How many times did your mom yell at you to “Sit Up Straight!” when you were younger? She obviously thought that good posture was important, but you thought “Whatever…Mom doesn’t know anything”, right? So the question is, does posture REALLY affect back pain, neck pain, or any other kind of musculoskeletal pain? The answer is YES, posture absolutely matters!…But it also doesn’t. Unfortunately, the answer is not cut and dry so I’m going to try to attempt to make it a little less confusing.
Before we get too far, we must learn how your body responds to various stresses. In 2002, Dr. Michael Mueller and colleagues proposed the Physical Stress Theory1 which, in a nutshell, states that tissues adapt to any deviation in load (stress) from that to which it is accustomed. If the load (stress) level is lower than it’s baseline, the tissue becomes less tolerant to stresses, resulting in tissue atrophy. If the load (stress) is greater than what it’s used to, the tissue becomes more tolerant to stresses, resulting in hypertrophy. This makes sense, right? You become a couch potato, you get weaker. You work out, you get stronger. But what happens when the stresses become too large for the tissue to be able to handle? The tissue “fails” and leads to injury, pain, etc. The kicker here is that physical stress is accumulative and it’s not simply defined by the magnitude of the load. It also takes into account the length of time the tissue is exposed to the stress (duration), the number of repetitions the load is applied to the tissue, and how fast the stress is applied to the tissue (rate). Therefore, according to the Physical Stress Theory1, a tissue can fail and become injured via 3 distinct mechanisms: 1) a large load applied over a short period of time, 2) a small load applied over a long period of time, or 3) a load somewhere in the middle applied a large number of times. Let’s get into a little more of the details of each of these mechanisms.
Large Load, Short Duration
Example 1 is probably the most well-known. You may have experienced this type of acute injury first-hand if you have sustained a muscle strain when performing your PR snatch or if you’ve broken a bone during a car accident. You may also have experienced this second-hand if you’ve watched your favorite professional athlete sustain an ankle sprain or broken bone after a bad landing or illegal tackle. This mechanism doesn’t have much to do with the topic of poor posture that we are discussing here. So let’s move on!
Low Load, Long Duration
Example 2 depicts what is, essentially, you sitting at your desk for 8+ hours per day with very little respite. The World Health Organization2 (WHO) has determined that a significant risk factor for the development of musculoskeletal pain in the workplace is muscular inactivity leading to deconditioning, or weakening, of muscles, tendons, and bones. This is thought to be exacerbated by “slouching” which allows your body to rest on passive tension provided by ligaments and muscle stiffness eventually leading to stretched out and weakened structures. However, Dr. Shirley Sahrmann3, a renowned professor and researcher from Washington University in St. Louis, has proposed that, no matter whether the posture is “good” or “bad”, ALL sustained postures can lead to tissue injury and musculoskeletal pain. What?!
Dr. Sahrmann based the statement above on research she performed and a classification system she and her colleagues developed to more specifically guide physical therapy diagnosis and treatment. The key concept of Sahrmann’s classification system is that the body follows the path of least resistance, leading to imprecise movement from the joints (even movements that are so small you might not be able to see them!), pain, and eventual tissue injury. The analogy I like to use involves two springs, one from a trampoline and the other from a ballpoint pen. If you were to take one spring in each hand, hook the springs together end to end, and stretch them apart, the spring from the ballpoint pen would stretch far more than the spring from the trampoline. This is because the resistance from the trampoline spring is significantly greater than the resistance from the ballpoint pen spring and the stretch follows the path of least resistance.
As creatures of habit and, ultimately, lazy creatures, humans tend to assume the same postures and move in the same ways throughout their lives, unknowingly creating paths of least resistance within their body. With this in mind, it doesn’t matter whether the assumed posture is categorized as “good” or “bad” if you are in the same position for 8+ hours, 5 days per week, 52 weeks per year, etc, etc.
Medium Load, Large Repetition
A good visual of the third and final example is a man/woman who works on the factory line and performs the same task all day, everyday. Other examples may include repetitive typing or repeatedly turning one direction to get into a drawer. In small doses, these activities are harmless. However, according to the WHO2, when one activity/movement is performed for long periods of time, significant fatigue of the involved muscles occurs. If there is not sufficient time and an optimal environment for the body to recover, the muscles may undergo irreversible changes in structure. Going back to our spring analogy from above, the more often you pull the springs apart, the more stretched out the spring from the ballpoint pen becomes, until it ultimately fails and breaks.
Putting It All Together. What We Can Do.
The bottom line is that the body likes MOVEMENT! But most importantly, the body likes varied and, even, novel movements. Whether you sit in the best posture or the worst posture for 8+ hours a day, you are likely going to experience some sort of discomfort. Also, if you do the same 2-3 movements for 8+ hours a day, you are likely to experience some sort of discomfort. In order to reduce your risk of developing musculoskeletal pain, the WHO2 recommends a healthy balance of both activity and rest. Specifically, just like any aspect of life, you should avoid extremes: excessive overload and total inactivity.
The first, and best, thing you can do is GET UP AND MOVE throughout the day! Break up the monotony of the workday. The Centers for Disease Control and Prevention (CDC)4 published an awesome resource guide that outlines physical activity recommendations for Americans and provides ideas on how both individual employees and employers can easily incorporate physical activity into the workplace without the need for any equipment or special training. The simplest idea includes getting out of your desk chair at least once every 1-2 hours to perform a stretching routine beside your desk or go for a short walk through the hallways or up and down the stairs. More organized/group ideas include scheduled physical activity breaks that the whole office can perform together, such as a group yoga or tai chi routine, chair aerobics, or a walking discussion group.
The second thing you can do is vary the positions you are in throughout the day. I’m sure you’ve heard about the standing desk craze which began in an attempt to reduce the amount of time sitting while at work. However, some individuals simply went to the other extreme and stood rather than sat for the whole workday. While, yes, more muscles are active when standing as compared to sitting, the same concepts of sustained postures discussed above apply to standing for 8 hours. However, if you have a standing desk, don’t worry, the purchase was not made in vain! Instead, simply alternate sitting and standing every hour or two throughout the day.
With all of this being said, ergonomic desk set up still plays a part in reducing the risk of developing musculoskeletal pain in the workplace. Therefore, don’t be afraid to ask your physical therapist, or other trusted healthcare professional, about proper desk setup/ergonomics and other tips on how to mitigate your risk for musculoskeletal pain in the workplace. You can even ask your trusted professional how to choose and safely begin an exercise routine. We’re always happy to help!
- Mueller MJ, Maluf KS. Tissue Adaptation to Physical Stress: A Proposed “Physical Stress Theory” to Guide Physical Therapist Practice, Education, and Research, Physical Therapy, 2002; 82(4): 383–403, https://doi.org/10.1093/ptj/82.4.383
- Luttmann A, Jaeger M, Griefahn B, Caffier G, Liebers F, Steinberg U. Preventing Musculoskeletal Disorders in the Workplace. World Health Organization. Protecting Workers’ Health Series 5.
- Sahrmann S, Azevedo DC, Van Dillen L. Diagnosis and treatment of movement system impairment syndromes. Brazilian Journal of Physical Therapy, 2017; 21(6): 391-399. http://dx.doi.org/10.1016/j.bjpt.2017.08.001
- Physical Activity Breaks for the Workplace. cdc.gov. https://www.cdc.gov/workplacehealthpromotion/initiatives/resource-center/pdf/Workplace-Physical-Activity-Break-Guide-508.pdf Updated October 2019. Accessed April 2020.