What is dynamic posture?
I'd like to introduce the idea of thinking about posture as something dynamic, meaning it changes and is flexible, rather than being something static or solid; something one strives to obtain and then maintain.
A dynamic posture is the opposite of a prescriptive idea of posture (the one in which you may have felt pressure to "stand up straight"). Posture is not about 'standing up straight' but is about being in alignment and moving with ease. Having a dynamic approach to posture is about becoming aware of how your posture is at a particular point in time and then allowing changes to happen by easing into ways of standing, sitting or moving that feel better. It's allowing the body to move itself back into balance, rather than forcing it to be something.
I would say that 'good' posture is how you stand and move with ease; how you stand and move without putting undue pressure on any part of your body. Due to injury and stressors in our lives we become unaware of how we are moving and our bodies become out of balance. By enquiring into how you are standing and moving, rather than striving for a pre-conceived idea of 'good' posture, you allow yourself to make different choices and ease into a different, less effortful ways of standing and moving.
By allowing your posture to be dynamic, you allow yourself the space to get back into balance so that you can move, sit and stand with more mobility and freedom.