Maximal aerobic speed: methodological implications and unintended consequences

Area of Science:

• Exercise Physiology
• Sports Science
• Biomechanics

Background:

• Maximal aerobic speed (MAS) is crucial for endurance performance, representing the highest speed sustainable with maximal oxygen uptake.
• Current methods for determining MAS lack standardization, leading to potential inaccuracies in performance assessments.
• MAS is influenced by both maximal oxygen consumption (V̇O_2max) and running economy (O₂ cost of running).

Purpose of the Study:

• To critically evaluate the assumptions and limitations of common MAS determination methods.
• To propose a more objective and reliable approach for assessing MAS.
• To enhance the accuracy of physiological profiling for athletes.

Main Methods:

• Analysis of three dominant MAS determination approaches: loss of linearity, linear extrapolation, and direct division of V̇O_2max by O₂ cost.
• Exploration of the theoretical underpinnings and practical flaws of each method.
• Comparison of the sensitivity of each method to variations in O₂ cost at different running speeds.

Main Results:

• The loss of linearity method lacks objectivity in MAS determination.
• Linear extrapolation is susceptible to significant errors, especially when O₂ cost changes at the extremes of the tested speed range.
• The direct division method, using V̇O_2max and race-relevant O₂ cost, offers a more robust assessment.

Conclusions:

• Existing MAS determination methods have inherent flaws that can compromise accuracy.
• A simplified approach dividing V̇O_2max by the O₂ cost of running at a race-relevant speed is recommended for improved objectivity and practicality.
• This revised method can be readily integrated into standard laboratory testing protocols.