Have you watched this video?
Fuel for Muscle Contrations gone over by Dr. Gregory Ellis - YouTube
Dr Greg Ellis talks about the use of fatty acids instead of glycogen. He knows A LOT about this, but i myself am struggling to find more about this topic. Take a look at my thread in the primal nutrition part of the forum where some people have given their experiences. Hopefully we can get some more info on this topic as i would really like to know more!