When to say my running shoes goodbye?

Question

How to find out that my running shoes need to be replaced?

I've switched recently from hiking to the trail running. I've hiked with the membrane shoes, which was quite an obvious indicator - if the shoes are no longer waterproof, they need replacing. Of course broken or worn down sole was also an indicator, but the waterproofness was normally first to go.

Now I'm mostly running with non-waterproof shoes. Garmin connects suggests saying goodbye after 600 km, which seemed to be exaggerated for me. My shoes have already 1000 km on the counter, the soles are OK, the only thing that changed is that the inside feels not so comfortable as at the beginning, but it's a problem only with thin socks. In the thick socks I feel no difference.

Is it a good idea to wear the shoes until they really break, or there are some aspects affecting safeness / stability that I'm overseeing?

Answer 1

There is a common belied that (1) running injuries are caused by running too many miles or by having the wrong shoes. If you believe this, then it might be logical to speculate that (2) wearing the same shoes for too long will make you get injured, since the shoes might lose their cushioning ability, and that might then cause injury. But actually when people have looked for evidence of 1, they've mostly found that it doesn't seem to be true, and if 1 is not supported by evidence, then 2 doesn't make a lot of sense.

Of course the companies that sell running shoes would like you to believe 2.

I just buy new shoes when my old ones start to get holes in the toes or fall apart. My records are a little fuzzy, but from the rate at which I buy shoes and the number of miles I usually run, I don't think I'm getting more than 300-500 km from a pair of shoes. 1000 km sounds like a lot. I'm talking about nylon mesh running shoes. I wear my running shoes to work, for hiking, when walking the dogs, etc., so a lot of the wear would not have been from running. My actual mileage per week is usually about 10 to 30 km, unless I'm sick, injured, busy, etc.

References

Thiesen, Influence of midsole hardness of standard cushioned shoes on running-related injury risk, http://bjsm.bmj.com/content/early/2013/09/16/bjsports-2013-092613.abstract

Shorten, "The heel impact force peak during running is neither 'heel' nor "impact" and does not quantify shoe cushioning effects"

Saugy et al., "Alterations of Neuromuscular Function after the World's Most Challenging Mountain Ultra-Marathon"

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0065596 -- described in "Running 100 miles? It may be easier on your body to go 200," http://articles.latimes.com/2013/jun/27/news/la-sn-ultra-marathon-20130627

Nielsen, "Classifying running‐related injuries based upon etiology, with emphasis on volume and pace" http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3625796/

Rasmussen, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3625790/