Posture or attitude?
Personally, I prefer to use the term postural balance or alignment, to avoid instinctively thinking about what is, in reality, defined only as "posture".
Attitude is the way you present yourself to others that reflects a particular state of mind or a kind of choice. To put an attitude into practice, we must coordinate and arrange all our members, but we still cannot talk about posture. Posture is something more internal, which has to do with balance and with the force of gravity.
Whatever this balance is, it must be natural: it cannot be sought as a "one-off", to give a speech or a performance, because the equilibrium itself is inevitably something dynamic, always on the move. In fact, it's enough stretching one arm because the rest of the body compensates the imbalance that is created, making it frivolous and every type of unnatural posture even more rigid.
Posture is adopted more or less unconsciously by a person, defined indirectly by their way of presenting themselves to others indirectly, that is part of the mask that has been built up to show to the world in order to protect themselves from their own fears. Unfortunately, we hardly ever tend to assume the best posture. In any case, it is true that virtually everyone, sooner or later develop problems from back pain.
Correcting this incorrect attitude should be the first step for those who want to regain your voice, if you want to be an actor, a singer, a voice over artist, a journalist, a teacher, a business leader and so on.
The proper alignment of the body, accompanied by a muscular balance and natural diaphragmatic breathing, is the basis of any teaching that deals with the body in its entirety, from sports activities to simply walking: so it will appear obvious to everyone that one part of vocal training cannot be overlooked or left to chance.