Sustainable running shoes - an overview for 2021

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sustainable running shoes 2021

Just like us, many runners are looking for environmentally friendly running shoes. First of all, the good news is that a lot is happening and we can expect a “thought through” solution in this decade. By “thought through” we mean a running shoe that does not harm the environment, perhaps even brings benefits on the contrary.

In this blog post we would like to give you an overview of what's currently going on in the space of eco friendly running shoes and what's coming in 2021. But first to the real problems.

 

The problems with conventional running shoes

Really a lot of shoes

 tons of running shoes

If a worn Nike running shoe is auctioned off at Sotheby's for $ 437,000 in 2020, it will certainly be evidence that running shoes have gained some importance. In the USA, almost USD 13 billion is spent annually on sports shoes, around USD 10 billion in China, 3 billion in the UK and around USD 2 billion in Germany. Worldwide it should be around USD 51 billion in 2020 (source: Statista). If we calculate with an average price of 100 EUR per pair, we end up with around 510 million pairs per year. Of course, these aren't all running shoes. But a considerable part of it is, according to Runners World approx. 40% and thus approx. 200 million pairs of running shoes in total per year.

Most also agree that we individual runners certainly buy too many pairs that we may not actually need. 8 active pairs of running shoes might make sense for runners who have athletic ambitions, but not for the casual runner who hits the road for 10 km 2-3 times a week.

 

What goes in: plastic plus questionable chemicals

plastic shoe

The number of pairs sold would not be a problem if they weren't made of such harmful materials.

The midsole is usually made of a TPU (thermoplastic polyurethane) or EVA foam (ethylene vinyl acetate). The foams are often chemically enriched e.g. with nitrogen or carbon dioxide to improve functional benefit. Occasionally, other materials are incorporated into the sole, such as the extremely light but very robust composite material carbon. A plastic in which carbon fibers are incorporated.

The tongue, i.e. the upper shoe that surrounds the foot, is usually made of various chemical fibers such as polyester and polyamide. Questionable catalysts are often used in polyester production, e.g. the not so healthy heavy metal antimony. The outsole made of a synthetic rubber or EVA. And other components such as laces, heel caps, inner sole elements and insoles are also made from a wide variety of plastics.

All of this has to be connected somehow. Various adhesives are used here, especially to hold the sole components together so that they can withstand the great stress of running.

And of course the materials also have to be colored so that the shoe looks good. In the dyeing process of fibers and plastics, the amounts of carcinogenic and dangerous substances (e.g. heavy metals) vary depending on the desired colors.

 

What is left: toxic waste and microplastics

Nothing good in the end

Landfill with plastic

Working with the above materials is not entirely harmless, especially with the adhesives and the vapors they emit. However, the big brands and their partner companies have done a lot in recent years to improve manufacturing safety in many factories around the world. Protective clothing and good ventilation systems ensure that people do not get sick. That is certainly good progress.

BUT: isn't this a paradox? The people who make these shoes must be protected from the toxic materials that are used in the shoes. When worn, the toxic substances may not escape directly to the outside in order to harm the wearer (opinions differ here too). But when all these substances eventually end up in a landfill (of course not all do), they are left to nature. Over the centuries, animals and microorganisms cannot do much with this piece of rubbish and its poisonous by-products, except perhaps to get sick or die from it. It is even said of TPU that it will only decompose completely in about 1,000 years (source: Utopia.de) .

Yes, in Germany and some other countries landfills in the classic sense are no longer allowed, but in many others they are. Alternatively, the shoes usually end up in the residual waste and thus in the incineration. Of course, the substances were not designed to be burned. Toxic gases and residues arise, some of which remain in the ashes (which, by the way, often have to be dumped somewhere as hazardous waste).

Incidentally, recycling a modern running shoe with so many different composites and materials is out of the question.

 

Pollution while running

Used running shoes

When we drive around in our car, the tires wear out. Every car owner must keep an eye on the tread thickness of his tires and change the tires regularly, depending on the volume of traffic and driving behavior. But where has the profile gone? Sure, the fine tire abrasion remains on the road and the rain washes it to the side of the road and thus often into the ground. Or the wind blows the fine plastic particles through the air. This is an average of 1,000 g of tire wear per German per year (Source: Fraunhofer Institute, Umsicht Studie).

It is no different with shoes. The average German leaves around 109 grams of sole wear on footpaths every year (Fraunhofer Institute). An active runner accordingly more. Observe how little profile your running shoe still has when you dispose of it. The TPU or EVA foam has probably also become partially porous.

The individual runner may say that the few grams don't matter.

Well ...

