How do companies design athletic shoes?

Running as a sport can be traced back to the ancient Greeks, who advocated a culture based on sound bodies and sound minds. During Greek athletic contests, runners competed barefoot and often naked. Later, the Romans mandated that their messengers wear thin-soled sandals. As shoemaking evolved through the centuries, leather became and remained the favored material because of its durability. However, the first references to shoes designed specifically for running don't appear until 1852, when historians noted a race in which runners wore shoes with spiked soles. In 1900, the first sneaker, or all-purpose athletic shoe, was designed. Made primarily of canvas, this sneaker featured a rubber rim made possible by Charles Goodyear's 1839 discovery of vulcanized rubber. Known about for 1,000 years, rubber was finally rendered commercially useful when Goodyear heated and combined it with sulphur, thereby preventing it from hardening and losing its elasticity. In athletic shoes, rubber helped to cushion the impact of running on hard surfaces. However, it did not last as a shoemaking material: it was not durable, and leather returned as the preferred material for running shoes. Yet leather wasn't the ideal fabric, either. In addition to being expensive, leather shoes caused chating, and runners had to purchase chamois liners to protect their feet. A Scotsman known as "Old Man" Richings provided some relief when he invented a customized shoe designed with a seamless toe box (a piece of material inserted between the toe cap and the shoe lining and treated with a hardening agent, the toe box protects the toes against rubbing).