The 400m is generally considered to be a highly anaerobic race, but the findings of various researchers on the percentage contributions of anaerobic and aerobic energy mechanisms are not consistent. Drawing on a selection of publications, this article looks at how the energetic characteristics of the event are studied and explains the reasons behind the variation in findings. It considers 1) differences between men and women athletes, 2) differences between sprinter and endurance type athletes, 3) the influence of different methodologies and 4) differences caused by the performance level of the athletes studied. The authors find that performance capacity represents the most important quantitative factor for explaining the different percentages of intervention of the energy mechanisms. They also look at oxygen consumption and suggest an increase in pH level in the first 150-200m inhibits Type II muscle fibres from using the aerobic mechanism in the later stages of the race.
