Variability of electromyographic patterns for level-surface walking through a range of self-selected speeds.

The surface electromyographic patterns of eight muscles and the foot-contact patterns exhibited by 25 normal persons between the ages of 20 and 40, were measured and studied. These persons were walking indoors on a level surface without shoes at several different self-selected walking speeds. The electromyographic patterns demonstrated a considerable amount of interindividual variability at each speed. There were definite trends in the number of individuals exhibiting each pattern type as walking speed increased. The foot-contact patterns showed a consistent sequencing of foot events at all speeds with the double-limb support stages and stance phase comprising a smaller percentage of the gait cycle as speed increased.