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!