New sneaker technologies increase performance. Nike’s Air Force used little pockets of gas to create better cushioning, while Reebok introduced The Pump—air pumped into shoes to make them fit more snugly. Sneaker surprises continue: Spira Footwear, for example, has built a spring in the soles to reduce foot stress. Of course, innovations like these come with a price: Athletic shoes often cost more than $100 a pair!