Knowledge Base


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 > Training Concepts

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.

A cyclist dressed in black rides out of the saddle against a black background

The True Definition of Threshold

Your lactate threshold may not be what you think it is. Coach Trevor Connor explores the true definition of this physiological turn point.

Cyclist riding down a tree-lined road

How to Nail Your Next Taper

How long? How much? How many? Tapering can be a dark art, but we’ve got all your questions answered to help deliver you to your next start line ready to go.

Athlete training at altitude

Fast Talk Labs Q&A #1

We get asked a lot of great—and nerdy—questions via our Fast Talk Labs Forum. Every month we’ll now be taking the best questions and publishing our answers. This month, our in-house physiologist Rob Pickels tackles the topics of altitude training and the impact of body composition on hypothermia.

The Science Behind Going Slow to Be Fast

The concepts of central and peripheral conditioning help explain why an effective training base period leads to speed and durability in the race season.

Fast Talk interval Chris Case

This Is an Interval

Trevor Connor revisits the fundamentals of aerobic versus anaerobic pathways, and helps us understand more advanced principles of interval training.

pro cyclist Fast Talk Laboratories

Pro Training Tips, with George Bennett

We sit down with Jumbo-Visma rider George Bennett to better understand how he trains, how you can apply his tips, and how pros have vastly different approaches.