3-minute read / 2-minute video + 4-minute video

Our modern world is foundationally established on our ability to sit down. From our first days in school and throughout our professional careers we are required to sit. It is challenging for this writer to come up with occupations that do not require this sedentary posture. Consequently, improving one’s mastery of sitting will provide lifelong benefits. For those of us who were brought up sitting, by parents and grandparents for whom sitting was also routine, getting a better seat on the issues arising from sitting and the relevant biomechanics will enhance our vigor and vitality.

The Chair is a relatively recent innovation. Our ancestors, and the vast majority of the world’s population, either squat if they are actively engaged with the gravity field, or sit crossed legs if relaxing. When squatting (feet flat on the ground and making a ~90° angle) our innate tensioning mechanisms stabilize our structure. We can rest in this posture indefinitely. When sitting with legs crossed, as long as we maintain our spine over the pelvis we are also facilitating regeneration, as opposed to degeneration of our core structure. For us, in managing our use of chairs, this is the key point and focus of this discussion – understanding how to position the pelvis to support our spines.

We have bones upon which we sit. These are called Sit Bones, or formally the Ischial Tuberosities. If we are unaccustomed to sitting on these bones, they can be a bit painful when they make contact with a hard surface. This is because we build comfortable furniture, which attempts to distribute loading over the widest possible surface. This antagonism between Comfortable vs. Supportive is the Holy Grail of ergonomic furniture design as they present as intrinsically antithetical. Consequently, our Sit Bones are usually underused and tender when applied to their ordained task. It is easy to adapt to this uncomfortable sensation by rolling our pelvis back off of the Sit Bones. However, when we do this our Spine collapses in an arc leaving the head forward of our gravitational midline and held up by activation of the muscles of the back. This is a significant source of the plethora of chronic neck, shoulder and back issues that plague industrialized societies.

When sitting in a regular chair it can be challenging to get our sit bones underneath our spines. It is much easier when sitting with the knees lower than the level of the pelvis. The easiest way to accomplish this is to sit on a stool. If you sit on a relatively firm stool it is quite easy to feel the Sit Bones contacting the top of the stool, and also how the Spine can then “stack” on top of the Pelvis. When working at a desk, it is healthier for the desk height to be set so that you can work at it either sitting on a stool or standing. When sitting in this manner one can use the feel of the Sit Bones contacting the stool to orient and reset how our spine is stacking. You may need to toughen up your Sit Bones somewhat before this feels comfortable, but this writer recommends the effort as the alternative is persisting in accommodating the tenderness to the detriment of your global structural wellbeing. With practice reorientation of the Spine referenced to this sensation of contact between the Sit Bones and the sitting appliance becomes automatic, suggesting that it engages an innate postural reflex that has been sidelined in advanced societies. This sensation is immediate neuromotor feedback for adjusting postural dynamics, as opposed to other postural feedback sources, many of which do not arise to our awareness until expressed as pain. It is a variant of, or more accurately a subset of Postural Extension, which is the set of postural reflexes engaged in standing and walking. These comments may seem esoteric, but the effect can be experienced by the simple act of sitting on your Sit Bones on a firm stool with your knees below your hips and then noticing how your head tends to automatically orient to center on top of the spine.

It is quite common for people to not actually know where their Sit Bones are, or even that they have them. This short video discusses them and their role in supporting the Spine:

Sitting on the floor. European elementary education is done on the floor – desks not used in some countries till 4th grade.
/using a Zafu
/yoga ball


This writer recommends watching this video for an overview of squatting biomechanics:


Overview of discussions on the Spine:

Overview of the Biomechanics of Posture:

Overview of discussions on our Locomotive Core:

Overview of discussions on our core neurophysiology: