Racewalking is a long-istance event in the sport of athletics. Although the idea is to get from point 'A' to point 'B' as quickly as possible on two legs, racewalking is biomechanically quite different from running. According to the rules (below) 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 distances are 20 kilometers (12.4 miles) and 50 kilometers (31 miles.)