Gravity pulls on us throughout our entire life and unless you are an astronaut we cannot escape its constant influence. Whatever we do it continuously affects us. Our frame (the skeleton and muscles) gives us a structure and a means to resist it….but it gets tired.
It has been scientifically observed that tight muscles and postures adopted in childhood do not go away when we get older and in fact develop over time. Through our personal history, upbringing, culture, repeated activities, injuries, illness, etc., we each adopt patterns of posture, physical behavior and movements.