What I meant is that the human species is naturally gifted for endurance running. We're not naturally gifted for underwater activities, we're not really designed for flying, but running at a moderate speed for long periods of time is something that we're naturally good at (and specific parts of our bodies are specifically designed in a way that helps with that activity).
The reason why we need to read books and get interested in the theory is especially because we're culturally evolved in a way that doesn't require for us to run around all day long. The skills associated with running are now almost obsolete when they were absolutely crucial back in the days of hunting and foraging for food. As a result, we've kind of lost touch with the minute details of what makes for efficient running, just like I'm not sure a lot of people would know how to make a fire in the wild anymore, those activities are a bonus now, not a necessity.