A method for making a foamed article (265; 319), the method comprising: placing an article (214; 216; 218) and carbon dioxide (240; 246; 604; 614) in a vessel (234; 480; 602), wherein the article (214; 216; 218) comprises a foamable fibrous element including a first plurality of filaments, fibers, yarns, or any combination thereof, the first plurality of filaments, fibers, yarns, or any combination thereof comprising a solid foamable material (210; 502; 620a; 620b) which is a thermoplastic elastomeric material comprising one or more first thermoplastic elastomers; after the placing, maintaining the vessel (234; 480; 602) at a first pressure and first temperature, wherein the first pressure and first temperature are a pressure and temperature at which the carbon dioxide (240; 246; 604; 614) is a liquid and the liquid carbon dioxide (240; 246; 604; 614) is soluble in the solid foamable material (210; 502; 620a; 620b), and wherein the maintaining includes holding the article (214; 216; 218) and the liquid carbon dioxide (240; 246; 604; 614) in the vessel (234; 480; 602) for a duration of time sufficient for at least a portion of the liquid carbon dioxide (240; 246; 604; 614) to infuse into the solid foamable material (210; 502; 620a; 620b) of the foamable fibrous element, thereby forming an infused article (255; 256); following the maintaining and holding, optionally exposing the infused article (255; 256) to a second pressure and second temperature at which the carbon dioxide (240; 246; 604; 614) remains infused within at least a portion of the solid foamable material (210; 502; 620a; 620b) of the foamable fibrous element; following the maintaining and holding and the optional exposing, subjecting the infused article (255; 256) to a third pressure and third temperature at which the carbon dioxide (240; 246; 604; 614) infused in the solid foamable material (210; 502; 620a; 620b) of the foamable fibrous element phase transitions to a gas, thereby expanding the solid foamable material (210; 502; 620a; 620b) of the foamable fibrous element into a foamed material (506; 620c) and forming the foamed article (265; 319) including a foamed foamable fibrous element; and wherein the solid foamable material (210; 502; 620a; 620b) has a Shore A hardness of from 35 A to 95 A. placing an article (214; 216; 218) and carbon dioxide (240; 246; 604; 614) in a vessel (234; 480; 602), wherein the article (214; 216; 218) comprises a foamable fibrous element including a first plurality of filaments, fibers, yarns, or any combination thereof, the first plurality of filaments, fibers, yarns, or any combination thereof comprising a solid foamable material (210; 502; 620a; 620b) which is a thermoplastic elastomeric material comprising one or more first thermoplastic elastomers; after the placing, maintaining the vessel (234; 480; 602) at a first pressure and first temperature, wherein the first pressure and first temperature are a pressure and temperature at which the carbon dioxide (240; 246; 604; 614) is a liquid and the liquid carbon dioxide (240; 246; 604; 614) is soluble in the solid foamable material (210; 502; 620a; 620b), and wherein the maintaining includes holding the article (214; 216; 218) and the liquid carbon dioxide (240; 246; 604; 614) in the vessel (234; 480; 602) for a duration of time sufficient for at least a portion of the liquid carbon dioxide (240; 246; 604; 614) to infuse into the solid foamable material (210; 502; 620a; 620b) of the foamable fibrous element, thereby forming an infused article (255; 256); following the maintaining and holding, optionally exposing the infused article (255; 256) to a second pressure and second temperature at which the carbon dioxide (240; 246; 604; 614) remains infused within at least a portion of the solid foamable material (210; 502; 620a; 620b) of the foamable fibrous element; following the maintaining and holding and the optional exposing, subjecting the infused article (255; 256) to a third pressure and third temperature at which the carbon dioxide (240; 246; 604; 614) infused in the solid foamable material (210; 502; 620a; 620b) of the foamable fibrous element phase transitions to a gas, thereby expanding the solid foamable material (210; 502; 620a; 620b) of the foamable fibrous element into a foamed material (506; 620c) and forming the foamed article (265; 319) including a foamed foamable fibrous element; and wherein the solid foamable material (210; 502; 620a; 620b) has a Shore A hardness of from 35 A to 95 A.