For fun, let's count on the above-mentioned 200 million pairs of running shoes per year and pessimistically assume that every pair of running shoes leaves 5 grams of its material on the road every year (the synthetic rubber outsole is often the heavier part of the shoe). That would be a whopping 1,000 tons of microplastic abrasion ending up in the environment worldwide, per year. In relation to this: a mid-range car weighs around 1.3 tons.


Current approaches for environmentally friendly running shoes

There is no doubt that the materials used so far are perfect for running shoes. They ensure that running shoes can be developed that are extremely resilient and can be designed in a variety of ways. They are also significantly lighter than the foot itself. Modern running shoes have a weight of 200 - 400 grams. This is not a lot and means that the athlete does not have to “drag” a lot of extra weight.

But the question is, can't you design shoes that are environmentally friendly?

The answer is yes, it can be developed. Many companies are in the process of approaching the problem through different ideas. So far, none of the approaches can be seen as the final solution, rather as the first steps in the right direction.

In the following we would like to introduce you to four approaches that are currently being pursued by running shoe manufacturers. We deliberately do not go into vegan running shoes in specific, because initially that has nothing to do with environmental friendliness per se. Vegan sport shoes can be made of toxic materials. So you (the planet) wouldn't have gained much from that.

As in many other industries, manufacturers have different approaches to tackle the issue. Basically, one can differentiate between the following approaches:

Approach 1: Use recycled material
Approach 2: Increase longevity or useful life
Approach 3: Use regenerative, biodegradable materials
Approach 4: Developing circular shoes

 

Approach 1: Processing recycled material - well meant, but only a postponed problem

Empty PET-bottle on the beach

Using “recycled” materials seems to be the oldest and most widespread approach. Most manufacturers are active in this area. What is meant is that you take plastic waste and use it again as material for new products. These wastes have different origins. It can be production waste, e.g. cuttings of fabrics or sole material (so-called “pre-consumer waste”) or consumer waste, e.g. old PET bottles (so-called “post-consumer waste”)

Benefits:

  • Ideally, nature is freed from non-biodegradable waste
  • Companies have lower costs because they do not have to use new raw materials if they can use production waste for new products
  • In some cases lower CO2 emissions than when using new material
  • Easily available and easy to use for marketing running shoes, as the user does not feel any change in the product

    Disadvantages:

    • If the recycled material is made up of environmentally harmful substances (most of the time it is), you just postpone the problem. Ultimately, the end user also throws away the shoe made from recycled material. This shoe cannot then be recycled again. So you take garbage to make new garbage out of it.
    • Old plastics that have been in water or the damp environment for years can be heavily polluted. In addition, many years ago chemicals were still permitted in plastics production that have long since been banned (BPA, plasticizers, etc.). It is questionable whether it makes sense to wear them on your sweaty foot or body in the long term
    • In order to produce high quality raw materials from recycled material, it often needs a high energy and / or chemical effort
    • Recycled “raw materials” are often shipped around the world. Specifically: PET bottles are collected in one country, shipped to another country in order to turn them into a usable material (recyclate), then a yarn is made from it, which is then shipped to another country to make a textile or a shoe.

     

    Examples

    We have attached a few examples of running shoes that use this common recycling approach.

    Nike Flyknit

    Nike is a pioneer when it comes to recycling production waste and also in the use of rPET, i.e. recycled polyester from old PET bottles. The polyester knitted in all Flyknit running shoes from Nike is now 100% recycled PET bottles. So far (2020) Nike has shipped over 4 billion old PET bottles around the world and processed them into new plastic products (https://purpose.nike.com/waste). There are other models in the non-running segment, which in turn accommodate up to 50% production waste. In the Space Hippie sneaker, e.g. shredded Zoom-X foam is glued and incorporated, on which Eliud Kipchoge ran his <2 hours record.

    In our eyes, however, these shoes, in which the upper shoe is made from recycled PET, cannot be described as environmentally friendly or significantly sustainable.

    Nike Flyknit made with recycled PET yarn

    Adidas Primeblue

    Adidas advertises its Primeblue products with “Because we care about the environment”. Primeblue is a polyester yarn that is largely made from old ocean plastic (collected in cooperation with Parley). The upper shoe of the Ultraboost 20 is partly made with the Primeblue yarn. The product description says “was made with Primeblue”, so it is not 100% clear which portion it is exactly. Here, too, we believe that the shoes are not really sustainable.

    Adidas running shoe made with Primeblue

    Brooks

    Brooks also relies on recycled PET and wants to switch completely to this material by 2023. Brooks has also developed a midsole that biodegrades faster than normal shoe soles. The BioMoGo sole is expected to decompose in about 20 years. At the same time, it should be more efficient than conventional EVA. However, the sole is not advertised very actively.


