What was unusual about Olympic gold medalist William Paul Dickey's type of dive at the 1904 St Louis games?

At the 1904 Olympic Games in St. Louis, USA, plunging was on the program, which made sense back then because this sport peaked in popularity in the late 19th century. For the record, William Paul Dickey of USA won the contest with a jump measured at 62 feet and six inches (19.05 metres). All four other competitors were also from the USA.

According to the 1920 "Official Swimming Guide" of the American Swimming Association, the plunge for distance "is a dive from a stationary take-off which is free from spring from a height of 18 inches above the water. Upon reaching the water the plunger glides face downward for a period of 60 seconds without imparting any propulsion to the body from the arms and legs." To determine the total distance traveled, the measurement was taken from the farthest part of the body from the start, "opposite a point at right angles to the base line."