Metabolic Conditioning Glossary

By Greg Glassman

This article, by BSI’s co-founder, was originally published in The CrossFit Journal. While Greg Glassman no longer owns CrossFit Inc., his writings and ideas revolutionized the world of fitness, and are reproduced here.

Coach Glassman named his training methodology ‘CrossFit,’ which became a trademarked term owned by CrossFit Inc. In order to preserve his writings in their original form, references to ‘CrossFit’ remain in this article.

Download a pdf of the original article HERE.

I want to help with some of the basic terminology of metabolic conditioning, so here's Pukie's guide to easy bioenergetics complete with commentary

V02 max:

Maximum amount of oxygen that can be used continuously divided by body mass. Long the gold standard of aerobic fitness, the slight advantage that endurance athletes have over anaerobic athletes in V02 max can be attributable to the low body mass of endurance athletes. I can use a similar definition of strength – by dividing lifts by weight – to show that little guys are stronger than big guys.


Low powered, low intensity, long duration – more than several minutes. This is the easy stuff. Introduced to real efforts these guys crumble!


Higher-powered, higher intensity, shorter duration efforts– those less than several minutes. Anaerobic is Greek for “worth while.” Pukie wants to know why there are 1 million recreational triathletes but only 7 recreational 800 meter athletes.

Lactate threshold:

The point as work intensity increases where lactic acid levels in the blood rise faster than can be controlled. Lactic acid is a waste product of anaerobic work. Also known as “anaerobic threshold,” the lactate threshold marks the point in intensity where work has become largely anaerobic. This is also the “pussy rest-stop.”

Interval training:

Exercise protocol of set periods of high intensity rest and work. This is how anaerobic athletes develop tremendous levels of aerobic fitness – through intervals. I want to meet the scientist who invented this. How else could you do high intensity work?

Heart rate monitor:

It’s all about the performance. Forget heart rate. The heart rate monitor is a fun toy, though. Mix dehydration, beer, steep hill, bicycle, hot humid day and see who can get the highest number. I’ve seen seven people over 200 at once on the same hill. What can you and your friends do?