Does the way we attend to our posture affect our balance? Crucially, might some ways that physical therapists, fitness trainers, and movement teachers cue posture actually increase the risk of falls in their patients or students, especially older adults? These questions animate the latest study from Rajal Cohen’s team at the Mind in Movement Lab at the University of Idaho (Cohen et al., 2020). The study contrasts two ways of thinking about posture—common effortful posture cues versus less common effortless posture cues—and asks how they each affect balance in older adults. The results contribute to a growing body of research that suggests it’s time to change how we think about posture.
Fall Risk in Older Adults
As we age, our risk of falling increases, and the consequences of falls are more dire. Every year among adults older than 65, there are thousands of fatal falls, millions of non-fatal injuries from falls, and billions of dollars in medical costs for treating falls. Not surprisingly, this increased risk of falling is associated with a decline in static and dynamic balance, meaning our ability to remain upright while standing still and while moving. As we get older, our joints and muscles get stiffer and our posture gets worse. As a result, older adults tend to use more “voluntary strategies” for balance and movement. In other words, they have to think more about what they’re doing and about how to stay in balance while they’re doing it.
Unfortunately, consciously thinking about body parts involved in an action often impairs the performance of that action. As athletes and performing artists sometimes put it, “You think, you stink.” This creates a possible catch-22 for aging adults: they need to think more about what they’re doing, but thinking can make control worse. The researchers wondered if a way out of this problem was how older adults thought about posture—would both effortful and effortless intentions towards posture degrade balance?
This study is concerned with postural state, which includes both alignment and postural tone. When we colloquially talk about posture, we usually are referring to postural alignment—the arrangement of body parts in relationship to gravity. Alignment can be important. For example, habitually holding the head forward of the torso (called forward head posture) is associated with increased chronic pain, decreased respiration, and increased risk of falls in older adults (Baer et al, 2019). But just as important is postural tone. Postural tone is the persistent, low-level muscle activity that keeps us from collapsing in the field of gravity and that enables us to withstand the forces our musculature produces while we move. You can think of postural tone as how our alignment is organized and maintained.
Contrasting Instructions that Influence Postural State
This current study builds on results from Dr. Cohen et al’s 2015 study showing how different postural instructions affect people living with Parkinson’s disease. They found that people with Parkinson’s disease had less postural sway, smoother onset of walking, and less “axial rigidity” (measured by slowly and smoothly rotating the torso) when applying effortless “Lighten Up” postural instructions than while applying either effortful “Pull Up” instructions or during “Relaxed” standing.
“Pull Up” instructions were based on popular conceptions of posture—that poor posture is the result of a weak “core” and that people need to effortfully pull themselves up to their full height. “Lighten Up” instructions were based on the mind-body practice called the Alexander Technique and suggest that people stop “pulling themselves down” and instead lighten up into length. Such “effortless” postural instructions can also be found in practices such as Feldenkrais, Tai chi, and Aikido. “Relaxed” standing was used as a control.
In this sequel study, Cohen et al. looked at how these contrasting postural instructions would affect balance in healthy older adults.
Assessing Balance, Alignment, and Postural Tone
The new study brought 19 healthy older participants (average age of 69) into the lab one at a time. Each participant was given a chance to practice the three contrasting postural instructions, described in this new study as “Effortful,” “Light,” and “Relaxed.” They then used the different instructions while performing two tasks: standing for 30 seconds on a foam mat (a static task), then performing a 3-second foot lift (a dynamic task involving standing on one leg). A motion capture camera system was used to analyze the subjects’ alignment and how their bodies were moving in space, and electromyography (EMG) was used to measure the activity of muscles of the trunk.
The researchers were primarily interested in the effects of the different postural instructions on how steady participants were during both static and dynamic balance tasks. If you picture someone standing on one leg, you may imagine them swaying in different directions to maintain balance. If the person jerks back and forth abruptly, they probably have reduced balance control and an increased fall risk. Similarly, if they sway a lot, their body traces a longer path through space, leading to a longer “path length” and a more variable position of the center of mass, both of which suggest an increased fall risk.
What the Study Found
Somewhat surprisingly, postural alignment was not statistically different across the different sets of instructions, although there was a tendency for the head to be about half centimeter farther forward in the “Relaxed” condition than in the other two conditions. However, there was quite a large difference in physical effort. Compared to “Light” instructions, the “Effortful” instructions led to an 81% increase in total iliocostalis muscle activity and a 28% increase in peak external oblique muscle activity. The participants’ subjective experience matched the EMG data. Participants reported more mental and physical effort during the “Effortful” condition than during either “Light” or “Relaxed” conditions.