    Icebug

    The company Icebug from Sweden has long been concerned with the question of how they can be more environmentally friendly. They have it in their company DNA and everything they do reflects on being a reponsible company. Icebug describes itself as a climate-positive company. They achieve this through company wide efforts and above-average compensation investments (purchase of certificates to compensate for CO2 emissions). In addition, Icebug is working on all components of the shoe to manufacture them with better materials.

    They describe the trail shoe RB9X as “probably the most sustainable trail running shoe in the world”. The upper is made of 100% recycled polyester, the midsole made of EVA foam is mixed with algae and the lower sole is mixed with rubber residues. In addition, the CO2 emissions for this shoe are offset twice. LINK

    Icebug RB9X


    Approach 2: Increase longevity or service life - the runner thus produces less waste over lifetime

    Dirty used shoes

    This approach is geared towards the useful life of the shoe rather than the manufacturing process. The shoes should last as long as possible. Of course, two German manufacturers score points with this approach.

    Benefits:

    • The runner does not have to deal with buying new running shoes as often
    • The absolute amount of waste with running shoes is decreasing

    Disadvantages:

    • Durable does not mean environmentally friendly, because these shoes will also be disposed at some point and will be burned or buried
    • In order to make a product more durable, more materials may have to be used that nature would have to “nibble” on for longer if this shoe ends up in the dump. However, this does not have to apply across the board to these shoes.

     

    Examples

    Lunge Shoes 

    Lunge manufactures its shoes in Mecklenburg Vorpommern / Germany. The material is purchased in Germany and Europe and the shoes are made in their own factory. When selecting materials, Lunge pursues approaches which they describe as sustainable, e.g. use shredded CDs for the heel counter. A special feature in terms of durability is that the EVA content in the sole is around 80%. Due to the company this is quite high compared to other EVA soles. As a result, the cushioning in the sole remains longer than with other soles.

    A special clue with the Lunge shoes is that you can renew the sole. So you don't have to buy a new shoe straight away. Resoling costs 80 EUR, takes 14 days and must be carried out by a specialist retailer (usually orthopedic shops). Anyone who wears a running shoe for 3 years also needs a timeless design. The design of the shoe is rather less modern and can be described as the opposite of progressive. LINK

    Lunge Classic Run Running Shoe
     

    Runner Tune

    Runner Tune is a shoe manufacturer from south-east Germany. Part of the sole is made of cork. A sole change is also possible here. For 119 EUR, the entire lower and midsole is renewed and the shoe is brought back into shape on its last. The clue here, however, is that the shoe is made with an individual footbed. After you have ordered the shoe, a foam pillow is sent to your home, on which you have to leave your footprints. This is how the right sole is made in the factory. At around 500 EUR, however, it stands out in terms of price. Visually, these shoes, similar to the Lunge shoes, are rather less progressive. LINK

    runner tune running shoe

     

    Approach 3: Use regenerative, biodegradable materials - very good approaches in the early stage

    Cornfield

    Another approach is to replace non-biodegradable plastics with regenerative and / or biodegradable materials. The current most common practice here is to add plant-based components to the previous poly-based materials. No company has yet managed to do without plastic entirely. The midsole and the adhesives of the running shoe pose the greatest challenge here. The end product is still non-biodegradable, but the amount of plastic is reduced. Another approach would be to use plastics that are biodegradable and environmentally safe. To the best of our knowledge, however, there is no running shoe manufacturer who is currently pursuing this approach.

    Benefits:

    • The industry is reducing its dependence on oil, a non-regenerative raw material
    • Plant based raw materials grow back
    • Ideally, the shoe or individual components are biodegradable and not harmful to nature, should it end up in nature

    Disadvantage:

    • As soon as e.g. a sole foam is mixed with conventional plastic, the material is usually not biodegradable
    • Many argue that vegetable matter is being taken away from the food industry. However, this is a completely different discussion with many pros and cons

     

    Examples

    Veja Condor

    Veja itself describes the Condor as the first post-petroleum shoe. The outer shoe, lining and insole are primarily made from recycled PET. Synthetic plastics are mixed with vegetable components in the sole and other elements. The midsole now only contains approx. 60% classic EVA foam, the rest is made from sugar cane and banana oil. In the sole, 40% conventional latex is mixed with natural latex, etc.

