“Epidemiologic studies have shown that individuals in occupations that involve prolonged periods of sitting experience a high incidence of low-back pain”
I don’t think that this surprises anyone, but as we continue to advance with technology, the jobs that require mostly standing are going away. Put the data into today’s terms. How many of us had cable t.v when we were kids? How many of us had tablets and laptops as kids? I didn’t and was more active because of it. My daughter would be extremely content to watch Curious George on the tablet all day instead of playing. This sedentary nature is hard to break and usually results in crying until she realizes that we are actually going to play. This research demonstrating sitting as a correlation to back pain needs to be looked at seriously, as our society is sitting more on average, at least in my opinion.
“When changing from a standing to a sitting posture…an increased load on the spine as measured by Intervertebral disc pressures.”
The study that this is from is the landmark study for measuring disc pressure. Alf Nacchemson’s study on disc pressures was the first of its kind and mostly likely will never be reproduced again. The subjects in the study allowed a needle inserted into the disc in order to read the pressure. Picture a pressure gauge for a tire and how it measures how much air pressure is in the tire. Now picture the same thing, but with a needle at the end, measuring the pressure in your disc. This is no good. In order to do this, the disc itself needs to be punctured. This is why the study will not be reproduced. No review board would ever approve a study in which the participants have an increased risk of injury…just for the sake of measuring.
“…anular failure and gradual disc prolapse following fatigue loading of lumbar discs wedged in flexion…sitting for 1 hour results in significant changes in the mechanical properties of the lumbar Intervertebral disc…Wilder et al propose that lumbar disc herniations can be a direct mechanical consequence of prolonged sitting.”
Anyone out there just adjust his/her sitting posture?
There is a lot of research demonstrating that sitting is bad for you. This can’t be argued. There is a newer article that states that sitting for one hour, while watching t.v., can take up to 22 minutes off of your life. In the phrase of the show that we are currently watching on Hulu…”YOU ARE THE BIGGEST LOSER!”
“…studies have shown that subjects with or without back pain are more comfortable sitting with a lumbar support in a LP (lordotic position) compared to a KP (kyphotic position).”
If you sit up really tall and elevate your chest, your low back will make a hollowed position…this is called lordosis. When you bend forward, your low back will make an arched position (think the overly slouched position) and this is called kyphosis. Previous studies demonstrated that the slouched position was less favorable than a more upright position…ARE YOU KIDDING ME?! Who doesn’t like holding a good slouched position for hours on end?
“McKenzie describes a ‘centralization’ phenomenon whereby certain lumbar movements and positions result in a change in the distribution of referred symptoms from a distal to a more central location”
OKAY…THIS IS HUGE. I have written about centralization in the past, here, here, here, here, and here, but I’ll cover it again…just for you. If you have pain that started in the back and then moved location, specifically into one of the legs…this is no good. If you have back and leg pain that moves from the leg into the back…this is good. This is the basics of centralization. It’s called a phenomenon because we don’t know exactly why it happens, but there is a high correlation between centralization and a disc lesion (such as a herniation), which can also be found here.
“…Donelson et al reported that 76 patients (87%) demonstrated centralization. Further, all individuals exhibiting this phenomenon did so following extension rather than flexion movements”
Let’s start with this study may be a little biased, but that doesn’t negate the information in the study…it just has to be looked at through a lens that takes this into account. This article is co-written by the man, the myth, and the legend Robin McKenzie. I hold this man in high regard, as do many therapists that practice in the orthopedic setting. He was voted the most influential PT of the last century and that is a title that takes a lifetime of hard work, educating others and helping the public at large. Here’s a quick video of the legend… watch Robin treat a patient. With that said, it was still written by an author that has something to gain from a positive outcome by using lumbar rolls. He has his namesake rolls, so we can expect a good outcome from using the rolls prior to even reading the article. It’s still good information that a person can learn from though.
Ah yes…extension. This means bending backwards such as this video by Yoav Suprun a MDT instructor.
“Excluded from the study were patients with:
- Medically diagnosed stenosis, spondylolisthesis or recent fractures;
- Neurologic motor deficit:
- Surgical intervention for the present episode;
- Apophyseal joint or epidural injections administered within the previous 4 weeks;
- …
6….
- Obvious deformity of acute list or lateral shift or lumbar kyphosis;
- Symptoms of hysteria or anxiety neurosis”
This is important to note that the authors are trying to subcategorize patients that are most likely to benefit from using a lumbar roll with sitting. Not all patients will respond well to extension. Patients with stenosis may not respond to extension. This is not true for all, but is the long standing myth taught in PT school. Patients that come in looking crooked or bent over probably shouldn’t be in this study either. I like the last one though…these authors were trying to think of every patient that may not benefit from a lumbar roll in order to rule out using the rolls on everyone.
“The first 70 patients to present within each of the categories were randomly assigned to either a KP or LP group. Whenever required to sit, the KP group were instructed to do so with their back in a supported but flexed posture. Conversely, the LP group were instructed to sit with their back in a supported but lordotic position.”
This is a decent amount of people in the group so it should give some valuable information. One group had to sit slouched and the other group has to sit upright.
“During their first visit to the clinic, patients were seated on the standard chair and immediately given the questionnaire to complete. They were then seated in their assigned posture for 10 minutes, and the questionnaire was readministered.”
This is actually a pretty good way to test the intervention or “treatment”. A test performed before the treatment and immediately after the intervention is the best way to minimize the number of variables looked at during the second testing. For instance, if I give you an anatomy test and tell you to take the same test after studying and watching t.v and sleeping, it’s hard to say which of the three changed the score on the second test. We can assume studying, but it’s not certain. If all you do is study or sleep or watch t.v., then we can narrow down what would’ve caused a change in score.
“Before leaving the clinic, patients were instructed as to the position they were to adopt, whenever seated, over the next 24-48 hours”
This is the part in which the “scientific rigor” of the study will break down. Over the course of 48 hours, there are so many possibilities of making a pain better or worse and the sitting posture is but one variable. Any outcomes taken after this point waters down the results.
Prior to the interventions, there were no differences between the groups with regards to pain location, leg pain or back pain intensity.
“…while there was a 21% decrease in BPI (back pain intensity) for the LP group, there was a corresponding 14.5% increase in pain for the KP group…reduction in leg pain for the LP group after only 10 minutes of sitting…the very marked reduction in leg pain (56%) for the LP group contrasts with no significant change in pain for the KP group”
There were a greater percentage of patients that responded well to sitting with a more upright posture than those that sat slouched and some of those that slouched actually got worse over time. The advice that out moms gave to stand up tall appears to hold true for some folks.
“…adoption of a LP resulted in 48% of these patients having pain that centralized above the knee after only 10 minutes of sitting…10% for the KP group…24% of the KP group’s pain peripheralized below the knee at POST-TEST 3 compared to 6% for the LP group.”
The first thing to take from this is that an upright posture is not for everyone, in that 6% of those that sat upright actually got worse. Getting worse means that the symptoms that you have from your back actually gets worse into the leg, calf or foot. Now, 48% got better in that the leg pain reduced within 10 minutes. What this means for the patient is that sitting taller is worth a shot if you have pain that radiates into your leg. If you get worse from sitting up tall…stop. It’s really that simple to start with. A lumbar roll could be a useful device to get you to sit more upright. This could be homemade such as a rolled up towel, a purse or a forearm by putting your arm behind your back at about the belly button area.
EXCERPTS TAKEN FROM:
Williams HM, Hawley JA, McKenzie RA, van Wijmen PM. A Comparison of the Effects of Two Sitting Postures on Back and Referred Pain. Spine. 1991;16(10):1185-1191.