Was this extra effort worth it? No. The “Light” instructions led to less jerkiness and a shorter path length in postural sway during quiet standing than the “Effortful” instructions, suggesting better static balance. And the “Light” instructions led to a longer time standing on one foot and a steadier center of mass during the foot lift task, suggesting better dynamic balance.
Interestingly, participants lifted their foot just as high in all three conditions; this shows that their lower steadiness in the “Effortful” condition was NOT a result of lifting the foot higher. Thinking “Light” improved balance without impairing performance of the dynamic balance task.
Changing How We Think About and Cue Posture
It is hard to overstate how common effort-based approaches to posture are, not only in colloquial understandings of posture—think of teachers and parents exhorting children to “sit up straight and pull their shoulders back”—but in exercise and movement classes, and even in posture advice from leading medical providers. This study shows that such effortful postural advice may have unintended negative consequences on balance, at least in older adults. It’s part of a growing body of research that shows that traditional conceptions of posture have little to no benefit, whether during exercise, rehabilitation, or the ergonomics of home and work.
The study also has implications for research on how conscious thought can impair performance. In this study, conscious intention to “lighten up” posture led to improvements in balance and circumvented the “you think, you stink” problem. The researchers point out that the conscious instructions were “decoupled” from the task. Subjects thought about postural state—specifically focused on the torso and neck—while engaged in a balance task. They suggest that this “indirectness” of postural instruction may help explain why conscious intention did not interfere with the performance of the task. This makes instructions that influence postural state a potent area of research for scientists interested in balance and skill learning.
There are many activities available to older adults that aim to improve balance, and there is promising evidence that dance, Tai chi, and exercise classes can reduce the risk of falling. It may be that the way in which posture is cued in these classes makes a difference in their effectiveness. The “Lighten Up” instructions used in the study, though derived from the Alexander Technique, were simplified so that they could be used by any practitioner. (Verbal instruction in Alexander Technique lessons is usually accompanied by hands-on guidance.) This suggests that physical therapists, fitness trainers, and movement teachers of all sorts could benefit from using “Lighten Up” to cue posture, so that they don’t unintentionally make balance worse and increase the risk of a fall in their older students and clients. As important as alignment is, it may be even more important that we lighten up about it.
The full paper can be read here:
Cohen, R.G., Baer, J.L., Ravichandra, R., Kral, D., McGowan, C., Cacciatore, T.W. (2020). Lighten up! Postural instructions affect static and dynamic balance in healthy older adults. Innovation in Aging. https://doi.org/10.1093/geroni/igz056
You can read a summary of Dr. Cohen’s previous “Lighten Up” study here: https://alexandertechniquescience.com/general/study-summaries/lighten-up-parkinsons/
The full paper for the previous study is here:
Cohen RG, Gurfinkel VS, Kwak E, Warden AC, Horak FB. (2015). Specific postural instructions affect axial rigidity and step initiation in patients with Parkinson’s disease. Neurorehabilitation and Neural Repair. 29(9). (pp. 878–888. doi: 10.1177/1545968315570323
To learn more about how thinking can impair performance, see this review of the literature by Gabrielle Wulf, a leading researcher in the field:
Wulf, G. (2013). Attentional focus and motor learning: a review of 15 years. International Review of Sport and Exercise Psychology. 6:1, 77-104, doi: 10.1080/1750984X.2012.723728
Diane Slater and colleagues discuss the need to rethink posture in this accessible review article:
Slater, D., Korakakis, V., O’Sullivan, P., Nolan, D., & O’Sullivan, K. (2019). “Sit Up Straight”: Time to Re-evaluate. Journal of Orthopaedic & Sports Physical Therapy, 49(8), 562–564.doi:10.2519/jospt.2019.0610
Eyal Lederman documents how traditional ways of viewing and assessing posture can’t explain either pain or the recovery from pain in PT and manual therapies:
Lederman, E. (2011). The fall of the postural-structural-biomechanical model in manual and physical therapies: exemplified by lower back pain. J Bodyw Mov Ther Apr;15(2):131-8. doi: 10.1016/j.jbmt.2011.01.011