoe gets worn out, the rubber on the outsole gets worn smooth. The heart of the shoe, however, is the midsole. This is where your cushioning and support come from. When the midsole wears out, is when you start getting injured (minimalist shoe arguments aside). A sign that the midsole is wearing out is when cracks, wrinkles, or creases appear in the midsole, usually under the heel or ball of the foot. I found an article on about.com in the sports medicine section that is brief and specific in its advice about when to replace running shoes.

The outsoles of running shoes. Notice the distinct grooves of the new shoe (top) versus the worn out/smooth bottom of the old shoe (bottom).

Cracks, wrinkles and creases in the midsole of an old shoe.

 

The midsole of a new shoe - no cracks, wrinkles, or creases.

I believe that walking around in running shoes wears them out quickly. I believe that spending the whole day in your running shoes imparts more wear and tear on them than an easy four mile run. This is why you will see me changing in and out of my running shoes before and after a run. I also superstitiously believe that driving (stepping on that gas pedal real hard and all!) wears out running shoes.

I wear specific shoes when I coach. I used to wear old running shoes to cross country meets since I wasn’t going for a training run at the meet. But recently I realized that at a cross country meet I tend to sprint all over the course to cheer. Cheering can basically be a four or five mile fartlek workout. Even at a track meet I am on my feet walking around for eight to ten hours, covering three to four miles walking back and forth from one place to another. I don’t want to wear my best training shoes for meets because I will wear them out. But I also don’t want to spend all those hours on my feet, sometimes sprinting all out, in a pair of worn out shoes that will leave me with sore feet and legs from lack of support, stability, and cushioning. For coaching I buy a mid-priced running shoe. I have read no research to back it up but I believe that coaching at meets for one year will wear out these shoes, so I buy a new pair of “coaching shoes” once a year.

Having multiple shoes is definitely recommended for all runners, not just coaches. A 2006 Running Times article by The Shoe Guy explained the details of why having multiple shoes is important. If you read the article, I can assure you that despite any resemblance you may find between me and the character “Age-Grouper Andy” mentioned in the article, I don’t know The Shoe Guy so I don’t think the character is based on me. The main reasons for having multiple shoes are:

  1. Rotating between shoes allows the shoe to “rest.” That gives the shoe time to dry. Wet shoes are a great environment for bacteria and fungus, which can lead to athletes’ foot and other maladies.
  2. The midsole of the shoe is made of foam. When you run, this foam gets compressed and it can take up to 24-48 hours to uncompress or re-expand back to normal. Running in the shoes before the foam has uncompressed puts you at risk for injury because the midsole will not provide its normal support, stability, and cushioning.
  3. Having more than one pair of shoes (assuming they are not the same model) forces your body to adapt to slightly different mechanics because of differences in the shoes. You end up spreading out the stress of running on different muscles, tendons, and ligaments.
  4. I like having different shoes for different workouts. That way you take advantage of each shoe’s specific strengths. For long runs I like a stable shoe that I know will give me a lot of support. For tempo runs and fartleks I like to use a lightweight trainer so that I can go faster with less energy expenditure since I am carrying less weight. I get less support with a lightweight trainer but my tempo runs are shorter so support is less important. For races I like racing flats. They may offer minimal support but since I only wear them to race in, I am not actually running many miles in them. My mechanics tend to be better during a race because I am running fast so I need less help from the shoes to keep my biomechanics smooth. Plus, racing flats are super light so I feel fast!

Having multiple shoes requires an initial investment but can save you money in the long run. In his book, The Competitive Runner’s Handbook, Bob Glover says, “Studies show that by alternating two pairs of shoes they’ll last longer than three pairs used consecutively.” He also says, “Rotated shoes retain 80% of their cushioning after sixty runs of an average of 5 miles (300 total miles) compared to only 60% for those not rotated.”

I suggest you go out and buy a new pair (or multiple pairs) of running shoes. If running is important to you then it’s worth it. A $100 pair of shoes that lasts 400 miles costs $0.25 per mile. That’s $2.00 to run eight miles. If that eight miles takes you 64 minutes (8:00 per mile pace), the cost of the shoe is $0.03 per minute. What a bargain!

Lastly, when it is time to retire your running shoes, please consider donating them to a place like Soles 4 Souls or Shoe4Africa or taking them to a shoe recycling location like Sports Basement in the San Francisco Bay Area.

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