Article of footwear having an elevated plate sole structure

An article of footwear having an upper and a sole structure secured to the upper, the sole structure comprising:

• a midsole formed from a foamed polymer material and positioned adjacent to the upper;
• a first columnar impact-attenuating member located in a heel portion of the sole structure in a substantially upright configuration oriented toward the upper;
• a second columnar impact-attenuating member located in a heel portion of the sole structure in a substantially upright configuration oriented toward the upper;
• an elevated plate structure formed from a substantially non-foamed material and being substantially embedded within the midsole, the elevated plate structure comprising:
• an upper plate having an upper surface oriented toward the upper and an opposite lower surface oriented away from the upper;
• a first leg extending downward from the lower surface away from the upper, a lower portion of the first leg forming a portion of the first columnar impact-attenuating member;
• a second leg extending downward from the lower surface away from the upper, a lower portion of the second leg forming a portion of the second columnar impact-attenuating member;
• and
• a lower plate oriented generally parallel with the upper plate and configured to provide a support for receiving downward impacts transmitted through the first and second columnar impact-attenuating members during use;
• an outsole at a bottom portion of the article of footwear opposite the upper configured to engage a ground during use;
• wherein the first and second leg each forms a hollow container extending downward away from the upper, the hollow container having an opening at its distal end and forming a gap between the distal end and the lower plate when the article of footwear is in a relaxed state without receiving downward impacts;
• and
• wherein the first and second columnar impact-attenuating members each further comprise a compressible plug disposed partially within the hollow container, extending through the distal end opening, disposed partially within the gap between the distal end and the lower plate, and having a free distal end spaced apart from the lower plate in the relaxed state;
• wherein the compressible plug is resilient and is slidably disposed within the hollow container, and
• wherein the free distal end of the compressible plug is sized larger than the distal end opening of the hollow container such that the compressible plug is increasingly compressed as the compressible plug is moved upward into the distal end opening of the hollow container.