This document defines aerobic capacity and VO2 max as the maximum amount of oxygen the body can utilize in one minute. It explains that VO2 max can be improved through training by increasing the four areas that affect it: external respiration, oxygen transport, internal respiration, and oxygen utilization. It discusses different tests to measure VO2 max and three main types of training to improve aerobic capacity - continuous, fartlek, and interval training. Continuous training involves steady exercise for 30+ minutes. Fartlek training incorporates speed variations and terrain changes. Interval training alternates periods of high intensity work with recovery periods.