EVERYDAY MATERIALSAtlas
Clothing & movement / object study

Running shoe

A hard-wearing surface, a soft middle, a flexible shell.

AI-generated representative illustration: sage and sand running shoe with a mesh upper.
AI-generated representative studio illustration. Construction varies by product.
A familiar object, opened up

A running shoe combines materials that behave very differently under load. The upper holds and ventilates the foot. A foam midsole compresses and recovers, while a tougher outsole faces repeated contact with the ground. Laces, seams, adhesives and lining complete the assembly. This example uses an EVA-based midsole and textile upper; many contemporary shoes use other foam formulations, so it should not be read as a particular model’s construction.

4 assemblies6 linked materials
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Inside the object

OBJECT 08 / COMPONENT INDEXSELECT A NUMBER ↗
Explore the components of Running shoeConceptual illustration, not to scale. The numbered component index is adjacent; markers are navigation points, not exact disassembly locations.1234

Original conceptual illustration. Numbers open the component index; their positions are illustrative, not a disassembly guide. Equivalent text follows beside the diagram.

1Textile upper

Polyester or nylon yarns can be knitted or woven into an upper with selected stretch and ventilation. Reinforced areas help secure the foot while more open areas allow airflow. Fibre choice matters, but the textile pattern, coatings and seam placement also determine how the upper behaves.

Polyester fibre Nylon

2Foam midsole

EVA can be expanded into a cellular foam that compresses under load and recovers after release. The gas-filled structure gives cushioning at a lower mass than a solid polymer block. Foam density, cell structure and formulation influence feel and ageing; the name EVA does not specify a single performance level.

EVA

3Outsole

Rubber compounds provide the ground-contact surface, often with reinforcing fillers such as silica or carbon black. Natural rubber may be blended with synthetic rubbers. Tread shape and compound formulation affect grip and wear together, so the outsole is not simply a sheet of unmodified tree latex.

Natural rubber Silica

4Sockliner, seams and bonds

A removable foam sockliner can cushion and shape the interior. Polyester thread joins textile regions, while adhesives bond many soles to uppers. Polyurethane is one possible foam or adhesive family. These interfaces make a flexible assembly practical but complicate clean separation of material fractions later.

Polyurethane Polyester fibre
Designed differences

Why these materials?

Each step asks different parts of a shoe to do different things. An outsole that wore like a soft midsole would fail quickly; an upper made as rigid as the outsole would fit poorly. Cellular foam changes the response of the underlying polymer by introducing empty space. The result is a composite object even when it contains no carbon-fibre plate. Its performance depends on geometry, fit and the complete construction, rather than one ingredient. Bonding improves manufacturing and load transfer while making component replacement and material sorting more difficult.

One object, many versions.

Foams may use polyurethane, expanded thermoplastic polyurethane, polyether block amide or proprietary blends rather than EVA. Some shoes include carbon-fibre composite or polymer plates. Trail outsoles, track spikes and minimalist shoes have different priorities. Material names do not determine which shoe is suitable for a particular runner, and this overview does not imply an injury-prevention or performance guarantee.

What happens after use?

Keep usable shoes in circulation when they remain fit for their intended purpose. Repairability depends on the construction and available repair services; a worn outsole does not always mean an upper can be economically recovered. Specialist footwear take-back programmes may separate or shred materials, but are not available everywhere. Shoes should not be placed into ordinary plastic packaging collection simply because most components are polymers.

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Follow the evidence

Original explanations informed by the sources below. Technical and industry sources support material behaviour; industry environmental marketing is not treated as a universal comparison. Browse the source register.