Health depends on obedience to physical laws, requiring careful discipline and regulation of habits, much like athletic training.

Original passage

We cannot be too often reminded that health does not depend on chance. It is a result of obedience to law. This is recognized by the contestants in athletic games and trials of strength. These men make the most careful preparation. They submit to thorough training and strict discipline. Every physical habit is carefully regulated. They know that neglect, excess, or carelessness, which weakens or cripples any organ or function of the body, would ensure defeat.