Running Speeds
I used to like watching the Special forces selection process TV shows. They would claim that mostly people failed due to mental fortitude. The problem was repeatedly in these shows you would see people who weren&#x27;t fit enough, whose muscles were not capable of the physical strength and stamina necessary to push like this.  Many had trained very hard and were in very good shape but they just couldn&#x27;t sustain it in the cold. These peoples bodies broke down too fast. Mental fortitude only seemed to come into it when you got down to the final few, 90% of people their bodies failed before they got to the point where mental fortitude mattered.<p>I can well believe there are multiple factors that goes into being able to make it through such a test or being very fast. We just don&#x27;t understand these genetic factors yet.