An article of footwear may incorporate a chamber with an outer barrier and a tether element. The barrier may be formed from a polymer material that defines an interior cavity, and tether element may be located within the interior cavity and joined to opposite sides of the barrier. Upon pressurization of the chamber, the tether element may extend across the interior cavity and be placed in tension by the outward force of a pressurized fluid within the interior cavity. The tether element may have a variety of configurations. For example, the tether element may have a diagonal orientation, or different tether elements may have different lengths. A tether element may also have plates or tie pieces secured to opposite sides of the chamber, with one or more tethers extending between. Also, the tether element may include one of more sheets that extend across the interior cavity.