Whether you’re sprinting 100 meters or pacing a 5K, the track itself is working with your body. Let’s dig into what makes a good track, and how materials science makes it possible.
A Brief History of Track Surfaces
Running tracks weren’t always smooth. Back in the day, athletes ran on cinder tracks (crushed rock and ash). They were soft but unpredictable; puddles in the rain, dust in the wind, and uneven ground could slow athletes down or cause injury. Then came the 1968 Olympics in Mexico City — and the first synthetic track. The beginning of a new era of track and field.
What Are Modern Tracks Made Of?
Most modern tracks today are made of polyurethane-based rubber compounds. Here’s a breakdown of the layers:
Layer One: Asphalt
The bottom layer of running tracks is made from asphalt, a derivative of crude oil refineries. Crushed stones like gravel, sand, and other tiny rocks are glued together using bitumen, a waste product of refined oil. This layer provides a stable base and allows water to seep into the ground more quickly after rain.
Layer Two: Binder
The middle layer is used as a connector between the two layers. Small rubber granules are mixed with a polyurethane binder solution to create a sticky layer to add the top onto. Interestingly, the polyurethane binder is made on-site because it would stick to any container it’s in. Polyurethane is created using Isocyanate and Polyol in a polymerization reaction, where many polyurethane monomers, each created using one isocyanate and one polyol, combine to create long chains of polyurethane.
Layer Three: Surface
Made from rubber granules and even more polyurethane, the top layer is the softest to make sure you don’t injure yourself. In the polyurethane binder, a rubber called EPDM is what gives tracks their bouncy feel and red color. Because of its weaker intermolecular forces, EPDM is the most elastic part of a track, making it perfect for softening impacts while retaining most of the energy. EPDM is made by vulcanizing two common gases: ethene and propene.
What Makes a Track Fast?
The attributes of a track that make it fast can be broken down into two sections: energy return and friction. Imagine bouncing a tennis ball on concrete vs. on a pillow. On the concrete, it rebounds. On the pillow, it softly comes to a halt. While concrete returns most of the energy, it can damage whatever lands on it, for example, your feet. Polyurethane tracks strike the perfect balance of a strong and stable base while maintaining soft enough rubber to keep you safe.
Friction is necessary to go anywhere quickly; imagine trying to start a car on snow. The track’s surface is slightly rough and often embedded with tiny rubber granules or spikes to increase grip — like a built-in sandpaper layer, but safe for skin and shoes.
In Conclusion
So next time you line up at the start line, remember: the track beneath you isn’t just a slab of rubber. It’s a carefully engineered surface made to propel you forward, protect your body, and stand up to time — all thanks to materials science.
From recycled tires to Olympic medals, it’s science under your soles.