Because our morphology is unique
Measurements taken in an adult population (1) show that the ideal height, depth and width of a seating area vary greatly from one individual to another.
For example, in a sample of 600 people aged between 53 and 106 years, the measured seat height (at the popliteal fossa, behind the knee) varied between 38 and 54 cm.
And even for a given height there were significant differences: when selecting individuals measuring 169 cm (± 2 cm) the seat height varied between 42 and 53 cm, the seat depth between 45 and 55 cm and the width between 33 and 45 cm.
our seating position is generally poor in a one-size-fits-all chair or armchair
While clothing and sports equipment are offered in several sizes, seats (armchairs, chairs, stools or sofas) are essentially offered in one size.
Thus the height of a chair is about 46 cm. On this chair Marie, who is 1.50 m tall, has her feet in the air, while Max 1.90 m has knees too high and aching pins. On a sofa with a deep seat Max is sitting comfortably if he stretches his legs out while Marie has a very bad posture with a rounded back.
custom-made can help to have a correct sitting posture to prevent back pain.
The seat of these sofas or armchairs available in one size is often too deep. The first consequence is that the seat rests on the leg at the popliteal fossa, at the back of the knee, impeding venous return. The second consequence is that the back does not rest on the backrest; the pelvis pivots and the spine becomes rounded. A custom-made seat helps to correct these defects so that your back rests on the backrest.
It is also important to have armrests at the right height so that your arms can rest on them without raising your shoulders; if the armrests are too low, you will lean to the right or left to lean on them and if the armrests are too high, muscle tension can develop in the cervical area.
a seat adapted to your height is also more comfortable
It allows for a better distribution of pressure and thus improves traffic flow.
For a comfortable sitting position in an armchair it is important that its dimensions correspond to our morphology. A seat height and depth adapted to our body increases the surface area of the body in contact with the seat, reduces pressure on the pins and provides a more even distribution of pressure on the seat. The absence of excess pressure at the ischium allows for better circulation and delays the pain signal that tells us it is time to change position.
At the time of writing I am sitting in a train seat that is too short and too low for my 170 cm and after an hour's journey I am constantly changing position to reduce the pressure at the ischiums and thus allow the blood to circulate and nourish my tissues.
the custom-made seat also allows you to personalize the seat according to your activities.
When resting, a very inclined seat is preferable; the weight of the upper body rests partly on the backrest, which helps to make the seat more comfortable (less pressure on the pins) and improves lateral stability when dozing off.
On the other hand, for activities (eating, working, playing, ...) the reclined position is not practical and a straighter seat is necessary.
For example, to eat a seat inclined at 3°, to read a seat inclined at 10°, to sleep a seat inclined at 30°, ...
The rocking chair has a variable seat inclination which has two effects.
The first one is a transfer of the supports from the front to the back of the chair and vice versa, thus avoiding prolonged over-pressures and the resulting pain.
The second is to facilitate falling asleep or to facilitate soothing by a rocking movement at the level of the inner ear.
to make a seat to your size several data are necessary
In order to make a custom-made chair or armchair, it is necessary to know at least the height, width and depth of the seat adapted to an individual. We offer you a guide to simply take these measurements at home using a simple meter.
(1) source DINED TU Delft.