The Diaphragm

by | Aug 17, 2023 | Uncategorized

How do you stretch your low back and
strengthen your diaphragm at the same time?

Many years ago, after long shifts of teaching of up to 8 hours straight, I found great relief for my lower back by simply hanging prone over the ladder barrel. I subsequently called the stretch “The Dangler.” No one ever forgot that stretch!

See the Image 1 & 2.

The Dangler, over an arc I made to fit my reformer. Of course, a ladder barrel or StretchFit Combination Station will suffice, and will probably be more comfortable.

The StretchFit Combination Station is a more comfortable option. Ensure the legs either dangle or are non- weight bearing.

The trouble with the Dangler was that although it worked, I didn’t understand why. That’s never been sufficient for me, especially when I want to teach it to others. When teaching clients, and passing knowledge on to other teachers, I feel it’s a duty to understand your material in depth.

So, I asked the head of the school of Medicine where I had been studying clinical anatomy. Dr Gerry is a very generous man, giving freely of his time and incredible knowledge. Below, you’ll see his eloquent reply to my questions about the Dangler. First, let’s have a look at the anatomy and function of the diaphragm.

The anatomy and function of the diaphragm

The thoracic diaphragm is a dome shaped muscle that separates the chest and abdominal cavities. The contractile part of this muscle is located peripherally, inserting onto a central tendon that is not connected to a bone. See Image 3.

Image 3: The central tendon in white, to which all the contractile tissues (muscles) of the diaphragm attach. The muscle fibres of the diaphragm are oriented primarily along a vertical (up-down) axis of the body.

The origins of the muscle are divided into costal and lumbar portions. The “costal” portion originates from the inner surface of ribs seven through twelve. See Image  4. The “lumbar” portion has both medial  (closer to the midline) and lateral (further from the midline) aspects. The medial aspects of the diaphragm arise from the front of the first three lumbar vertebrae. (L1-L3). See Image 4. They are described as the right and left Crura (Latin for legs.) 

Image 4. Showing the costal and lumbar portions of the diaphragm including the right and left Crura.

The lateral aspects arise from three tendinous arches. The first tendinous arch is associated with the abdominal aorta, and the second and third with the psoas major and quadratus lumborum muscles, respectively. See Image 5

Image 5 shows the lateral aspects of the lumbar portion of the diaphragm. The arches permit the passage of the psoas major and quadratus lumborum.

The diaphragm is the principal muscle that causes 3 dimensional “shape change” in the thoracic and abdominal cavities. Leslie Kaminoff, author of Yoga Anatomy coined the phrase “shape change” to describe the actions of the diaphragm during exercise. As we will see shortly, it is this action that creates the low back stretch during the Dangler.

Because the diaphragm has multidimensional action, the type of movement and, therefore, shape change (and potential stretch) it produces depends on which region of its attachment is stable, and which is mobile. You can think of diaphragm the as either a belly bulger, or a rib cage lifter. 

During relaxed belly breathing, often called abdomino diaphragmatic inhalation, the following occurs:

  • the domes of the diaphragm move down in a fairly piston like action
  • the lower abdominal wall is relaxed and pushed forward by the diaphragm
  • the intercostal muscles actively hold the chest wall in a stable position
  • the rib cage remains about the same size in all parts of the breathing cycle

During what is called Thoraco-diaphragmatic breathing the above is reversed –the contraction of the diaphragm then causes expansion of the rib cage. Here’s what happens:

  • the diaphragm presses down against the abdominal organs
  • the abdominal wall is relatively taut, in part from muscle contraction, or from “splinting”

(see below.)

  • the intercostal muscles maintain the overall integrity of the chest wall
  • the rib cage is flared at its base by the costal attachment of the diaphragm

In both cases, exhalation is a relaxed process and occurs through the elastic recoil of the chest wall, diaphragm and lungs. Regular practice of diaphragmatic breathing has acalming effect on the mind while, at the same time, potentially strengthens the diaphragm.

Engaging the abdominals during exhalation passively stretches the diaphragm by raising the intra-abdominal pressure and lifting the abdominal organs upward against the muscle. Note that engaging the abdominals on exhalation also tensions the thoraco-lumbar fascia, which may serve to stabilize the lumbar spine and sacroiliac joint.

