Editor’s note: This is a lay summary of the new paper, “Potential Mechanisms of the Alexander Technique: Toward a Comprehensive Neurophysiological Model.” See the original paper for a full listing of references. Many of the studies briefly discussed here are described in detail in other posts on this site, linked throughout the essay.
Introduction
Why does the Alexander Technique (AT) have such wide-ranging benefits? Tim Cacciatore, Patrick Johnson, and Rajal Cohen have published a new scientific model arguing that AT works with two foundational aspects of our motor control system: postural tone and body schema. Their model is built on evidence that AT instruction changes the distribution and adaptability of postural tone. They further hypothesize that AT instruction engages with and may increase the accuracy and detail of body schema. According to their model, much of AT pedagogy involves teaching students to positively influence the tonic postural states that facilitate movement and balance and to perceive their bodies more accurately and completely. For convenience, their model will be referred to as the Tone/Schema Model of AT.
The authors bring to their model a unique combination of expertise in both the sciences and AT. Tim Cacciatore and Rajal Cohen are both scientists working in the field of motor control, and Patrick Johnson is a physicist. All three are certified AT teachers. They present the Tone/Schema Model in a paper recently published in Kinesiology Review. While the paper is accessible to non-scientists, this summary is written specifically for a lay audience. The Tone/Schema Model represents an important step in developing a scientific understanding of why and how AT works.
Modeling AT
Building theoretical models is one of the most important parts of doing science. In popular usage, theory is often equated with speculation (“just a theory”), but theoretical models are data-driven and research-based. While individual studies report findings from a particular experiment or set of experiments, a model seeks to build a coherent explanation for findings from many studies. Models can also be used to make predictions and create a program for future research. Although scientific models often have speculative elements, that speculation is informed by existing research. Ideally, any speculation is framed in such a way that it can be tested down the road.
For much of AT history, scientists either did not or were unable (often for technological reasons) to study phenomena at the heart of AT, such as interrelationships between subtle mental and physical states.1 A case in point is the dominance of strict behaviorism in mid-twentieth century psychology. The most famous proponents of behaviorism, such as John Watson and B.F. Skinner, felt that internal mental states were not appropriate topics of scientific study. Mental activity was a “black box.” Their perspective was in large part a reaction to what they felt was self-indulgent, unscientific, introspective psychology of the late-nineteenth century (associated with William James, among others). Whatever the merits of their critique of introspective psychology, strict behaviorism was not a particularly helpful theoretical framework for understanding AT, which is based on attentional and intentional practices. Technological challenges also impacted early research on AT. For example, Frank Pierce Jones attempted research on AT at Tufts University in the 1950s and 1960s. He used a Marey wheel to study patterns of movement. It took him days to collect data that can now be collected in a matter of hours using a motion capture camera system.
Relatedly, there was only a very small body of scientific research on AT. This gave scientists and AT teachers very little data on which to build scientific explanations of AT. This has started to change. In the last thirty years, AT has become the subject of serious scientific inquiry. The Tone/Schema model contextualizes this research on AT within the broader science of motor control, forming a coherent explanation of why and how AT works. The model also lays a foundation for future research, including studies of the possible role of body schema in AT as well as brain areas involved in phenomena seen in AT.
Research on AT
As the scientific research on AT has grown, it has documented a strikingly wide range of effects, from alleviating pain and anxiety to improving aspects of movement, balance, and posture. Clinical research has documented significant reductions in chronic back, neck, and knee pain from AT study. AT has also been shown to be effective for controlling the symptoms of Parkinson’s disease. Studies have found that studying AT leads to reductions in stress, using self-reported outcome measures such as performance anxiety among musicians as well as more objective measures like heart rate and skin-conductance (to assess sympathetic arousal). Research has also documented benefits across an array of movement tasks, from everyday actions like rising from a chair and walking, to skilled performance on a musical instrument. AT also improves breathing, across a range of measures. And studies have documented improvements in static and dynamic balance, including functional reach, a clinical measure of balance. How can AT have such a wide range of benefits?
