Discuss in my forum
By Paige Waehner, About.com Guide
Updated June 10, 2010
About.com Health's Disease and Condition content is reviewed by our Medical Review Board
Fartlek Training Fast Twitch Muscle Fibers Fat FITT Principle Flexibility Flexion Frequency
Full Glossary
Paige WaehnerExercise Guide
©2012 About.com. All rights reserved.
A part of The New York Times Company.