I wrote in my post “For a Friend”:
When I sit, I can feel the singular location [of self] generate stretch in the ligaments from the sacrum to the sit-bones, and in the ligaments from the sacrum to the pelvic tuberosities (where the hamstrings attach). If the stretch in these ligaments is even, activity is generated in the legs that returns the stretch to ligaments in the front of the abdomen and to ligaments behind the sacrum and lower spine. If the stretch in these ligaments is even, activity is generated that extends the stretch throughout the body, right to the surface of the skin.
With an even stretch throughout the body, the location where consciousness takes place (the location of self) can become the source of action of the body. (1)
In the 6th century C.E. in China, the Buddhist monk Fuxi wrote:
The empty hand grasps the hoe handle
Walking along, I ride the ox
The ox crosses the wooden bridge
The bridge is flowing, the water is still (2)
The handless hold the hoe.
A pedestrian walks, riding on a water buffalo.
A man passes over the bridge;
The bridge (but) not the water flows. (3)
I would say “the empty hand grasps the hoe handle” is a reference to the role of ligaments at the sacrum in generating activity related to posture.
Here’s a summary of a study that confirms that activity is generated by the iliosacral ligaments:
This study (research by Indahl, A., et al.) established that the ligamento-muscular reflex existed between the sacroiliac joint and muscles that attach to the bones that make up the sacroiliac joint. (The study’s authors) suggested that the sacroiliac joint was a regulator of pelvic and paraspinal muscles and, thereby, influences posture and lumbar segmental stability. (4)
The study didn’t include the sacrospinous and sacrotuberous ligaments, even though these ligaments are integral to the support of the sacrum and the spine.
In my experience, stretch in the sacrotuberous ligaments generates activity in the hamstrings, and by reciprocal innervation, activity in the quadratus and gastrocnemius muscles. The quadratus induces stretch in the iliotibial bands (via the tensor fascia), the bands generate activity in the sartorious muscles, and the activity in the legs reciprocates from one side of the body to the other.
Charles Sherrington (one of the godfathers of modern physiology) noted:
But the distribution and occurrence of reciprocal innervation extend beyond cases of mere mechanical antagonism. The reflex influence exerted by the limb-afferents [nerves from the limbs with impulses running toward the brain] on symmetrical muscle-pairs such as right knee-extensor and left is reciprocal. … Here the muscles are not in any ordinary sense antagonistic; not only do they not operate on the same lever, but they are not even members of the same limb, nor do they belong even to the same half of the body. They are, however, activated conversely in the most usual modes of progression—the walking and the running step—though not always in galloping. (5)
I first read about “reciprocal innervation” in the writings of Dr. John Upledger, in a description he gave of his experience lying on salt water in an isolation tank:
At some point my body began to make fish-like movements, as though my pelvis and legs were the lower part of a fish moving its tail from side to side. This movement was nice and easy. The neurophysiologist in me related these movements to an expression of what we call ‘reciprocal innervation’. The principle here is that, when your trunk is bent to the side in one direction past a certain threshold, the muscles on the other side of the trunk contract. In doing so, the nerve impulses are diverted from the side to which you are bent, and those muscles relax. Your trunk now bends in the opposite direction until that side-bending threshold is passed. The nerve impulses are then diverted again to the opposite side, causing muscle contraction and side bending in that direction. (6)
In a seated posture, reciprocating activity in the muscles of the legs can feel like walking, even though the origin of the action is the stretch of ligaments between the sacrum and the pelvis: “walking along, I ride the ox”.
The stretch allowed by a ligament is slight (less than 6% of the total length of the ligament (7)), and yet as the study by Indahl and associates showed, even a slight stretch can induce muscular activity.
I can’t really say why the first and second translations of Fuxi’s poem are so different in the third line. The first translation is:
The ox crosses the wooden bridge
The activity in the legs produces a slight rotation of the pelvis on the sit-bones, clockwise and counterclockwise. If the ox is a metaphor for the ligaments between the sacrum and the pelvis, and the balance of the body remains between the sacrospinous and sacrotuberous ligaments as the pelvis is rotated, then a narrowing of the range of balance of the body ensues. Such a narrowing of the range of balance initiates reciprocal activity between the abdominals and the muscles that attach to the fascia behind the sacrum and the lower back.
