In a way, “fitness” is really remaining relaxed physiologically, when under physical load or stress. What we “see” is a change in breathing. To not have any fitness means to have low physical load (absolute, not relative) and be tense physiologically. We see this as “moving slow, breathing fast.” To move fast and breathe slow...

When I was doing a lot of endurance racing (running/triathlon), I entered a race called the Woodford to Glenbrook trail race. It was 25km run along a fire trail in Sydney’s Blue Mountains. A pretty fast course. I think we were finishing it in under 1:40 I was in a pretty good position for this...