Method of manufacturing a tunable midsole for an article of footwear

A method of making a midsole, comprising the steps of:

• selecting a plurality of yarns, wherein at least two yarns of the plurality of yarns have different properties relative to one another;
• bundling the plurality of yarns to form a bundled yarn structure;
• intertwining the bundled yarn structure to form a twisted yarn structure, the intertwining comprising the steps of:
• fixing an end of the bundled yarn structure;
• applying axial tension to the bundled yarn structure;
• and
• rotating the bundled yarn structure to form the twisted yarn structure;
• depositing the twisted yarn structure into a first mold within an autoclave;
• applying a supercritical fluid to the twisted yarn structure, wherein the supercritical fluid infiltrates and saturates the twisted yarn structure;
• depressurizing the autoclave to cause a foaming process therein to convert the twisted yarn structure into an anisotropic foam blank;
• and
• depositing the anisotropic foam blank within a second mold that is configured as a midsole for an article of footwear.