A bladder which is particularly useful for a sole assembly of a shoe is
formed of multiple layers of barrier film to provide multiple pressurized
layers of cushioning fluid or gas when the bladder is filled. A multiple
gas layer bladder enhances cushioning response by relying more on the
response characteristics of the gas and reducing the amount of foam and
the dependence on foam as a cushioning material. The internal film layers
provide a truss-like geometry in cross section and act as tensile members
to impart a generally smooth surface contour to the bladder. The bladder
is constructed to provide complex regionalized cushioning profiles which
are coupled to the anatomy of the foot and expected loads at known
points.