IAAF rules define walking as a progression of steps, so taken that unbroken contact with the ground is maintained. At each step, the advancing foot of the walker must contact with the ground before the rear foot leaves the ground. During the period of each step in which a foot is on the ground, the leg must be straightened (i.e. not bent at the knee) at least for one moment, and in particular the supporting leg must be straight in the vertically upright position. Three verbal cautions are given prior to disqualification.
These rules, cautions and disqualifications in race walking are a technical not a moral censure. The walker is not punished for cheating, however disqualification at Centre level enables walkers to work on their faults and avoid disqualification at championship level.