Spring is here and many find the good old running shoes to get in shape. Many are very eager and run more the first month than what they have done together this past year. The result is often "injury injuries" and other "injuries" that stop the race career for a while and in the worst case scenario until next spring.
When the injury is a fact, many people resort to a personal trainer and assume that better racing techniques will do the job. It can help, but if you have an injury, it is important to contact one with a physical and / or sports-related college and not a studio trainer with a course certificate from a sports shop. If you are really unlucky with the choice of coach or coach, you can end up with exercises and training that make the injuries worse. A wise man with long experience once said to me about changing course technique:

If the boat goes straight into the water, do not rock it. Jacob Juul Hastrup

Instead, look at what you are running and where you run. Old, worn and bad sneakers combined with monotonous running on asphalt with a few kilos extra can quickly result in ailments and eventually injuries.


Most running shoes are molded with several types of layers in the sole under the shoe. Manufacturers build their shoes in different ways to provide an optimal running experience.
For example, the outermost layer of knots can be composed of durable rubber on the full, soft midfoot for good grip and low friction as well as aggressive knuckles focusing on kick-off in the forefront.
The various intermediate layers into the actual shoe sole often have a base of viscose with the addition of gel padding, air or spring damping. This contributes to the creation of features in addition to cushioning such as stability, trampoline effect, pronamas adaptation, plate for protection against sharp objects, etc ...

Meaning and research

Research shows that the midsole in a running shoe gradually loses its elasticity and shock absorbing properties when used. When the midsole begins to fail, the shoe loses its intended support and foot protection. Over time, this will affect the rest of your body in the form of irritation and pain in your back, hips, knees, legs and ankles. Pain in the legs may also be muscular fatigue that may be associated with diminishing traits in well-used running shoes.

  1. An elderly research study conducted at various manufacturers' running shoes at Tulane University charts the shock absorption function of viscoelastic material on a running shoe. The study showed that with a "mechanical foot" disappeared 40% of the original shock absorbing function between 400 and 800 km. With real runners, 20-30% of the shock absorbing function disappeared after 800 km. This study will still be important because viscoelastic material in the sole of running shoes is still being used.
  2. A recent study from the University of El Paso-Texas shows that there is no significant difference between the midsole's composition of gel padding, air or spring damping.
  3. At the Chemnitz University there have been two studies with relevance in the field. One confirms that there are differences between mechanical and test methods made by actual runners to quantify shock absorption properties for running shoes.
    The second study of thirteen shoes from nine manufacturers showed that running shoes lose stiffness and shock absorbing ability already after 300km. A funny observation from this study is that those who participated in the test unquestionably adjusted their landing pattern to compensate for the weakened shock absorbing ability of the test bowl.
  4. An extensive depth of field in research on running shoes and midsole is from the University of Essen at Professor Hennig and his 18-year performance study of running shoes. The study included 156 running shoes worn and used by runners from 1991 to 2009. Here Professor Hennig concludes that high quality running shoes maintain good stability and attenuation even after 1000 km.

Well, the diminishing shock absorbing properties are not easy to see and it's hard to find a fence when you should switch. There are many elements that play in; runner weight, muscle mass, substrate, environment, heat etc.


Here are some simple checkpoints that may help you to evaluate whether your running shoes should be replaced:

  • Put your old shoes on a table and look at them from behind for bias.
    • Also check if there are spaces in the middle sole that have "colmed" or been compressed. Particularly exposed area is under toeball and helicopter.
  • Is the body itself worn out, expanded or has holes?
    • Then the foot will not sit well.
  • Is the insole worn out?
    • This causes friction, snout and blisters. May be due to poor adaptation or lack of joining of shoes.
  • Is the sole under exhausted?
    • The shoe loses the ground with which you run.
  • Go to the sports shop and try a pair of similar - but new shoes.
    • Is there a significant difference between the damping?
  • Turn on the shoe and notice if there is still good resistance.
    • Is there a significant difference from a new shoe?

By studying a pair of worn out shoes and wear patterns, it will be possible to map footsteps and footsteps, which may help with the purchase of new shoes.

Choice of new running shoes

Should you have a pair of good running shoes, you should go to a sports shop with good competence and the best possible range of running shoes. Running shoes are a bit like a car: Each shoe has its unique features, fits best on specific surfaces and has a different fit.

Pictures and lining are replaced when worn out. It should also apply to your running shoes.

The price of a pair of running shoes is often an indicator of what the manufacturer has put in work to get them developed, no matter how good they are for you. What's amazing running shoes for me will probably not be great for you. When choosing shoes, there is much to play in; personal feelings, body shape, weight, muscle mass and some distinctive feet with genetic characteristics such as high elbow, long toes and broad forefoot. If you top it with running style, balance, pain tense and bet level, it's easy to understand that running shoes are an individual thing and must be tested to find your shoes.

Running analysis is fresh produce

Have you done a race analysis and received expert opinions on what category of shoes that suits you best, this will not be the stage for what you need this year. Your age, posture, muscle mass, balance, tension, stiffness and elasticity are just a few factors that change over time.

Buy more shoes

By rolling on different types of shoes you will probably be both stronger, faster and less vulnerable to injury. When changing shoes, your interaction with the terrain will also change. Muscles, joints and tendons move slightly differently, which gives variety and reduces loneliness with subsequent stress and wear.

Number of kilometers

Before statistics, see how far you've run with your individual running shoes. To make it easy, you can use Endomondo, Garmin Connect, or other apps for this.

If you have a lot of wear on your running shoes, do not worry. You are about to be a better runner.


I can probably drive 800 kilometers before my running shoes are worn out, but the joy of running is so important that I replace them a lot earlier.

Have a nice run.