🦀 Issue 52 - PF, Posture, No-show, and Functional Disability

This week,

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In PT news, there’s PT Crab. That’s really all I have to say for an intro this week, so let’s dive in!

Plant your flexors! Or Something.

The Gist - Do better walkers have stronger plantar flexors? Yupp. They do indeed. This piece from the Journal of Physical Therapy grabbed 34 studies that investigated the relationship between PF strength, balance, and walking speed to see if they’re related and found weak to moderate associations between the three. Any type of plantar flexor strength metric was allowed, including torque, power, rate of force development, and endurance. And instrumented balance measures were allowed, like force platforms, dynamic platforms, lean and release systems, and more. They split balance into static and dynamic, allowing two different associations there.

Here are the numbers:

Plantar flexor strength has a positive weak association with static balance with an r of 0.20. To refresh on r values, that’s the Pearson Correlation Coefficient. It’s basically how well two lines trend with one another. Two lines with exactly the same slopes get an r of 1, oppo slopes give us -1, and 0 means no association at all. 0.2 is somewhat associated. They both trend up, but not right together.

Moving up the r scale, there’s a moderate positive association of 0.42 between plantar flexor strength and dynamic reactive balance and a slightly larger 0.55 association between PF strength and proactive balance. Walking? Yupp, got those too. 0.29 association between PF strength and preferred walking speed and 0.34 between it and maximum walking speed.

Tell Me More - That was a long gist, I know, but I had to explain how correlations worked. Now that you know that, time to discuss the studies a bit. The biggest thing I have to point out is that all of the above was in older adults. Younger and middle-aged adults demonstrated very different correlations, most of which were not significant. Did you notice how PF strength was more associated with the balance activities? I hope so. That’s because, according to the authors:

In dynamic challenging tasks, a larger amount of muscle torque and activity is required to stabilize joints and compensate perturbation. Considering moderate association with recovery strategies in a forward induced fall in the older age group, this finding probably reflects greater demand on PF muscle strength during this task.

The researchers note that all older people are using a greater amount of their PF capacity to perform these balancing tasks, and that could be why lower max torque is related to balance ability in those people and not in the young and middle-aged.

The discussion section of this paper is a goldmine, so do check it out if you’re interested.

Where’s it at? Here, open to APTA members.

How LBP Changes Postural Muscles

The Gist - This is a super-brief study that compared EMG activity of postural muscles in people with and without recurrent LBP. They were specifically looking to see how the slump posture (that I’m doing right now and you probably are too) changed muscle activation. This was a small study, so they grabbed 11 healthy adults and 10 with LBP, put them in backless chairs and had them flip back and forth from slump sitting to upright. While doing this, they took EMG readings and checked out their spinal-pelvic curvature and pelvic angles. Here’s what they found:

Both groups used muscles differently when slumping vs. sitting upright, but those with back pain had a different pattern. While the healthy controls turned their external and internal obliques, erector spinae, and iliopsoas way down, people with back pain did not. They just turned them down a bit. In slump sitting, LBP people used 67% of the total erector spinae force used in upright sitting while those without used just 24%. Wow.

Tell Me More - The paper has the full breakdown of the measurements across twelve different muscles and the results are quite remarkable, especially when you get down to the hip. There, people with back pain are using more force in slump sitting than straight sitting at 5 of the 6 tested muscles while healthy people use less force in all the muscles. It’s really interesting stuff. This is important because researchers think that we slump-sit to turn down muscle activation. People with LBP don’t seem to do that. The researchers speculate that this phenomenon is due to the structures that normally resist gravity in spinal flexion are not as effective in people with LBP.

Because the study was so small, we don’t know too much about whether this is a bad thing, whether it’s preserved in standing, or whether different types of back pain affect muscular activation differently. We’ll just have to wait and see.

Paper? We got it right here.

And the highlighted version here.

Here’s Why Your Patient Didn’t Show Up

The Gist - At least, here are some predictive factors about why they may not show up. Did you know that PTs have the highest no-show rate compared to other specialties? It’s as high as 57.3% according to this paper. What?! Yea, I know, that’s nuts. This study dug through the data from a PT clinic in a “large, Midwestern metropolitan area with available public transportation.” (I’m betting on Indianapolis or Columbus) Anyway, they had data on 6,595 evaluations, of which 646 were no-shows. With this data, they ran a bunch of regression models and found some interesting stats. Here are some highlights:

• Women were more likely to attend, with a no-show odds ratio of 0.734
  – Just as a note, odds ratio is basically how much more likely it is that something happens under those circumstances. In this case, .734 means that the women were about 27% less likely to no-show.
• Retirees attended much more often, with an odds ratio of 0.650
• Living 5 miles or farther from the clinic gave a no-show odds ratio of 1.31
• Each extra day between scheduling and the actual appointment increased the odds ratio of not showing up by 1.058

Tell Me More - This is mostly just interesting stuff. It helps build out a profile of those who are most likely to show up (women >40 years old) and those least likely (young, unemployed people on medicaid who live more than 5 miles from a clinic). At first glance, this might make someone go “Oh, so we just need more older women to get our numbers up.” And yea, that would work, but it’s not really solving a healthcare problem, is it? This study is a first step toward understanding who doesn’t show up and why and it points out where the major gaps in our healthcare system are. They’re in an unsurprising place, but it’s still important to point out. People who are poorer, unemployed, and younger have trouble getting to PT. What can your clinic do to get these people in? According to this study, scheduling as soon as possible at a clinic as close as possible could be the answer. That won’t fix everything, but it’s the best we can do until we have more information.

Can I see all 8 pages? Sure! But how did you know it was 8 pages? Spooky…. Here it is, free for APTA members.

It’s a New Outcome Measure!

The Gist - This super-short piece from the Journal of Physiotherapy gets a super-short PT Crab coverage too. It’s a one page breakdown of the FDI, functional disability index, a short self-report tool designed for children aged >8 years. The goal is to have an outcome measure that assesses children who have chronic pain to see how much it affects their lives. Most of this one-page is about the clinimetric properties. Do check them out if you’re interested in the numbers. I’m just here to give you the gist.

In the short commentary section, the authors point out that the FDI is easy to administrate, works with many types of pediatric pain, and comes with a three-level classification system to establish disability. Currently, it’s being used in some clinical trials to establish its overall clinical utility, but it looks pretty good. Limitations? It doesn’t assess difference in social relationships across the developmental spectrum, so it’s not perfect yet. Still, a cool new tool.

You can see the actual FDI here.

The paper here.

And my personally highlighted version of the paper here.

That’s the week! Do check out and subscribe to the podcast if you’re interested in an audio version of PT Crab. Details are above and / or in your email already. Please keep sharing PT Crab with colleagues and friends too! It really helps us grow. Cheers!