What is Racewalking?

According to Section V of the USATF Rule Book (1996), racewalking is as follows:

"Racewalking is a progression of steps so taken that the walker makes contact with the ground so that no visible (to the human eye) loss of contact occurs. The advancing leg must be straightened (i.e., not bent at the knee) from the moment of first contact with the ground until in the vertical position."