Racewalking ≈ Sissy-walk
Racewalking is different from power walk.
Power Walk, or speed walk, is walking fast. At least one foot must be in contact with the ground, because otherwise it's jogging/running. A very good exercise, alternative to jogging.
Racewalking has additional rule: when leg contact the ground, the knee must be straight. (otherwise, it became crouch-running, like ninja)
Walking in maximal speed while not running, isn't natural. If you look at the videos, those racewalkers all have this weird sissy-like hip swinging form.