Fibres used for running gear - an overview
Running has turned to become a trendy sport. It moves the masses. That's awesome.
With the growth of the running community, the sports gear industry has also been growing. That's also awesome. It has become really innovative to find solutions for the runners needs and has helped taken the sport to new levels.
For every different use case you will find a running shirt that solves a multitude of different problems.
There are dozens of solutions out there to make you a better runner in the form of clothing.
As written in our other blog post, plastic already has a long history in sports gear. It is highly dominant. Over the past few years, more natural and chemical fibres have made their way (back) into the sport.
Before we jump in to compare different fibres that can be used for running gear, let's quickly check, what's important for a runner.
Performance criteria for your gear
Temperature: of course, when you are out running, the perfect running gear should keep your body warm when it's cold and cool when it's warm. Sounds like a simple process but it’s one of the trickiest parts to solve using textiles.
Moisture management: The second trickiest part. The ideal fibre should absorb the sweat from your body and then release it to the outside (“wicking”). If you are wearing many layers, it is important that every layer is able to work with the layer below or under it. Otherwise, most technical moisture management solutions can’t work. To give you an example: if you are wearing your cotton underwear and then put a technical Polyester fibre above it, the Polyester can’t do its job of bringing the moisture to the outside as the cotton is keeping it inside.
Weight: When out running you want to make sure that you are not carrying more weight with you as necessary. Sometimes it's funny to see people spending hundreds of bucks for their special lightweight gear and then carrying water and a smartphone with them, which together will probably have 3 times the weight of their outfit. Certain fabrics can weigh more than others when you sweat in them or get wet.
Movability: The gear should move with you and not hinder you in any way. It needs to allow for the movements you are making during your workout. In running this is straightforward, the pants need to allow for sufficient freedom in the hips and legs. Your torso won't happen that much (of course, depending on your running style).
Comfort: You should feel good in your gear. “Feeling good” is a highly subjective thing. Most people consider this criteria on a physical dimension, this means the fabrics should feel good on the skin and it should be “healthy”, this means the fabric should not do any harm to the human body (chemicals etc.). However, more and more people want to have a good conscience when jumping in their outfit. They at least don’t want to do anything harmful to the planet.
Now that we are on the same page, let's talk about the different fibres that can be used to make running gear.
3 different families of fibres
In general, we could differentiate between fully synthetic, semi-synthetic, and natural fibres.
Fully synthetic fibres are those made of non-regenerative raw materials (typically crude oil) combined with many different chemicals (that list can go on for days). The typical fibres you will find are Polyester, Polyamide (aka Nylon), and Polypropylene.
Semi-synthetic or chemical fibres have typically a regenerative raw material as foundation (typically any type of wood) and are then treated with chemicals to make a fibre out of it. The most famous one is viscose. There are many different manufacturing processes that exist for cellulose based viscose. Currently, the most famous type of cellulosic based fibre is called Tencel Lyocell.
Natural fibres come as they are from certain plants or animals. To make a textile fibre out of it is often treated in a certain way. Examples are cotton, wool, linen, hemp, or silk.
Let's discuss some of them in a bit more detail and start with the full synthetics.
Nylon (Polyamide) will be found often in leggings or biking gear. It is probably the most durable and robust synthetic fabric. Also, it is stretchy and highly non-abrasive.
Polyester and Polypropylene are also very often used. Polyester can be found in almost all technical textiles. They are very fast when it comes to moisture wicking as they are simply not absorbing any sweat and move sweat away very quickly.
Let's summarize some pros and cons of those synthetic fibres as they are quite similar to each other:
- Fast Drying
- Keep its Form
- Doesn’t Wrinkle
- Non-Moisture Absorbing
- May Keep Heat Inside
- No Antibacterial Processing
- Skin Irritation Possible (as sweat is not absorbed)
- Environmentally harmful as it is not regenerative, not biodegradable, theoretically recyclable but in practice not applied (in 2017 in Germany only 1% of Polypropylene was recycled, most of it from food packaging)
Merino: Merino wool has gained importance in the outdoor and sports industry. It is very soft and doesn't smell bad as fast as many synthetics. Also, it has isolating effects due to air kept in the fibres (cools when warm outside, warms when cool outside). It absorbs and wicks moisture very well and is fast drying. Seems like the perfect fibre right? However, when Merino wool is used it is important to use wool which comes from tracked origins which treat their animals well (look for non-mulesing wool).