An intriguing fact about AT is that lessons or classes rarely directly address such specific benefits. For example, AT teachers do not diagnose or treat pain or anxiety. In general, AT lessons also do not attempt to perfect particular movements, practice balance tasks, or impose a specific postural alignment. To give one example, a study that documented improvements in breathing through AT noted that subjects had not practiced specific breathing exercises. AT has what is called in motor control “generalizability,” i.e., something learned in one task carries over to other activities. From a scientific perspective, what is learned in AT that can influence so many different tasks and conditions?
The Tone/Schema Model of AT
Research on postural tone and AT
Postural tone is the ongoing, low-level, automatic muscular activity that stabilizes the body against the forces that act on it, both externally and internally.2To learn more about postural tone, watch Tim Cacciatore’s video lecture, “A Central Role for Postural State in AT,” as part of the 2020 Video Symposium. Preliminary evidence suggests that AT instruction changes the distribution of postural tone from superficial to deep musculature. Both an early study by Frank Pierce Jones and more recent work from Rajal Cohen’s lab have found reductions in the automatic activity of the superficial neck musculature as the result of AT instruction.
Research also shows that AT improves the adaptability of postural tone, defined as the capacity to automatically resist or yield to forces as the situation demands. Tim Cacciatore and colleagues have shown that AT teachers are better at dynamically matching forces that act on the body than control subjects—whether the pull of gravity on the torso when standing up from a chair or an unpredictable push on the back. Cacciatore has also documented that AT training improves the ability to yield to a force, called compliance. Working with Victor Gurfinkel, Cacciatore developed a device that measures subjects’ compliance to very slow rotation. They found that AT teachers have 50% less tonic resistance to rotation than healthy controls and that 20 AT lessons led to a 30% reduction in resistance in subjects with low back pain.
Body schema and AT
Body schema is the unconscious, internal representation of the body used to guide movement and posture.3To learn more about body schema and AT, read Rajal Cohen’s post, “Debauched Kinesthesia and Faulty Sensory Appreciation.” The authors hypothesize that AT instruction improves the accuracy, detail, and completeness of body schema. Research suggests that postural tone and body schema are closely intertwined. Postural tone may be organized in relationship to body schema: sensory information about forces acting on the body (including gravity) is integrated into our internal, unconscious map (or maps) of the body. Postural tone is thought to respond, at least in part, to such maps. If this research is correct, it suggests that changes in distribution or adaptability of tone could be accompanied by changes in body schema, and vice versa.
Another reason that body schema plays an important role in the Tone/Schema Model is that the accuracy and completeness of body-based self-perception is a significant focus of AT instruction. For example, students widely report experiencing changes in how they experience their bodies over the course of lessons, including where movement takes place in the body, how body parts relate to each other, the relative sizes of different parts of the body, and more direct experience of parts of the body that had “disappeared” from body awareness. Research is needed to see if such experiences are the result of actual changes in body schema through AT instruction.
Research on chronic pain, postural tone, AT, and body schema
Changes in the distribution of postural tone could partly explain the alleviation of chronic pain often seen following AT lessons. Research has found that the engagement of deep and superficial musculature is somewhat inversely related, meaning that when deep muscles under-engage, superficial muscles over-engage (and vice versa). Such research may complement findings from Rajal Cohen’s lab. Subjects with chronic neck pain experienced both a significant reduction in pain and a significant reduction in engagement of superficial neck muscles after an AT group class. Though activity of deep musculature was not measured in the study, the model suggests that AT helps redistribute tone from superficial to deeper muscles.
Changes in body schema might also partially underlie recovery from chronic pain. Chronic pain is associated with inaccurate and less detailed (i.e. coarse-grained) body schema. For example, one study found that individuals with chronic osteoarthritis of the hands perceived their hands as smaller than they were. People with chronic hand pain also have trouble with the so-called two point discrimination task, which measures subjects’ ability to differentiate sensations on the hand (for example, contact at one point versus contact at two points). If AT does improve the granularity and accuracy of body schema, the authors suggest, this may be another explanation for why AT is effective at alleviating chronic pain. It could also be the case that certain areas of the body drop out of body schema through neglect or injury, and that the act of engaging with body schema could bring about beneficial results.
