Sessions 4, 5, and 6 organize the medial line by way of what lies above the pelvis — the psoas major, the sacrum, and the spine — and what lies below it, the pelvic floor and the adductors: Session 4 working from the adductors to the area of the pelvic floor, Session 5 the psoas major and the diaphragm, Session 6 the spine and the sacrum.
Session 5 continues from Session 4 with the medial line in awareness. What differs from Session 4 is that the work runs mainly along the front of the body, organizing the upper body. Session 6 works along the back.
In Session 5, the key to the medial line of the upper body is the psoas major.
The psoas major runs from the femur to the spine, from the thoracic vertebrae down to the lumbar. It participates in flexion and extension at the hip joint, in lifting the thigh, and in the forward tilt of the pelvis. When the psoas major weakens, the effect on walking and running is considerable. In a gait that lifts the thigh, the psoas major goes unused, the muscles of the thigh and calf are overworked, and fatigue comes easily. Tripping becomes more likely.
Using the psoas major, then, reduces the burden on these muscles and makes walking easier. For Rolfing, which observes the movement of gait, it counts among the most important muscles. And this muscle governs the balance of front and back, left and right, inside and outside.
What is interesting is Ida Rolf’s observation that the balance between the abdominals — the rectus abdominis, shown in the photograph below — and the psoas major matters. Overtraining the abdominals pulls on the body, producing a rounded back and low-back pain, and leaving the psoas major less able to work.
An interesting discovery: my yoga practice involves a great deal of deliberate engagement of the abdominals. The Rolfing sessions made it possible to see that this may have cost the psoas major its ease of movement, its freedom.
Structurally, the psoas major joins the leg to the spine, so it exerts a significant influence on the medial line. Being one of the deep muscles, it is approached while releasing the tension in the fascia around it.
The psoas major also connects to the spine. Considering the organizing of the front of the upper body and the medial line, awareness of the connection from the psoas major to the area around the neck and clavicles matters. For this, the fascia of the peritoneum and the pleura needs releasing.
Among the muscles related to the peritoneum are the quadratus lumborum and the abdominals — the rectus abdominis, the transverse abdominis, and others — and the point lies in how mobility is given to these.
Finally, the work reaches the pleura, the interior of the sternum and clavicles in particular, and the diaphragm. The psoas major and the upper body connect along the medial line, space widens, and the breath can deepen.
Stated more explicitly, the goals of Session 5 are:
- Organize the medial line around the pelvis: the quadratus lumborum, the twelfth rib, and the psoas major, including the psoas minor and the iliacus.
- Organize the medial line of the upper body along the front: around the clavicles and the sternum, the diaphragm, and the thigh muscles as needed.
Body reading runs much as it did in Session 4, with the addition of whether there is a left-right imbalance when the body is seen from the front — the frontal plane, in anatomical terms. The image of two long cylinders, one on each side, serves to read that imbalance. The forward or backward tilt of the pelvis, and the state of the abdomen along the torso, are observed as well. The observations of my own body:
- The chest is under compression from above and below — from the neck above, from the rectus abdominis below (same as Session 4).
- There is a left-right difference between the torso and the legs (same as Session 4).
- Kyphosis in the thoracic spine is pronounced (same as Session 4).
- Bringing the medial line into awareness, the upper and lower body come apart — awareness around the ribs and abdomen is especially thin.
- Effort in the abdominals intensifies the compression of the chest.
What matters, as described last time, is the compression of the chest. Tension around the abdomen presumably contributes to it. The aim of this session was to release the tension in the rectus abdominis and in the psoas major, through work around the abdominals and on the psoas major itself.
The work therefore proceeded lying face up: reaching the upper body around the clavicles, the sternum, and the diaphragm, while releasing tension in the pelvis, the muscles of the lower body — the thigh muscles, the iliotibial band, the hamstrings — the area around the lower back at the quadratus lumborum, and around the abdomen at the rectus abdominis and the transverse abdominis. It closed with work on the psoas major. The work felt so good that there were moments of losing consciousness to drowsiness.
As covered in Session 4, the characteristic of my walk is that effort enters the psoas major. The rectus abdominis, connected to it, is pulled upward, and with abdominal breathing dominant over thoracic, the pull from the neck and the clavicles leaves the chest under compression. The thoracic spine lengthens and the lumbar shortens, and the back ends up rounded.
This time again, the closing stretch went to releasing unnecessary tension while walking — the psoas major, the clavicles to the chest, and the movement around the neck. What became apparent on receiving Session 6 is that tension around the fascia and muscles of the sacrum was what kept the psoas major from releasing. The details come in Session 6.
Note, August 2026
This piece records a second discovery about what the yoga practice had left in the body.
“My yoga practice involves a great deal of deliberate engagement of the abdominals. The Rolfing sessions made it possible to see that this may have cost the psoas major its ease of movement, its freedom.”
Session 4 observed the dominance of abdominal breathing and connected it to years of Ashtanga yoga practice (see “Session 4: Organizing the Pelvic Floor“). Session 5 brings a different facet into view: the manner of engaging the abdominals had taken the freedom from the psoas major.
The pattern of breathing, and the use of the muscles. The same practice had left its traces along two routes.
This piece also touches on Ida Rolf’s own observation that the balance between the abdominals and the psoas major matters. Overtraining the abdominals pulls on the body, produces a rounded back and low-back pain, and leaves the psoas major less able to work. For a yoga practitioner, this is not an observation to set aside.
The question is not whether yoga is good or bad for the body. It is that which muscles one attends to, and where one habitually applies effort, settle into a postural pattern. The longer the practice continues, the deeper the trace runs.
What the front alone could not release
The closing line of this piece reads:
“What became apparent on receiving Session 6 is that tension around the fascia and muscles of the sacrum was what kept the psoas major from releasing.”
Session 5 is the session that works the front of the body: rectus abdominis, transverse abdominis, quadratus lumborum, diaphragm, the area around the clavicles and sternum. Working through the front in full, the tension in the psoas major remained. What released it was the back — the sacrum and the spine — in Session 6.
In fact, when Session 6 brought a seated exercise for increasing the mobility of the sacrum, the effort left the psoas major, and breathing through the chest became available without much effort (see “Session 6: Organizing the Sacrum“).
This is an instance of the bidirectionality — Palintonicity — written about during this same period (see “Basic Concepts — Bidirectionality (Palintonicity)”). The body forms a pair, front and back; releasing one side alone returns to where it started if the tension remains on the other.
The reason the ten-series places the front in Session 5 and the back in Session 6 lies here as well. The order carries meaning, and one side alone does not complete it.
It stands as a record of confirming that in the body, from the position of receiving the work.