    Our friend Michael Mankus is a very experienced ultra runner and also works with running shoes. He tested the Veja Condor over a few distances. His judgment is rather mediocre: “If you are used to light footwear when running, the shoe quickly becomes too heavy for you. It is in a league with older Brooks or Asics models and therefore cannot be directly compared with a modern running shoe. For beginners who run 2 x 5 kilometers a week, the shoe is absolutely okay. For runners with more mileage per week, this shoe is not the best choice from a purely functional point of view.

    The Runners World, however, describes the shoe as a descent shoe for distances up to half marathons.

    What is admirable, however, is that the Veja brand is actually not a manufacturer of performance shoes. Against the background, this shoe is a successful first serve and for hobby runners like many of us certainly a useful alternative. In addition, one can expect that Veja will not stop here, but will continue to work on the materials made from vegetable matter.

    At this moment it is still some miles away from being a true post-petroleum or organic running shoe. This shoe must not end up in the environment. The shoe weighs 311 grams and has a drop of approx. 10 mm (this describes the height difference of the sole from the back to the front). LINK

    veja condor running shoe

    Reebok Forever Floatride Grow

    The Forever Floatride Grow takes a similar approach to the Veja shoe, but with a different recipe in some cases. Castor oil in the midsole, algae-based insole, eucalyptus fiber in the upper and natural rubber in the lower sole. Reebok does not provide any details on the website regarding the exact material content, but does communicate that the shoe is made from 59% bio-based materials. As with Veja, the same applies here: the components are mixed with vegetable substances, the shoe is still not biodegradable or the like and should ideally be incinerated (burned) after its use. At 264 grams, the Reebok is almost 50 grams lighter than the Veja. LINK 

    reebok forever floatride grow sustainable running shoe


    Allbirds Tree Dasher

    Allbirds is also one of the newcomers to the running scene. The materials used are similar to those of Reebok and Veja, but again used differently. Castor seeds in the midsole, upper made of eucalyptus fiber, midsole made of a sugar cane EVA, natural rubber in the undersole and merino wool in the heel. With the Tree Dasher, the drop is a little flatter than with Veja or Reebok. Allbirds compensates for all CO2 emissions for the shoe and is very transparent here.

    Fabian Hörst, founder of Planetics (online retailer from Munich for sustainable sports fashion), has tested the shoe on his runs:

    “There is a lot of space in the front part of the shoe. I also noticed that the shoes were a tad heavier than my previous running shoes. Overall, the shoe makes a high-quality impression on me. The already expected comfort was confirmed while running. After the first few kilometers, however, the Dasher felt very clunky for me personally. Then there was the heat that developed inside the shoe. First I blamed the sunny and warm weather for this. However, my feeling was also confirmed during the other runs in rain. Conclusion: I personally feel more comfortable with other running shoes because of certain properties are important to me, e.g., a tight fit and a good indoor climate. However, the Dasher can be the ultimate running shoe for many, it is wonderfully processed. As with everything in life, tastes are different." LINK

    allbirds tree dasher eco minded running shoe

    Hylo

    Hylo is a quiet newcomer to the running shoe scene about whom little is known so far. A London based agency is behind the brand development, the shoes are made in Putian / China. The shoe uses different bio-based materials. A by-product from corn production is used to knit the upper, and corn starch and castor bean oil are also added to the midsole. The insole is made of algae material (Bloom, see icebug, Vivobarefoot, etc.) and organic cotton, as are the laces. The shoe is to be returned and the website says that the sole will be shredded and made into a new sole and the upper shoe will be composted. The shoe is with 215 g a real lightweight. What and who exactly is behind it is unfortunately not known. There is no About Us section or similar on the website, which would be very desirable and could give the great project more credibility and identity. LINK

    Hylo sustainable running shoes

     

    Vivobarefoot Primus Lite II (Bio)

    As the name suggests, this shoe is only intended for a specific target group: for barefoot runners. While the Primus Lite II is partly made from recycled PET, the Primus Lite II Bio uses organic plant material (30%). By-products from maize processing and plant fibers are used in the upper material. Natural rubber and algae material (Bloom, as with Icebug) are added to the sole. Still, this shoe is far away from being environmentally friendly. LINK

    Vivo Barefoot Prime Lite II

    Luna Running Sandals Origen 2.0

    Those who, as a barefoot contender or professional, want to have less material on their feet, the Origen 2.0 running sandals by Luna Sandals might be something for you. The “more environmentally friendly” character of this sandal results from the fact that the sole is made from an old car tire and, compared to conventional shoes, simply consists of little material :-) LINK

    Luna origen 2.0 running sandals

    Approach 4: Develop shoes made for true circularity - very promising: 2021 will be the test year for the big players

    Circular mechanisms

    Developing shoes in your own cycle is the next evolutionary stage in terms of sustainable running shoes. The idea is that the shoes are either made from one material (mono-material shoe) or from easily separable materials. The shoes are returned to the manufacturer after use and then processed into new shoes. In this area, three big players will be launched in the coming year 2021, which we would like to briefly introduce to you here.

