Michael Phelps' wingspan is 3 inches longer than his height

Michael Phelps stands 6 feet 4 inches tall (193 cm) but has a wingspan of 6 feet 7 inches (201 cm) — three inches beyond what human proportions would predict. He also produces only about half the lactic acid of a typical athlete at equivalent effort, and his size-16 feet act as natural flippers. Phelps won 23 Olympic gold medals across four Games — more than any athlete in history — but sports physiologists note that he was physiologically built for swimming in a way that is essentially unrepeatable. The NBC documentary 'What Makes Phelps Perfect?' catalogued these anatomical anomalies in detail.

Source: NBC Sports documentary; Sports Illustrated profile (2008)