Once upon a time you were born. And you were born with a certain deposit of life force, essence, vitality. Let's call it qi (and pronounce is "chee"). Each day of your life you use some of this qi until one day, after a long and happy life, when all your qi has been used, you will die. The quality of your qi when you were born depends on a bit of luck, on karma, on the health and vitality of your parents when they conceived you, and when your mother carried you in the womb. You couldn't change your inherited qi even if you wanted to or tried very hard to.
But, there is another kind of qi that you acquire each day of your life. You derive this qi from the air you breath, from the food you eat, from the quality of your life and relationships. Good food, good exercise and good relationships add to you store of qi. A poor quality of life consumes qi faster than you acquire qi.
There is good news. If you acquire qi faster than you consume it, you store your qi and this stored qi acts as a buffer between your acquired qi and your inherited qi. In this way, you use your inherited qi at a slower rate. You live longer and the quality of your life is better.
When illness strikes, it takes a large toll on your qi. The more acquired qi you have stored, the better you will fare with illness. If you develop the skill, you can even transfer some of your stored qi to others when they need it. You can be an energizer of others. You can help them be well.
Of course, you cannot escape death when all your inherited qi is finally used, but you can have a long and fulfilled life.
Not a bad myth as far as myths go! Where does taiji fit in the myth? Taiji is a wonderful way to acquire qi. Taiji is energy work. As you develop taiji practice, you can feel qi in your body. You can feel its movement. You can feel where there are blockages of qi It takes time. It takes daily discipline. But, it is well worth the effort.