Research on adaptive postural tone, movement control, and AT
The most direct evidence for how postural tone can affect movement comes from a study of differences between AT teachers and healthy control subjects when rising from a chair. Cacciatore and colleagues created a deceptively challenging movement task: standing up smoothly and slowly over 8 seconds. AT teachers met the challenge easily, whereas healthy, untrained control subjects could not do so, even with feedback and practice during the experiment. Rather than smoothly rising from the chair, they would slowly lean forward and then suddenly lurch out of the chair.
In the video clip above, the AT teacher (right) maintains a near isometric spine throughout the movement (think of the plank pose), while the control subject (left) experiences more movement along the spine, especially at seat off. The AT teacher moves smoothly, with a gradual increase in foot force (blue arrows in the video). The control subject increases foot force dramatically when lurching out of the chair. What explains the difference?
The researchers used computer modeling to test how changing different parameters might affect the action and found that adjustments in postural stiffness best fit the data. A great deal of postural activity is necessary to maintain the near isometric spine seen in AT teachers during sit to stand. The authors note that it’s unlikely that the AT teachers were just rigid—data from experiments on compliance show that AT teachers are also good at automatically yielding to forces in the back. Just as crucially, the postural resistance necessary to support the back did not interfere with smooth rotation in the hips and knees. Control subjects showed opposite tendencies: they struggled to maintain stiffness necessary for an isometric spine, while possible stiffness in hips and knees interfered with smooth movement out of the chair. This research on rising from a chair highlights one of the key insights of the Tone/Schema Model of AT: sometimes the solution to a movement challenge is a postural solution.4For an in-depth look at what we can learn about AT from sit to stand, read Tim Cacciatore and Patrick Johnson’s post, “The Physics of Sit to Stand,” along with summaries of Tim Cacciatore’s two studies comparing AT teachers and control subjects in rising from a chair: “What Can We Learn about AT from Sit to Stand?” and “How Posture Inteferes with Movement—Evidence from Standing Up Slowly from a Chair.”
Postural tone and the regulation of emotion
While research has documented that AT instruction can decrease anxiety and improve emotional regulation, there has been no research to date about what changes in AT that might explain such benefits. The Tone/Schema Model points to several lines of research that might suggest a role of postural tone in anxiety and stress. These include research on how changes in axial tone might slow breathing and downregulate the stress response, interrelationships between axial motor regions and the adrenal system, and the influence of body states on how we interpret emotion.
How AT may work with postural tone and body schema
The Tone/Schema Model brings together a number of lines of research that give insight into some of the specific strategies used in AT to positively influence postural tone or body schema. In particular, the model helps explicate two important cognitive skills—direction and inhibition.
Activities in AT lessons are accompanied by postural and spatial intentions, termed directions. AT directions differ markedly from more common, effort-based posture cues, such as “tuck the chin,” “pull back the shoulders,” “lift the chest,” “sit up straight,” or “engage the core.” The specific directions used by individual AT teachers vary quite a bit, but may include such intentions as “neck free,” or “up along the spine.” AT instruction emphasizes that directions are to be “thought,” not acted upon.
Rajal Cohen has published two studies looking at differences between a “non-doing” AT-based intention—“lighten up” into length—and more a common, effort-based posture cue—“pull up” into length. She used “relax” as a control. “Lighten up” cues were found to impact postural tone, decreasing axial stiffness compared to “pull up” and improved movement initiation (taking a step) as well as static and dynamic balance. In her analysis, Cohen suggested that “lighten up” influenced subjects’ postural state, which in turn had a positive impact on movement control and balance.
