A lightweight, breathable, translucent and high-strength upper formed from a half-gauge knit, at least in part from a high tenacity yarn and a fusible yarn, is described. The upper may include a knit heel structure. Methods of manufacture, including exposing the upper to steam while in a tensioned state to at least partially melt the fusible yarn to adjacent yarns is also described. Subsequent cooling of the fusible yarn retains the upper in a stretched condition.