I wrote about stretch in the ligaments in front of the abdomen and behind the sacrum and lower spine. As I check the anatomy, I find that the muscle attachments in the front of the abdomen that I assumed were ligaments are instead fascial aponeuroses (broad fascial attachments). I’m not finding any research to suggest that fascial aponeuroses can initiate muscular activity, the way that ligaments can.
What I experience may simply be reciprocal innervation occasioned by the balance of the body, but I think it’s also possible that a “ligamento-muscular reflex” exists between the intervertebral ligaments of the spine and the muscles of the abdomen and lower back.
I have read that a reference to a “wooden bridge” in Fuxi’s day was really a reference to a log across a stream, an explanation that matches well with my experience of the narrowing of the range of balance of the body. However, I’m not able to confirm that explanation; neither do I see any reference to “wood” or “wooden” in any of a dozen other translations of the poem (8).
The second translation I quoted above renders the third line:
A man passes over the bridge
To me, the characterization of what passes over the bridge as “a man” speaks to a particularly human balance. I have written previously about Gautama’s analogy for the third state of concentration (white, red, and blue lotuses that never break the surface of a pond (9)). I believe Gautama’s analogy refers to the balance of the legs, arms, and head around the place of occurrence of consciousness. I would say “a man passes over the bridge” is an allusion to such a balance, with the place of occurrence of consciousness being the bridge.
The last line of the poem is:
The bridge is flowing, the water is still
The place where consciousness occurs suddenly becomes the source of action of the body, the place seeming to flow from moment to moment, while action based on volition or habit ceases entirely, or falls still.
There’s a feeling that accompanies such a transition, according to Gautama:
… it is as if (a person) might be sitting down who had clothed (themselves) including (their) head with a white cloth; there would be no part of (their) whole body that was not covered by the white cloth. (10)
The classics of Tai Chi also suggest a feeling at the surface of the skin, in the last of four stages in the development of ch’i:
With this method of circulating ch’i (Tai Chi), it overflows into the sinews, reaches the bone marrow, fills the diaphragm, and manifests in the skin and hair.* (11)
The classics go on to say:
The internal develops the ch’i; the external develops the sinews, bones, and skin. (12)
“The internal” here is singularity in the location of consciousness. The development of that singularity is described in the analogies Gautama provided for the initial states of concentration (9).
“The external” I would say is the evenness of stretch that unfolds in stages as a consequence of singularity, the stages being represented here by “sinews, bones, and skin”.
*Here’s the way I understand the four stages: “sinews” are tendons that connect muscle to bone, as opposed to ligaments that connect bone to bone, but the words are used interchangeably in the classics–“overflows into the sinews” describes the effect of singularity in the location of consciousness on the stretch of ligaments; “reaches the bone marrow” captures the role of placement of the bones and gravity in reciprocal activity; “fills the diaphragm” refers to the tight connection between balanced stretch and activity around the abdominal cavity and the free movement of the diaphragm; “manifests in the skin and hair” concerns the arrival of a heightened ability to feel dermatomes, as a consequence of the relaxed nerve exits from the sacrum and spine provided by an even stretch of ligaments.
1) For a Friend
2) “Zen’s Chinese Heritage”, translation by Andy Ferguson, pg 2
3) Ch’an and Zen Teaching, Series One by Lu K’uan Yü (Charles Luk); Rider & Co., London, 1960, pp. 143-145. Translated from The Imperial Selection of Ch’an Sayings (Yu Hsuan Yu Lu) [Yuxuan yulu (Imperial Selections of Recorded Sayings / Emperor’s Selection of Quotations)]
4) Serola Biomechanics website summary of Indahl, A., et al., Sacroiliac joint involvement in activation of the porcine spinal and gluteal musculature. Journal of Spinal Disorders, 1999. 12(4): p. 325-30; https://europepmc.org/article/med/10451049
5) “Reciprocal Innervation and Symmetrical Muscles”, Professor C. S. Sherrington, University of Liverpool, Nov. 13, 1912; parenthetical added
6) “Your Inner Physician and You: Craniosacral Therapy and Somatoemotional Release”, John E. Upledger, p. 165
8) “Zen Literature” on Terebess, https://terebess.hu/zen/fuxi.html
9) The Early Record
10) MN III 94, Pali Text Society Vol. III pg 134
11) “Master Cheng’s Thirteen Chapters on T’ai-Chi Ch’uan”, translated by Wile, 1st ed pg 17
12) Ibid, pg 39