US Patent 7694438 Article of footwear having an adjustable ride

An article of footwear has an upper and a sole. The sole has an upper sole member, a lower sole member, and at least one inflatable bladder disposed between the upper sole member and the lower sole member. The at least one inflatable bladder has an inflated state and a deflated state. A distance between the upper sole member and the lower sole member is greater in the inflated state than the deflated state. Varying the inflation of the inflatable bladder varies the amount of cushioning in the sole and the thickness of the sole so that the shoe can serve as a multipurpose shoe for activities requiring different amounts of cushioning, such as a training shoe and a racing flat.