    Benefits:

    • Materials remain in the cycle and, ideally, can be reused very often
    • Companies do not have to constantly buy new raw materials in large quantities, but build their own material flow that they can control themselves
    • Companies and customers can move closer together and learn better from each other (memberships, take-back mechanisms, etc.)
    • End customers no longer buy countless new running shoes just out of the mood to buy, as they may have signed a shoe membership with a manufacturer

    Disadvantages:

    • You can no longer just throw your shoes in the garbage can ;-)
    • If the components are not made from harmless materials, they will continue to produce harmful microplastic debris as you run

     

    Examples


    Adidas Futurecraft Loop

    An impressive concept. According to its own information, Adidas developed the Futurecraft Loop for 10 years. In several iterations, the shoes were tested with athletes and creative people. The entire shoe consists of a single material: TPU, which was otherwise usually only used for the sole material. The entire shoe should be returned to Adidas after its use, shredded, melted down and made into a new Futurecraft Loop. A completely closed cycle. The shoe is scheduled to be launched in spring / summer 2021. In terms of performance, we can certainly look forward to the usual boost quality (hopefully). LINK

    Adidas Futurecraft Loop Circular Running Shoe

     

    ON Cyclon

    The approach of the On Cyclon is identical. The entire shoe is made of one material. However, it is not a petroleum-based material as it seems, but made from castor oil. The rest works like with Adidas, the shoe is then shredded, melted down and made into a new shoe. In contrast to Adidas, On is already one step further with the business model. You can no longer buy the classic shoe. You pay 29 Euro a month and can then use it accordingly. After a certain period of time you can return it and you can get a new shoe if you wish. You can currently register for the shoe here

    ON Cyclon eco running shoe made for circularity

     

    Salomon Index 1.0

    The third in the group is Salomon. They have developed a lot of credibility in recent years, both with athletes and in the lifestyle segment. Of course, a progressive sustainable running shoe should not be missing here. And this one looks promising. The index 1.0 is expected to consist of 2 material components. The sole and the upper shoe are reprocessed separately after they have been returned to the customer. However, Salomon does not promise that this will necessarily turn into running shoes again. A part of the circulating material should e.g. go into the brand's ski boots. The only question is whether it will continue in the cycle afterwards or whether the end of recycling has been reached here. In any case, we can also be curious to see how the shoe and the return concept prove themselves. LINK

    Salomon Index 0.1 recycling running shoe 2021

    Conclusion

    The optimal solution

    The vision of the industry should be:

    • a running shoe made of regenerative materials (vegetable)
    • all substances used during the manufacturing process and in the final product are harmless to nature and humans (no harmful sole wear)
    • At the end of the life cycle, the material can be reprocessed into a shoe without any loss of quality
    • it should be made under socially friendly conditions
    • the energy going into it should be regenerative
    • material flows should be “distance optimized” to save emissions in transport
    • packaging should be as harmless and beneficial as the product itself


    However, since this is more of a wishful thinking at the present time, two seriously meaningful approaches emerge: Either the shoe and its materials function completely in their own cycle. Adidas and On seem to be furthest here at the moment. Or the shoe is completely biodegradable and harmless. Reebok and Veja are seemingly the pioneers here.

    Send a signal with your purchase

    It is completely understandable that many runners put themselves through all the approaches and marketing promises and feel overwhelmed. So you just buy. You can't blame anyone here. In all the discussions about sustainability, there is one thing we cannot expect: that we, consumers, solve problems by limiting ourselves. By this, products ultimately remain not environmentally friendly.

    As the end buyer, however, we have a voice with every purchase decision. So when more customers buy the products that have a sustainable intent, that message gets through to the companies. As a result, more investment will flow into the further development of these products. Incidentally, this is the case in all industries, including building houses, buying toothpaste or buying a car.

    The running shoe manufacturers all know that they have to do something and are now testing how their first approaches are received in the market. So let's value these approaches and send the right signals back with our next purchase of running shoes.

     

     

    Images sources:

    Atanas Dzhingarov (Unsplash)
    Noah Buscher Unsplash)
    Leonid Danilov (Unsplash)
    Blake Carpenter (Unsplash)
    Brian Yurasits (Unsplash)
    Josh Calabrese (Unsplash)
    Katherine Volkovski (Unsplash)
    Marjan Blan (Unsplash)
    Pixabay

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    Respective shoe brands