When playing a sport, doing exercises or training, as the intensity level increases, the body consumes more oxygen; up to a point where the body cannot consume more oxygen and the anaerobic energy system plays a more predominantly role, than the aerobic system.
Maximal Oxygen Uptake (V̇O2 max) can then be defined as: the highest rate of oxygen consumption attainable by the human body during maximal or exhaustive exercise. The V̇O2 max depends on several factors, primarily genetics and fitness level. To understand this in more practical terms, take a look at the diagram below:
The point at which oxygen consumption plateaus (or levels off) defines the individual's maximal aerobic capacity. It is considered one of the best indicators of cardio respiratory endurance and aerobic fitness. However, may be more useful as an indicator of a person's aerobic potential or upper limit than as a predictor of success in sports.
V̇O2 max is usually expressed relative to bodyweight because oxygen and energy needs are a function of body size. Sometimes it is also be expressed relative to body surface area, which may be a more accurate when comparing children and oxygen uptake between sexes.
The most accurate way to determine the V̇O2 max is by doing lab tests. However, there are field tests such as the Beep, Yo-Yo and others that can be used to determine the V̇O2 max. Also, utilizing some models (Jack Daniels ) in combination with ACMS guidelines , the V̇O2 max can be estimated can from actual race data or from a qualitative fitness assessment. The AeroRadar feature in the training and testing applications does these estimations.
The lactate threshold is defined, as the intensity level point where the blood lactate level begins to accumulate faster than the body is able to keep up with lactate production.
The above diagram shows the point at which the accumulation of lactic acid in the body starts to increase more rapidly. This point defined as the “Lactic Threshold” is a very good indicator of the anaerobic fitness levels.
As the V̇O2 max, the most accurate way to determine the lactate point is by doing lab tests. However, for trained people, utilizing the same models as for the V̇O2 max, one can estimate the lactate threshold pace. The AeroRadar feature in the training and testing applications does this estimate.
The diagram also shows the four primary training zones, which are discussed in another section. Please visit the page on “Training Zones”.
The next section discusses the effect of training on maximal oxygen uptake and lactic threshold