Because of our deeply entrenched habit of falling backwards in routine sitting, we have grown utterly out of touch with the force of our falling -- how we are controlling it and how it is affecting us. We have little, if any, awareness of (1) the talus being our balance point; (2) there being a 'strong part of the foot'; (3) the weight bearing sensations on the bottom of the foot, and how we create them.
Thus, when we stand, we rarely use the strong part of the foot. Instead, we overly depend upon our 'safety net' -- not just when some unusual circumstance makes it necessary, but constantly. This compels us to tense leg mucles to brace us so that we do not topple over completely. This not only costs us dearly in wasted energy, but it locks up ankle, knee and/or hip joints, limiting our freedom of movement. And, because our legs are now so tight, providing a hardened base of support, our spine is 'free' to continue to fall in its customary backward direction, which distorts its natural shape.