VO₂max is one of the main indicators of aerobic capacity, but it does not fully explain performance in endurance events. Two athletes may have similar VO₂max values and still differ significantly in sustainable speed and race results.
This happens because performance depends not only on the maximum amount of oxygen the body can use, but also on how effectively that capacity is utilized during exercise.
What Does VO₂max Actually Represent?
Maximal oxygen uptake (VO₂max) represents the highest rate at which the body can take in, transport, and use oxygen during intense exercise. It reflects the integration of the respiratory, cardiovascular, and muscular systems.
In sports such as running and cycling, high VO₂max values indicate strong aerobic potential. However, this potential does not independently determine the speed an athlete can sustain over an extended period.
Movement Economy: The Cost of Maintaining Pace
Running or cycling economy directly influences the relationship between oxygen consumption and speed. It represents the energy cost required to maintain a given intensity.
Imagine two runners with the same VO₂max. If one requires less oxygen to run at the same speed, they have better running economy. In practice, this means they can maintain that pace while using a smaller proportion of their maximal aerobic capacity.
This difference can be decisive in long-distance events, where small variations in energy cost accumulate throughout the race. Therefore, an athlete does not necessarily need a higher VO₂max to run faster. They may simply be more economical.
Physiological Thresholds and Sustainable Speed
Another key factor is the intensity an athlete can sustain relative to their VO₂max. Physiological thresholds help explain how the body responds as exercise intensity increases and how well a given effort can be maintained.
Two athletes with the same VO₂max may have different speeds associated with their physiological thresholds. An athlete who can sustain a higher intensity tends to maintain a competitive pace for longer without reaching levels of exertion that become difficult to sustain too early.
In endurance sports, knowing maximal oxygen uptake is not enough. It is also necessary to understand how much of that capacity can be used during a race and for how long.
Fatigue Resistance and Performance Maintenance
The ability to sustain effort also depends on factors such as muscular adaptations, substrate availability, hydration, and nutritional strategies during competition.
During prolonged exercise, fatigue can reduce an athlete's ability to maintain their target power output or pace. Athletes with similar VO₂max values may respond differently to this process, particularly as exercise duration and intensity increase.
Nutrition also plays a role. Adequate carbohydrate intake during prolonged events helps maintain energy availability, while fluid and electrolyte replacement should account for individual needs and environmental conditions.
These factors influence the ability to sustain performance and make use of physiological potential throughout a competition.
How Can This Be Applied to Training?
VO₂max is a valuable metric for assessing aerobic capacity, but it should be interpreted alongside other variables. Movement economy, physiological thresholds, and fatigue resistance help build a more complete picture of an athlete's profile.
In practice, training should not focus exclusively on increasing VO₂max. Depending on individual needs, improving movement economy, increasing sustainable intensity, and developing fatigue resistance can be equally important.
Combining these adaptations allows training to be tailored to the actual demands of competition, rather than relying on a single indicator to measure an athlete's overall progress.
Conclusion
Two athletes with the same VO₂max do not necessarily achieve the same performance. Movement economy, physiological thresholds, and fatigue resistance help explain why similar aerobic capacities can lead to different speeds and race results.
In endurance sports, the difference lies not only in how much oxygen the body can use at its maximum, but also in how effectively that capacity is utilized to sustain effort throughout a race.
