An article of footwear (10, 10a) comprising: an upper; an outsole (210, 210a) attached to the upper and including a ground-engaging surface and an inner surface (214, 214a) disposed on an opposite side of the outsole (210, 210a) than the ground-engaging surface; a midsole (220, 220a) having a footbed and a bottom surface (222, 222a) disposed on an opposite side of the midsole (220, 220a) than the footbed and opposing the inner surface (214, 214a) of the outsole (210, 210a) to define a cavity (240, 240a) therebetween; a first series of projections (300, 310, 300a, 310a) disposed proximate to a heel portion of the article of footwear (10, 10a) and extending into the cavity (240, 240a) from one of the inner surface (214, 214a) and the bottom surface (222, 222a) in a first direction toward the other of the inner surface (214, 214a) and the bottom surface (222, 222a), the first series of projections (300, 310, 300a, 310a) being spaced apart from the other of the inner surface (214, 214a) and the bottom surface (222, 222a); a second series of projections (300, 320, 300a, 320a) disposed proximate to a forefoot portion of the article of footwear (10, 10a) and extending into the cavity (240, 240a) from the one of the inner surface (214, 214a) and the bottom surface (222, 222a) in the first direction toward the other of the inner surface (214, 214a) and the bottom surface (222, 222a), the second series of projections (300, 320, 300a, 320a) having a different height than the first series of projections (300, 310, 300a, 310a) and being spaced apart from the other of the inner surface (214, 214a) and the bottom surface (222, 222a), the first series of projections (300, 310, 300a, 310a) extending farther from the one of the inner surface (214, 214a) and the bottom surface (222, 222a) than the second series of projections (300, 320, 300a, 320a); and a quantity of particulate matter including foam beads disposed within the cavity (240, 240a). an upper; an outsole (210, 210a) attached to the upper and including a ground-engaging surface and an inner surface (214, 214a) disposed on an opposite side of the outsole (210, 210a) than the ground-engaging surface; a midsole (220, 220a) having a footbed and a bottom surface (222, 222a) disposed on an opposite side of the midsole (220, 220a) than the footbed and opposing the inner surface (214, 214a) of the outsole (210, 210a) to define a cavity (240, 240a) therebetween; a first series of projections (300, 310, 300a, 310a) disposed proximate to a heel portion of the article of footwear (10, 10a) and extending into the cavity (240, 240a) from one of the inner surface (214, 214a) and the bottom surface (222, 222a) in a first direction toward the other of the inner surface (214, 214a) and the bottom surface (222, 222a), the first series of projections (300, 310, 300a, 310a) being spaced apart from the other of the inner surface (214, 214a) and the bottom surface (222, 222a); a second series of projections (300, 320, 300a, 320a) disposed proximate to a forefoot portion of the article of footwear (10, 10a) and extending into the cavity (240, 240a) from the one of the inner surface (214, 214a) and the bottom surface (222, 222a) in the first direction toward the other of the inner surface (214, 214a) and the bottom surface (222, 222a), the second series of projections (300, 320, 300a, 320a) having a different height than the first series of projections (300, 310, 300a, 310a) and being spaced apart from the other of the inner surface (214, 214a) and the bottom surface (222, 222a), the first series of projections (300, 310, 300a, 310a) extending farther from the one of the inner surface (214, 214a) and the bottom surface (222, 222a) than the second series of projections (300, 320, 300a, 320a); and a quantity of particulate matter including foam beads disposed within the cavity (240, 240a).