The performance of two Olympic race walkers was studied during free-speed, fast, and race walking. Measurements of the stride and temporal components of gait, as well as the simultaneous displacement patterns of the body segments, and the electromyographic activity of muscles of the trunk and upper and lower limbs were recorded during the three walking speeds. During the testing, the race walkers achieved an average speed of 12.5 km/hr as compared to the 8.7 km/hr average speed achieved by normal men of the same age during fast walking. Race walking was characterized by an increase in cadence and stride length beyond that of normal controls (in a prior study) during fast walking, with stride lengths averaging 125% of stature during race walking, and 115% during normal fast walking. In the two race walkers the amplitudes of most of the movement patterns of the trunk and upper and lower limbs were exaggerated during race walking as compared to normal controls' fast walking. Several mechanisms were used by the race walkers to minimize the vertical excursion of the center of gravity of the body during race walking. All of the muscles monitored in the race walkers showed an increase in the amplitude of electromyographic activity during race walking as compared to fast walking; duration of muscle activity was also usually increased during race walking. Several suggestions for prevention of injuries associated with race walking are made.