Hemp: from a pure environmental perspective, this plant would make the first place in any fibre comparison. Hemp grows everywhere, is great for the soil, doesn ́t need much water, grows fast, etc. It is also very skin friendly and extremely solid / robust. Hemp absorbs moisture (sweat) similarly well as cotton does, but releases it a bit faster than cotton (but still not very fast). For certain use cases, hemp can be a fantastic counterpart. We are sure it will play a more important role in the future of any type of fashion – hopefully also in sports gear.
Cotton: the fabric made for the warriors among us runners. When living in the UK I met many high performing runners who still run in nothing else but their cotton shirts (often tank-top style). Cotton absorbs much moisture but it also keeps it. This means you are carrying it with you. Combined with wind this may let you feel cold. However, if you don’t have issues with chaffing and cold breezes, this fabric will be your hero. Running 20k plus in cotton socks will give you blisters and wearing a heavily soaked cotton shirt for this run will make your nipples schaf… eek. As I am not such a heavy sweater, I am often running in cotton shirts for distances up to 12 km.
- Natural fabrics can absorb moisture from the body, which synthetics can’t do so easily
- They are from regenerative sources, be it plants or re-growing wool
- Plant based fabrics are typically very robust. I am wearing the army cotton shirts of my dad, those are 40 years old and they still have a high quality – amazing.
- Natural fabrics typically don’t show the odor problems you will have with plastic based fabrics which means you won’t stink after sweating like hell!. This means, you don’t have to wash them that often.
- They are biodegradable.
- Except for merino wool, natural fibres typically don´t show a good wicking performance, this means they keep the moisture inside
- Some fabrics are not as robust as synthetic ones. Wool for example needs to be treated with more care than other fabrics (for example you should not put them into the washing machine with zippers or other metals)
- Depending on the material they may need much water to produce or grow them (cotton for example)
- Vegans argue that wool is not a good choice as animals aren't treated well. Farmers argue against that sheep can't live without being shorn as insects would nest inside their hair. Also, if it would be more attractive for farmers to hold sheep because of their wool and not their flesh it could have a great twist in focus. Marine biologists argue that the microplastic washed off from synthetic textiles in the end has a larger damage on animal live then shearing sheep.
Tencel Lyocell: this is a cellulose based fibre made of wood (Eucalyptus). It has a certain strength, is known for its extreme softness and has some similarities in the structure with merino wool, which allows absorption and release of moisture (not as fast as Merino) and to cool the body when it's warm. It is made with a sustainable production process (less harmful chemicals and closed loop, i.e. chemicals are staying in the production loop) and is plant based (Eucalyptus). The fibre is exclusively made by the company Lenzing from Austria (Link).
Bamboo: as it is also a viscose, the benefits are similar to Tencel. Bamboo as source for this type of viscose is fantastic, as it is a plant which grows extremely fast (faster than any other biomass used for the production of viscose). However, when using bamboo viscose it is important, that the manufacturer has a bulletproof water recycling process as otherwise harmful chemicals could enter the water ecosystem (you need other chemicals than for Tencel Lyocell).
As you can see, there are many options out there and all of them have their pros and cons. It really just comes down to the consumer to decide what is most important for them. From an environmental perspective, the non-synthetic fibres are leading. From a purely performance perspective, synthetics have a lot of benefits. Some natural and semi-synthetics are very strong competitors in the performance realm. We see the environmental downsides of plastic fibres (microplastic waste) as harmful and think that these can be easily avoided. Certainly there may be trade-offs - as with everything when it comes to consumption or life. The most important thing is that you feel good with no matter what you are deciding for and more important that you enjoy your run to the fullest. Keep running friends!
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