VO2max testing and lactate testing in Boulder Colorado

Physiology

Humans aren’t machines—we’re much more complicated. Exercise physiology involves changes in the body from exercise and rest.

From anaerobic threshold to environmental acclimatization, from FTP to PGC-1 alpha, we explore the science of human performance.

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Physiology > Endurance Training

An ultra-runner summits a mountain peak with the sun low in the sky behind him

An Ultra-Athlete’s Guide to RPE

An athlete’s rate of perceived exertion, or RPE, is one of the most underappreciated metrics. For ultra-athletes who are closely in touch with their bodies and minds, working with RPE is an essential component to training and racing.