Posture and Movement Science Series — The Science of the Relationship Between Gravity and the Body

Introduction

The postures observed in a Rolfing session are three: sitting, standing, and walking. Nearly all of daily life is made of these three, and the patterns inscribed in the body appear here.

This series traces the relationship between gravity and the body along those three actions. From the anthropological finding that humanity held more than 300 ways of sitting, through the metabolic effects of sitting for long periods, the mechanism of the antigravity muscles, the mechanics of bipedal walking, and on to the concept of Tonic Function.

One idea runs throughout. Gravity is not an enemy to be overcome; if the body is organized, it becomes the greatest ally. This was the thinking held by Ida Rolf, the originator of Rolfing, and the series examines it from the side of science.

Six parts.

Part 1 — What Is the Difference Between Squatting and Sitting: The Influence of Chair Culture on the Body

The 300-odd ways of sitting classified by the anthropologist Gordon Hewes. The memory of bodily culture held in the two Japanese characters 坐 and 座. The talar squatting facet as a record of adaptation. And the study finding that Kenyan teenagers, who hardly ever use a backrest chair, had back-muscle strength 21–41% greater than urban teenagers.

→ For those entering from anthropology and cultural history

Link: https://rolfing-zero.hidefumiotsuka.com/en/2024/02/17/86018/

Part 2 — Why Sitting for Long Periods Is Bad for the Body: The Science of Visceral Fat, Chronic Inflammation, and Stress

The problem is not sitting, but a motionless state continuing for a long time. Four risks traced from physiology: the accumulation of visceral fat, the decline in the metabolism of blood sugar and triglycerides, a rise in cortisol, and the inactivation of muscles.

→ For those who want the science of desk work

Link: https://rolfing-zero.hidefumiotsuka.com/en/2022/12/09/87850/

Part 3 — Why “Standing” Is Not Tiring: The Mechanism of Gravity and the Antigravity Muscles

The three conditions of a way of standing that does not tire — a neutral pelvis, the S-curve of the spine, and the position of the head. And Palintonicity, two-directionality: the lower body heads toward the ground while the upper body extends toward the sky. When both hold at once, standing requires almost no energy.

→ For those who tire from standing work or long periods on their feet

Link: https://rolfing-zero.hidefumiotsuka.com/en/2026/03/14/87855/

Part 4 — Why “Walking” Is Fundamental to the Human Being: The Science of Bipedal Walking, Weight Shift, and Gravity

Walking is not slow running. The inverted-pendulum model and the spring-mass model are mechanically distinct. The pelvic rotation that produces stride length, the linkage of arm swing and trunk rotation, and the effects walking brings to cognitive function and mood.

→ For those who want to review the body through gait

Link: https://rolfing-zero.hidefumiotsuka.com/en/2026/03/21/87863/

Part 5 — Why Good Posture Is Not a Matter of Muscle Strength: Tonic Function and Its Relationship to Gravity

Tonic Function, proposed by Hubert Godard, the French Rolfer and neuroscientist. The superficial Phasic system governed by the alpha motor nerves, and the deep Tonic system governed by the gamma motor nerves. And the four perspectives that support Tonic Function — Coordination, Perception, Meaning, and Structure.

→ For those entering from the theoretical core of the series

Link: https://rolfing-zero.hidefumiotsuka.com/en/2026/04/26/87692/

Part 6 — Why a “Comfortable Posture” Exists: From the Perspective of Gravity, Fascia, and Rolfing

Comfort is not laziness but the height of efficiency. Why does a consciously corrected posture return to the original? The structure by which fascia remembers posture, and Daniel Siegel’s concept of integration, close the series.

→ For those who want to begin with the conclusion

Link: https://rolfing-zero.hidefumiotsuka.com/en/2026/04/29/87827/

Reference — Articles Written on Tonic Function

Tonic Function, treated in Part 5, is covered individually and in more detail in these articles.

Gravity and Posture — Understanding the “Transient” and “Sustained” Muscles That Work Under Gravity
Tonic Function ①: The Foundations of Rolfing’s Scientific Theory
Tonic Function ②: Tonus and Bidirectionality
Tonic Function ③: Space (Its Relationship with Spatial Awareness)
How Do the Gravity-Related Tonic Muscles Keep the Body in Balance?
How to Relate the Body’s Movement to Tonic Function?