Another important skill in AT is inhibition. Inhibitory control—which includes the ability to control impulses and choose what one is attending to—is known to be important to all learning. The Tone/Schema Model suggests that inhibitory control might be important in AT for switching from more familiar movement strategies to less familiar postural strategies. In Cacciatore and colleagues’ research on sit to stand, control subjects could not help but “lurch” out of the chair, using a momentum-based strategy that was incompatible with the task goal of standing slowly and smoothly. The Tone/Schema Model suggests that inhibitory control could help students prevent such well-ingrained movement strategies that likely forestall the kind of postural learning that would ultimately make standing slowly and smoothly possible. Relatedly, the authors note that AT hands-on instruction often involves unpredictable guided movement, such as between sitting and standing. They suggest that such unpredictable movement challenges the student to let go of (inhibit) movement planning and instead indirectly activate automatic postural strategies.5The Tone/Schema Model views the role of inhibition in AT differently than earlier, proto-scientific models based on a reflex understanding of postural control. For much of the twentieth-century, many AT teachers believed that the role of inhibition was to prevent learned habits that interfered with reflex posture. From this perspective, inhibition was the main mechanism of how AT worked. You inhibited the habit and the reflex took over. In the Tone/Schema Model, inhibition is important, but the model does not view inhibition as the single central mechanism of changes in postural tone. The point can be clarified by comparing inhibitory control in the Tone/Schema Model with inhibitory control in more familiar learning situations, such as playing an instrument or playing chess. Inhibitory control allows time to form a movement plan; i.e. “stop and think through what you are about to do,” as when a musician “mentally practices” a musical passage. Inhibitory control is also at the root of cognitive flexibility, i.e. “check your first impulse and think through other possible responses,” as when encountering an unexpected move by an opponent in a chess game. In the Tone/Schema Model, inhibitory control prevents the habitual movement plan in order to practice postural strategies that cannot be attained through direct means, such as changes in distribution of postural tone and automatically resisting and matching forces. For more about inhibition in AT, see Patrick Johnson’s, “Science of Inhibition and End-gaining.”
Inhibitory control may also be beneficial because of “spreading” effects. The Tone/Schema Model notes that because of the complexity of the musculature of the axial body, problems with axial support, such as stiffness or collapse, tend to “spread” to other areas of the body. Spreading effects might be beneficial as well. A central practice in AT is attending to neck tension. Ian Loram and colleagues studied the use of “selective inhibition” of neck tension in an activity (violin playing). When subjects successfully minimized unnecessary neck muscle movement, they experienced cascading, uninstructed effects—including less jaw pressure on the violin chin rest, less muscular engagement in the shoulder girdle and legs, and lower skin conductance (a measure of sympathetic arousal). Loram’s research demonstrates that it is plausible that positive spreading effects may be consciously employed to benefit different tasks.6Ian Loram’s study used ultrasound to give the subjects real-time feedback on the shape of their neck musculature while playing the violin. Violinist and AT teacher Alison Loram showed similar cascading benefits when using verbal feedback more akin to traditional AT instruction in a separately published Master’s thesis. The Lorams consider “selective inhibition of neck muscle tension” to act as a constraint that induces spontaneous changes in “global control.” For more an Ian Loram’s research, see his video lecture, “Proactive Selective Inhibition Targeted at the Neck Muscles & Model for AT Learning,” as part of the 2020 Video Symposium.
Interestingly, there is some evidence that posture might impact executive functions like inhibitory control. Rajal Cohen’s lab has found correlations between chronic forward head posture and difficulties with tests of inhibitory control. Preliminary research has found improvements in tests of inhibitory control and working memory after AT group classes.
As previously mentioned, a great deal of attention in AT is given to how students perceive their bodies. Hands-on contact in lessons gives students feedback to aid accurate body perception. Teachers may also use mirrors or video to help students discover misperceptions about the configuration of their bodies. AT lessons also often include instruction in experiential, functional anatomy, such as the location of the atlanto-occipital joint or the ischial tuberosities. One intriguing possibility in the Tone/Schema Model is that attention on the body takes advantage of the possible interdependency of body schema and postural tone. By improving the accuracy, completeness, and availability of body schema, body-based perceptual training in AT may indirectly influence postural tone.
Discussion: the explanatory power of postural tone and body schema
To briefly summarize, research on AT has now documented that AT instruction changes the distribution of postural tone and increases the automatic adaptability of postural tone. Research also suggests that changes in the distribution of postural tone may partly explain reductions in chronic pain that accompany AT study, and that increased adaptability of postural tone may explain how AT lessons improve movement control. Because of the possible interdependence of postural tone and body schema, as well as the importance of body-based self-perception in AT, the authors also hypothesize that AT engages body schema. Further, AT instruction influences postural tone and body schema through largely cognitive skills—direction and inhibition—as well as hands-on instruction and the study of body-based self-perception.
