If you look up the actual definition of the word “Sisu” on Wikipedia, you will find the following excerpt sums it up pretty well:

“Sisu is a Finnish term loosely translated into English as strength of will, determination, perseverance, and acting rationally in the face of adversity. However, the word is widely considered to lack a proper translation into any language. Sisu has been described as being integral to understanding Finnish culture. The literal meaning is equivalent in English to “having guts”, and the word derives from sisus, which means something inner or interior.”
- “sisu” definition, http://en.wikipedia.org/wiki/Sisu 

As perfect as this word is in the context of CrossFit and what we stand for as a company, we can’t take all the credit for finding it.  Mikko Salo, the winner of the 2009 CrossFit Games, brought the term to our attention.  Mikko came to The Games as an unknown CrossFitter, unaffiliated with a CrossFit gym.  A fireman by day and CrossFitter by night, he dominated the games and exuded the character we felt embodied the athleticism and sportsmanship we aspire to promote in our gym.

The following video is a brief documentary on Mikko and his journey to and during the 2009 CrossFit Games (also available on the CrossFit site):