Having read his book "Ultramarathon man" recently. I grabbed it and here are some quotes:
"My legs throbbing and cramped" ... "Then without warning the quadriceps and calf muscles of both muscles seized in wicked cramps" ... "The cramps were still so severe that..."
I'm gonna stop there, but ctrl-f finds at least 10 more references.
Really shows how far these pseudo-journalists go for a story. The rest of the portrayal of him being some super human is also completely in opposition with his biography.