Why do postural tone and body schema have the power to potentially explain so many aspects of AT? As the authors point out, in the broadest sense, both postural tone and body schema are fundamental to all aspects of our motor behavior. Postural tone provides much of the stability that makes mobility possible. It helps to stabilize the body in anticipation of, during, and following movement or balance reactions. If postural tone is poorly distributed, or if ongoing stabilization strategies are either unyielding or unable to resist forces effectively, then postural tone may interfere with movement or balance. Similarly, body schema is a key reference used in the planning and control of posture, balance, and movement. Body schema that is inaccurate, insufficiently detailed, or incomplete could have detrimental effects on movement and balance.
The Tone/Schema Model also documents several practical challenges to working with postural tone and body schema that can help explain how AT works. The authors note recent research that suggests that the control of postural tone is likely different—in both the neurocircuitry involved and the patterns of muscular activation—than control of voluntary posture, as when we attempt to “sit up straight” or clench a fist. This apparent difference between voluntary posture and postural tone may help explain why AT emphasizes an indirect approach to posture and usually rejects more common, effort-based postural cues.
The authors also note that postural support in the axial body—the head, spine, ribs, and hips—is especially complex. Postural tone in the torso can be organized in any number of ways, including medial vs lateral distinctions or, as discussed above, superficial vs deep. In addition, research on skilled performance has found that attention on the body can negatively impact many aspects of movement control. The Tone/Schema Model proposes that AT might take advantage of spreading effects by bringing constructive attention to specific parts of the body that then positively influence the rest of the postural system, thus avoiding the dangers of micromanaging the body.
Both postural tone and body schema are conservative systems: persistent and slow to change. Postural tone and body schema are also subconsciously generated and subtle in effect compared to movement. If problems with chronic pain and anxiety are linked to problems with postural tone and body schema, this may help explain why these problems are both so persistent, and why their potential causes are so hard to perceive. Similarly, the persistence and subconsciousness of postural tone and body schema might explain why it takes time to learn and to benefit from AT.
Future Research
The Tone/Schema Model makes a convincing case that postural tone is at the center of many of the effects and benefits of studying AT. At the same time, it lays out an ambitious program for future research. Both postural tone and body schema are active areas of study in the fields of motor control, neuroscience, and psychology. While existing research on body schema suggests that it is relevant to AT, more research is needed to establish that changes in body schema accompany AT training. Research is also needed to more fully document physiological changes that accompany the alleviation of anxiety and chronic pain through AT study.
At the end of their paper, the authors provide a tour of known brain circuitry that could be involved in AT instruction, including the brainstem, basal ganglia, sensorimotor cortex, parietal cortex, cingulate cortex, and prefrontal cortex. This section is almost entirely speculative, as there is only a tiny amount of neuroimaging data on AT. The most popular neuroimaging tool is functional magnetic resonance imaging (fMRI). FMRI research is likely to be impractical for most AT phenomena (as it is with much motor behavior) as subjects must remain lying down and still in the MRI machine. Much research remains to be done that can directly document what is happening in the brain during AT lessons and how AT training might change patterns of brain activity.
Perhaps the most important lesson of the Tone/Schema Model for AT teachers and students is that the interests of scientists studying motor control now overlap directly with the interests of those studying AT. For much of the history of AT, this was not the case—either because dominant theories didn’t study relevant states or because the technology didn’t exist that could measure phenomena relevant to AT. Things have changed. The Tone/Schema Model is possible because of the growth in motor control research relevant to AT as well as research on AT itself. Somewhat amazingly, this more than century-old method is on the cutting edge of current scientific research into the most fundamental questions of the control of posture, balance, and movement. We are just at the beginning of understanding why and how AT works. As we study the current science and absorb its insights, we can prepare for the exciting discoveries that are sure to come.
About the Author
Andrew McCann, M.AmSAT, is an Alexander Technique teacher and violinist based in Chicago. He became involved with Alexander Technique Science after writing popular posts summarizing scientific research for his blog, Alexander &.
Exciting and amazing work !