Abstract: A footwear construction including a sole assembly, which can include a midsole including a midsole support wall forming a compartment and a compression molded core constructed from thermoplastic polyester elastomer (TPEE) disposed in the compartment and shielded from abrasion in the environment of the footwear in use via the midsole support wall. The core can be formed by compressing a foam core to increase its density, for example, from a first density between 0.05 g/cm3 and 0.08 g/cm3, inclusive, to a second density between about 0.09 g/cm3 and 0.12 g/cm3, inclusive. Such compression molding and the attendant density increase of the TPEE core can increase energy efficiency to at least 95% energy efficiency, when the midsole is installed in footwear. A related method of manufacture is provided.