A running shoe is a light-weight shoe specifically designed for use by runners.
It needs to have the right cushioning for your foot and heel to absorb the weight of your body.
Major Parts of a Running Shoe
A typical running shoe has three major parts:
- Midsole, and
- Upper sole
The Upper Sole
The upper sole mainly acts as a protective barrier from rocks, debris, and dirt. It requires a sole material that can endure rough terrain. The best material to be used on the upper sole is the synthetic leather as it is sturdy and durable. The upper sole also contains a mesh to ensure maximum breathability in the shoes and reflective material that acts as safety gear.
The midsole is the part between the upper and outsole. It mainly provides cushioning and rebound and ensures mostly that your foot doesn’t feel any sharp or hard objects on the surface. They are three different types of materials that can be used to make the midsole; EVA, dual EVA, and polyurethane.
The outsole is used for traction and contains flex grooves for maximum flexibility. It is commonly made of two materials the carbon rubber and blown rubber.
Related Read: Best Running Shoes in India
Two Types of Soles for Running Shoes
It is correct to state that the sole of the running shoe is mainly made of two materials the EVA and rubber.
The two elements have their pros and cons. However, depending on the use of the jogging shoes it is possible to identify which content is better than the other.
Rubber is mainly found into two forms the natural rubber and synthetic rubber.
Both are used to make the sole of jogging shoes, but their qualities differ.
Natural Rubber Soles
Natural rubber is also known as caoutchouc or india rubber.
It is made up of polymers from the isoprene compound but also has impurities found in some organic compounds and water. The natural rubber is very soft and elastic.
Its properties make it very suitable for making high-quality running shoes.
However, it is not water-resistant and thus not durable. It can only be used to make the soles of indoor jogging shoes.
Synthetic Rubber Sole
Synthetic rubber is any synthetic elastomer that is mainly derived from synthesized petroleum products.
It is a human-made type of rubber and can be found in different forms.
- Water-resistant rubber: It is durable due to its robust properties, and it is resistant to abrasion. It is mainly used to make jogging shoes that are used in rugged terrain.
- Sticky rubber: It is very flexible and can prevent any slipping. It is mostly used to make soles of jogging shoes used for indoor activities.
- Environmental rubber: it is formed from recyclable materials and is durable.
- Air rubber: It has absorption properties. However, the sole material is not durable and as it will break down after some time of wearing it.
- Hard rubber: It is very hard and has water-resistant properties and can be used to make jogging shoes for use in rough surfaces.
- Carbon rubber: It is one of the most durable types of synthetic rubbers. It is used to make the outsole of jogging shoes as it is resistant to wear and tear.
- Blown rubber: It is not durable, but it is highly flexible, cushioned and light in weight.
Pros and Cons of using rubber for making running shoe soles.
Ethylene Vinyl Acetate(EVA) Sole
Ethylene Vinyl Acetate (EVA) is made from two compounds – vinyl acetate and ethylene.
It is also referred to as polyethylene-vinyl acetate, a compound known as a copolymer of vinyl acetate and ethylene.
EVA is now the most widely used midsole material for shoes.
It almost resembles the rubber material but it is more flexible and soft can mostly be used to make the midsoles of the jogging shoes.
EVA material is elementary to processing as you can compress it into many forms.
It can take different types of colors, and its properties can resist UV radiation. It can also resist cracking due to the weight of the feet. It can also be used to make sole liners, outsoles, and some manufacturers use it to make the entire shoe.
EVA contains a weight of 10 to 40% of vinyl acetate with the rest of the weight being made of ethylene.
There are three types of EVA and are mainly classified according to the content of vinyl acetate used in the compound. However, if the weight of the vinyl acetate is low, the material is lighter and less durable.
- Polyethylene modified with vinyl acetate: It has a low percent of vinyl acetate(average of 4%). It is processed like most thermoplastic materials and is mainly a non-toxic material.
- Thermoplastic ethylene: It contains around 4 to 30% of vinyl acetate and resembles mostly the features of rubber.
- Ethylene vinyl acetate: Includes more than 40% of vinyl acetate in the compound and is more substantial than the other two.
EVA that contains a higher percentage of vinyl acetate almost resembles rubber in its properties.
Pros and cons of using EVA for soles in running shoes
Conclusion – Which type of soles in best for running shoes?
The two materials are useful in running shoes.
However their adaptability differs depending on the surfaces you are running on, the speed you intend to achieve and the distance you want to cover.
If you are running for long distances and at a faster speed select soles made of EVA as they light-weight.
On the other hand, rubber soles are heavy and can be able to sustain rough surfaces.
Additionally, if you are making your purchasing decision depending on the durability buy running shoes with soles made of rubber.
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