Back height has an influence on chair set-up because many fixed back chairs allow angle changes that affect the position of headrests and the support given to the shoulders and back. We provide chairs to accommodate average sized adults, as well as shorter people, children and older users in poor health.
Correct seat width reduces the tendency to lean. If
the tendency to lean lifts one side of the pelvis, the
posture becomes increasingly unstable. One hip
may end up higher than the other, or the individual
may become free to pivot in all directions causing
the pelvis to tilt.
Left unchecked, this leaning posture could lead to
the development of a scoliosis profile where the
spine curves to maintain an upright head position.
Our seat width adjustment helps to laterally
stabilise the pelvis, which makes achieving
a midline position easier.
A chair with the right seat depth ensures the chair back supports the pelvis posteriorly. Without support at the back, the pelvis is likely to tilt backwards and encourage sacral sitting. If the seat depth is too long, the user won't be able to get their buttocks against the back of the chair for support. If the seat depth is too shallow the area over which body weight is distributed may be reduced, which increases the risk of pressure damage.