Described are soles for a shoe having a region with a plurality of pellets, each pellet having a hollow core structure. The plurality of pellets are formed of a composite material comprising a base layer and an outer layer. The base layer is formed of a material having a first melting temperature, and the outer layer is formed of a material having a second melting temperature. The first melting temperature is greater than the second melting temperature, and the plurality of pellets are bonded through melting of the outer layers while the inner layers retain the hollow core structure without melting.