Back to the dangler!

So, what happens during the Dangler? As I said above, the Dangler always provided me with a terrific stretch, and a deep sense of relief. It felt as though my lower back was decompressing, as though a weight had been lifted and that I was growing a little taller. Unsure of the anatomy I asked Dr Gerry. Here’s his response: 

The answer is simple with the aid of our principles of general anatomy. Any muscle that is restricted in its movement (e.g. lying over a barrel in this case, thus splinting the diaphragm) will pull excessively on its origins. Of course, the diaphragm has a vertebral attachment to L1/2/3, so these vertebrae will be pulled slightly cephalically (with an angled force), thereby distracting slightly, L3/4. It will probably have a lesser effect on the lower lumbar joints. It will probably also pull up the lower ribs, stretching QL and the intrinsic back muscles. I think you have hit on an interesting observation that, as I said is a beautiful principle-based one. 

So, there you have it! With the descent of the diaphragm restricted/splinted by the barrel, contraction results in the costal part of the muscle elevating and expanding the middle and lower ribs laterally, stretching those muscles (quadratus Lumborum in particular) that attach to them. Although it sounds exceedingly complex, the Dangler is simple to perform.

With some understanding of the dangler, it’s time to give it a go. Test the stretches below carefully. if you have an exercise /swiss ball, make sure it is stable and use it as an alternative.

Be sure to come out of the stretch with great caution. Sometimes, the facet joint capsules may catch, and the muscles may spasm if you are too hasty in your descent.

Of course, visit your nearest StretchFit studio if you would like assistance.

The Dangler

Standard: Any 

Muscle Emphasis: Entire posterior spinal muscles, posterior disks, posterior portion of internal obliques, transversus abdominus, quadratus lumborum

  • A & B. How to stretch
  •  Lie over arc as pictured, explore different postions.
  • Hold for several minutes.

How to breathe:

  • Take deep abdominal breaths to expand abdominal region.
  • Allow legs to dangle if comfortable.


  • Slide out of this position

very slowly onto knees.

  • Brace/contract abdominal

muscles before standing back up

The quadratus lumborum

The quadratus lumborum is a muscle of the posterior abdominal wall. It is irregular and quadrilateral in shape and broader below than above. See Images 6 & 7.


 It originates by aponeurotic fibers into the iliolumbar ligament and the internal lip of the iliac crest for about 5 centimetres (2.0 in). It inserts from the lower border of the last rib for about half its length and by four small tendons from the apices of the transverse processes of the upper four lumbar vertebrae.

Occasionally, a second portion of this muscle is found in front of the preceding. It arises from the upper borders of the transverse processes of the lower three or four lumbar vertebrae, and is inserted into the lower margin of the last rib.

FunctionThe quadratus lumborum can perform four actions:

1. Lateral flexion of vertebral column, with ipsilateral contraction

2. Extension of lumbar vertebral column, with bilateral contraction (based on line of force
passing ~3.5 cm posterior L3 rotation axis)

3. Fixes the 12th rib during forced expiration.
The quadratus lumborum assists the
diaphragm in inhalation

4. Elevates the Ilium (bone), with ipsilateral
contraction (“hip hiking”)

How much does your diaphragm actually move?

The answer to this question depends on how deep of a breath you take and what part of the diaphragm you are asking about.

 The diaphragm is a sheet like dome-shaped muscle (when it is relaxed). Upon contraction, it flattens out and presses down on the abdomen. The net result is a negative inspiratory pressure, which draws air into the lungs. Tidal or resting breathing results in smaller movements of the diaphragm, while vital capacity breathing (as in a deep diaphragmatic breath) results in much larger movement. This is where you take a complete full inhalation. The posterior, or back part of the diaphragm exhibits the greatest excursion; the amount of diaphragmatic motion decreases progressively as we come forward. Image 8 illustrates this. 

MRI studies have accurately quantified diaphragmatic motion during deep breathing, with the posterior region moving an average of 10 cm (about 4 inches) between inhalation and exhalation. This decreases progressively moving forward, with the most anterior portion moving about half that of the posterior. Diaphragmatic motion decreases by about one-third in the sitting position compared to lying on your back.