Racewalking, or race walking, is a long-distance athletic event. Although it is a foot race, it is different from running in that one foot must appear to be in contact with the ground at all times. Stride length is reduced, so to achieve competitive speeds, racewalkers must attain cadence rates comparable to those achieved by Olympic 400-meter runners—and they must do so for hours at a time since the Olympic events are the 20 kilometer race walk and 50-kilometer (31 mi) race walk.