Introduction
I have been giving Rolfing sessions since June 2015. The work approaches the body through the fascia, and posture is what changes. In Rolfing, posture means three things: walking, standing, and sitting.
I have written elsewhere about bipedal walking from an anthropological angle. Here I want to take up one of the muscles that matters most to walking: the iliopsoas.
The muscle that carries the leg forward
The iliopsoas comes up in the fifth Rolfing session. The name covers three muscles — psoas major, psoas minor, and iliacus — although it is also common to treat it as two: the psoas group and the iliacus.
It is the only muscle that joins the upper body to the lower, and it attaches to the front of the spine.
It sits deep in the core, linking the femur, the pelvis, and the spine. From the spine it drops vertically, then crosses the pelvis on a diagonal. Because it connects the two halves of the body directly, it is what balances the body at its center.
Within the group, the psoas major begins at the front of the lumbar spine. Walking happens as the whole iliopsoas shortens and lengthens. That combination of vertical and diagonal supports the upper and lower body the way the arch of a building does.
It also has a good deal to do with awareness of the tanden — the lower belly, the place a person acts from, called bandha in yoga. The iliopsoas runs from the front of the lumbar spine, through the pelvis, to the lesser trochanter of the femur, which puts it close to the body’s center of gravity. When the iliopsoas is available, awareness of that center tends to be available too.
As I described in more detail in Session 5: The Psoas and the Viscera — The Front of the Spine, the muscle is also involved in:
- improving the work of the organs
- deepening the breath, working together with the diaphragm
- improving circulation and nerve function
So the iliopsoas does more than balance the upper and lower body. Its reach extends into a great deal else.
It is known for flexing and extending the hip, and for lifting the thigh. When the psoas major weakens, walking and running are affected: people trip and fall more easily.
How overtraining the abdominals shuts the psoas down
Desk work and inactivity weaken the iliopsoas, but the relationship people overlook is the one with the abdominal muscles. Overtraining them can weaken the iliopsoas.
The sequence runs like this:
- the abdominals, particularly rectus abdominis, which runs from below the ribs to the pelvis, become too strong
- the organs behind them want to move, but the space has narrowed and they cannot
- as the organs lose their movement, the psoas major, which lies deeper still, comes under pressure
- the body becomes one in which the psoas major cannot easily work
The belly is layered from the outside in: rectus abdominis, then the organs, then the psoas major. When the outermost layer tightens, the effect reaches all the way to the innermost.
The muscle of fear?
The iliopsoas connects to the diaphragm, and this is also the region known as the solar plexus. The solar plexus, the manipura chakra, is said to govern the flow of life energy through the body. It is described as regulating the autonomic nervous system and as bearing on the gut — the second brain — and the gut-brain relationship.
The words attached to the solar plexus are trust, fear, intimidation, self-worth. It is held to be an important chakra for valuing oneself, for taking responsibility, for making one’s own judgments. Where there has been trauma that raised anger or fear, this region is said not to move well. In the session room, that is something I have felt.
What Rolfing can do: making room
The fifth Rolfing session is the one that addresses the iliopsoas. It lies too deep in the body to be touched directly. So the work goes to the surrounding muscles and fascia, softening them to widen the space in which the iliopsoas can move.
What is striking is that this is enough. Given the room, the muscle begins to move on its own.
When the legs begin at the ribs
What is interesting is that as the iliopsoas becomes available, walking changes.
Most people walk with the sense that their legs begin at the belt of their trousers. As awareness of the iliopsoas comes in, that shifts: it starts to feel as though two legs hang from beneath the ribs.
The spine lengthens as a result, and lower back pain and stiff shoulders tend to move in the direction of improvement.
Conclusion
This piece has taken up the iliopsoas as the muscle that matters to walking — what it is, why it weakens, and how overtraining the abdominals and experiences of fear and trauma play into that. It has also looked at what Rolfing can do about it.
Note, September 2026
The iliopsoas this piece writes about became, two years later, a full installment of the walking series: “Part 3: The Leg Begins Below the Ribs — The Psoas and the Diagonal.”
Much of it overlaps. That the muscle begins at the front of the spine, crosses the pelvis on a diagonal, and reaches the femur. That it resembles the arch of a building. That when rectus abdominis tightens, the organs lose their movement and the psoas major beneath them comes under pressure. That the sense of the legs beginning at the belt gives way to the sense of two legs hanging from below the ribs.
What differs is what comes after.
Part 3 goes from the psoas to the rotation of the pelvis. Four or five degrees to each side with every step, and that is what produces the stride. The rotation travels up through the spine, and the shoulder girdle turns the other way. That counter-rotation appears as the swing of the arms. And if the pelvis and the shoulder girdle turn in opposite directions, the torso between them twists — and twisted tissue wants to return. That return is the propulsion for the next step.
Walking without swinging the arms is tiring because no twist is made.
This piece stops at the psoas. It says the muscle is the only one joining the upper body to the lower, but it does not go on to what that joining does during gait.
There is one thing here that Part 3 does not have.
The solar plexus, and the muscle of fear. Looking at the psoas from the side of the chakras. Part 3 touches the tanden and bandha, but goes no further in that direction.
Writing from anatomy, or writing from an Eastern view of the body. About the same muscle, there are two ways in.