Today's podcast is the third of our Olympic themed podcasts.  One of the great Exercise Physiologists joins us today - Dr. Ed Coyle from the University of Texas.  Dr. Coyle is with us in advance of the London Olympic Marathon to talk about whether a human will ever run a sub-2 hour marathon.  Dr. Coyle also talks about his past work with Lance Armstrong measuring his exercise capacities.  This is a fun conversation with one of the best physiologists of our time.