Time to Put it to Rest
Movement always needs to be described relationally. Something moves in a particular direction relative to where it started—we need to have two points of reference to define a direction of movement. Additionally, something needs to move relative to something else:
- The head moves relative to the trunk—cervical movement.
- The femur moves relative to the pelvis—hip movement.
- The humorous moves relative to the scapula—gleno-humeral movement.
- The talus moves relative to the tibia—ankle movement.
Back in the golden age of physical therapy, when patient visits were unrestricted and documentation requirements were minimal, we were blissfully ignorant of the fact that bodies are integrated. When doing a bicep curl, we presumed scapular stability because it was the origin bone and, by definition, wouldn’t move. We took for granted that the hip flexor would flex the thigh (insertion) relative to an immobile pelvis (origin) because it was written in plain language and in black and white in the anatomy books. With classic therapeutic exercise, we assumed both scapular and pelvic stability.
Thanks to Joseph Pilates and others who observed what can, and often does, happen to the scapula (anterior tilt) with a biceps curl or to the pelvis (anterior tilt and rotation) when a leg is lifted while supine (hip flexor contraction), we know/realize/take into account the fact that muscles are actually two-way streets. They act upon and have the potential to move either or both bones that they are connected to.
Though in reality either or both bones could conceivably move, by convention we have assigned the role of stability/origin to the more proximal bone and the role of mobility/insertion to the more distal partner:
- The trunk is the origin—the head is the insertion.
- The pelvis is the origin—the femur is the insertion.
- The scapula is the origin—the humorous is the insertion.
- The tibia is the origin—the talus is the insertion.
New Assumptions Made
We have consequently developed an entire system of exercise based on dubious assumptions:
- The trunk should not move (stays stable as an origin) when the head does.
- The pelvis should not move when the legs do.
- The chest or scapula should not move when the arm does.
- The tibia should not move when the foot does.
We have even coined a modern-day mantra to codify this belief in unmoving origin and moving insertion— proximal stability facilitates distal mobility—anything else is cheating, substitution or compensation. This is a common collective belief about the relationships between limbs and trunk that lures us away from more promising possibilities. It’s not that it’s not true, it’s just not always true, or even mostly true. In functionally relevant, real-life movement, it’s only occasionally true.
Additionally, there is a special subset of origin/insertion thinking that has led us astray in the most fundamental manner. This is the question of who is/should be in control of the pelvis. Joseph Pilates famously stated that the waist or core muscles are the powerhouse of the body, then designed exercises that trained pelvic control from the waist. When you define the pelvis as the origin, when you state either explicitly or implicitly that the pelvis should not move when the hip muscles contract or when the lower extremities move, you have no logical choice but to use the waist muscles to stabilize the pelvis or to prevent it from moving.
There are then two major characteristics that define static integration principles:
- The pelvis is or should be controlled by the muscles of the waist—this is a corollary of origin/insertion thinking that also has its roots in therapeutic exercise. We have been teaching supine posterior pelvic tilts utilizing the abdominal muscles since our first rehab ancestors emerged, goniometer in hand, from the primordial ooze.
- The (arms/legs/neck) limbs move relative to a stable trunk—something moves in relation to something else that is stable or static.Origin and insertion thinking, plus the luggage it engenders, carried forward from old localize and isolate ideas. 1960s therapeutic exercise with a veneer of intentional stabilization of the proximal part.
Today’s Heresy is Tomorrow’s Orthodoxy
How could it be otherwise? Isn’t this the way it has always been? Isn’t this the way it’s supposed to be? Isn’t this what everyone keeps saying? Not necessarily. There are other ways of thinking about movement that precede our modern ideas of static integration. While not always explicitly stated, there are exercise systems or movement traditions that imply very different ways of optimally organizing the body.
We can call these dynamic integrated movement systems, or we can say that they embody competing dynamic integrated movement principles. And, these exercises have been just lying around on the ground, preceding our arrival on the scene, free to the taker, patiently waiting to be discovered, analyzed, modified, justified, medically articulated and utilized to the great benefit of our professions, our patients, and all of mankind. Look for a description of these concepts in next months’ blog.