We all know that running shoes are different from any other casual shoes as these shoes are specially designed for the activity of hitting the road. Over the years, there has been a drastic change in demand for running shoes and the primary reason is that more and more people are starting to run, and marathons have become a weekly affair. And with the increase in demand, there have been a whole lot more shoe makers in the market.
While big brands such as Adidas, Asics, New Balance, Reebok, Nike and Saucony still rule the roost, smaller brands are starting to add new features to their shoes in order to gain eyeballs. However, the fact remains that the basic parts of a running shoe remain the same, with proprietary tech added to boost the feature set. So here’s what goes into the making of a running shoe.
The outsole or sole of the shoe is the bottom part of the shoe. Depending on the type of material used, the outsole defines what kind of a ride you will get when running. Manufacturers use one of two materials or a combination of both to make soles. Carbon rubber is a durable material that is used in the majority of running shoe outsoles. You will find carbon rubber soles in rigid shoes such as those meant for trail running. These provide greater stability when running. Blown rubber, which is air-injected is much lighter, softer and more flexible, and hence is more likely to be used in minimalist shoes. When being used in a combination, blown rubber is often found in the forefoot area, which needs slightly less rigid structure.
The midsole is the most complex part of the shoe and often you will find a mix of different kinds of plastics used to offer support. This is the spongy material between the outsole and the upper that provides the extra cushioning, or springiness when running. Nowadays, you will find a proprietary tech in the midsole that makes use of a combination of materials. Traditionally, ethylene vinyl acetate or EVA, a plastic-based material, is used. Polyurethane is also used when the need is for a heavier material. Shoes with enhanced stability and over-pronation support feature Dual-Density materials.
Between the outsole and the insole is the shank, which adds to the support structure of the shoe. It reduces the load on the runner’s feet and calves when the terrain is uphill. It’s made out of a range of materials such as rigid plastic, fibreglass and kevlar. It serves to protect the feet from puncture wounds or sharp objects on the track.
As the name says, the upper is the part that wraps around your foot, defining the outline of the shoe. It is made of overlays or synthetic materials that criss-cross the upper part and provide support and reinforcement. The use of materials in the toe-box or front portion of the upper defines how much room runners have to for their foot to expand. These days uppers are made out of a combination of materials ranging from mesh to rubber, depending on the purpose of the shoe. Minimalist shoes tend to have a breathable mesh upper for better air conditioning for your feet. This is the most popular material you will find in most running shoes these days.
‘Lasts’ is the manner in which the upper part of the shoe is attached to the midsole. Its construction defines how much flexibility the shoe offers. Board lasted shoes have a firm board that provides a rigid platform for the foot. These are the most stable but are less common nowadays as runners tend to go for more flexible shoes. Slip Lasted means the upper is wrapped under the foot without using any type of board, resulting in less rigidity and greater flexibility. These are becoming more and more common these days. Manufacturers also use a combination for the last, which offers stability and flexibility, for the best of both worlds. And finally, there are Strobel lasted shoes, which also perform just like combination lasted shoes. This involves a thin layer of plastic-based material glued firmly to the midsole, upon which the upper is stitched. These have become the most common type of lasts in running shoes.
A seemingly minor part of the shoe, but it defines your foot comfort and consequently your strides and cadence. It’s basically a removable insert that you place over the insole of the shoe, that helps you get a better fit. It also prevents chafing of the shoe and are recommended for those using orthotics to run.
This is a small plastic insert used to reinforce the heel cup of a shoe and increase support. Essentially, it’s the slight raised part of the shoe behind your ankle, that cradles the heel and arch. A good firm heel counter offers greater support for those with foot, ankle and knee problems. Shoes with flexible heel counters are best for training and are advised for experienced runners. Try flexing the heel counter to understand which shoe is best for your needs.
An additional layer of material and light cushioning in the entry point of your shoe prevents the foot from slipping and gives your proper grip when you are running.