Wondering how Michael Phelps does what he does so well? Bob Costas narrates an interesting look into the physiology of the most decorated Olympian ever in this video. As you ponder how he might capture his eighth medal of this Olympics tonight, the piece provides a few answers (and some nice shots of Phelps).

Costas’ conclusion? A mix of “superior genetics and immense dedication.” Seventeen races, two miles of laps and eight days of competition. Simply amazing.