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Thread: FAO Dingo/McIntire - article on paraspinal muscles

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    FAO Dingo/McIntire - article on paraspinal muscles

    http://journals.lww.com/spinejournal...tebral.17.aspx

    Electromyographic Analysis of Paravertebral Muscles in Patients with Idiopathic Scoliosis

    de Oliveira, Anamaria Siriani; Gianini, Priscila Elisa Siqueira; Camarini, Paula Maria Ferreira; Bevilaqua-Grossi, Débora

    Spine. 36(5):E334-E339, March 1, 2011.


    No abstract available.
    Sharon, mother of identical twin girls with scoliosis

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    Good job Pooka1!

    I have a copy of the study and although the authors couldn't find evidence of muscle imbalance it was a very interesting read.

    Conclusion: In the experimental conditions of this study, there are no differences in electromyographic amplitudes of erector spinae muscles between the concave and convex sides of the curvature apex in patients with idiopathic scoliosis and control volunteers. Further studies should evaluate whether intragroup differences in muscular activation, at the L5 level in 80% trunk extension MVICs with predominance of the left side of spine, it is related to the presence of scoliosis deformity.
    Here is a link to one of the charts in the study. I used a red hilight and a graphic of the spine to show what parts of the back were measured. I hilighted in blue the portion of the spine that showed major asymmetry in both Scoliotic and control children.

    RESULTS
    The mean torque values of the MVICs of trunk extension tests were 12.90 (SD = +/-4.22) Nm for the scoliosis group and 14.17 (SD = +/-5.72) Nm for the control group. Nonpaired t test indicated no signifi cant differences in the levels of effort between the groups in the study.
    Normalized RMS values are present in Table 2. There were no statistically significant differences in the mean normalized RMSs of erector spine muscles between the scoliosis and control groups (P > 0.05).
    The normalized RMSs of the convex and concave sides in the scoliosis group were significantly different (P 0.05) only at the L5 level. The convex or left side produced greater normalized RMS values when the effort was correspondent to 80% of the MVICs of the trunk extension. In the control group, the normalized RMS values were also significantly greater for the left side of the spine, only at level L5, when the effort corresponded to 80% of MVICs of trunk extension.
    Let me try to translate that into English. Please Dr. McIntire correct me if I get something wrong.

    A) Control kids had more muscle strength than Scoliosis kids (14.17 compared to 12.9) but the amount wasn't significant.
    B) Control kids and Scoliosis kids produced roughly the same amount of EMG activity.
    C) At L5 (the bottom vertebrae) there was a significant difference in EMG activity and torque between the convex and concave side of the curve. However this difference was found in both the control kids and Scoliosis kids. I hilighted this in blue on the table graphic I uploaded and linked.

    One thing I thought was interesting was that if I understood the data correctly kids with Scoliosis showed noticably higher EMG activation on both the convex and concave sides during every test at T8 and L2. However at L5 the difference vanished as the back was worked harder (40%, 60%, 80%). The study authors didn't mention this so they might not have viewed it as significant.

    I would love to read Dr. McIntire's insights!
    Last edited by Dingo; 03-05-2011 at 03:00 PM.

  3. #3
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    Dingo, when I clicked on your link my computer had to block a trojanhorse virus. Then it disabled the page and I can't look at it.

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    Rohrer01
    Dang... Imageshack is off my list of image hosters.

    Ok I reuploaded it to postimage and it should be fine. I fixed the link in my previous post as well.

    Study Chart

    BTW the first number in each cell is EMG activity. The second number in parenthesis is torque.

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    Quote Originally Posted by Dingo View Post

    Let me try to translate that into English. Please Dr. McIntire correct me if I get something wrong.

    A) Control kids had more muscle strength than Scoliosis kids (14.17 compared to 12.9) but the amount wasn't significant.
    B) Control kids and Scoliosis kids produced roughly the same amount of EMG activity.
    C) At L5 (the bottom vertebrae) there was a significant difference in EMG activity and torque between the convex and concave side of the curve. However this difference was found in both the control kids and Scoliosis kids. I hilighted this in blue on the table graphic I uploaded and linked.
    The difference in torque isn't significant. I'm actually a little surprised at how small the torque values are. 14 Nm is not that much force, especially for the back extensors. The ~ 1.2 Nm difference is the equivalent of ~1 pound. Torque is also frequently presented in a normalized fashion, usually Nm/lean body weight thus expressing 'strength' in terms of muscle mass instead of absolute torque.

    The similar EMG between control and scoliosis is somewhat interesting. Although I'm curious why they normalized the EMG data to the maximum value. However, even though I've measured EMG I haven't been deep enough in presenting/analyzing the data to know the reasons behind various procedures.

    Definitely a different EMG signal between sides at L5 but showed the same pattern in controls. Which is an interesting finding I think.

    What I notice is the dramatic increase in EMG from 60% to 80% compared to any other jump at any other level. That is, all of the EMG differences from 40 to 60 to 80% amount to about a 10-20% increase in EMG activity. But the jump from 60% to 80% at L5 is about double on the convex (left) side (69 at 60% up to 129 at 80%). There aren't any other increases like that. It makes me wonder if there was something methodologic involved. I don't have a guess what that might be. (Perhaps the kids were using their feet differently during that contraction). It's just a very obvious change that is similar in both groups that doesn't seem to have a physiologic explanation. Particularly, since the EMG values are normalized to maximum EMG activity. So the EMG value should be read as a percent of MVIC. Thus the 80% effort on the left side is 129% of MVIC? Seems a bit odd to me.

    Quote Originally Posted by Dingo View Post
    One thing I thought was interesting was that if I understood the data correctly kids with Scoliosis showed noticably higher EMG activation on both the convex and concave sides during every test at T8 and L2. However at L5 the difference vanished as the back was worked harder (40%, 60%, 80%). The study authors didn't mention this so they might not have viewed it as significant.

    I would love to read Dr. McIntire's insights!
    That they are consistently higher is worth noting. On average it looks like about 10% higher in the T8 region and a little more in the L2 region. And that the convex side is always higher than the concave side even though in the lumbar region these values represent muscles on the opposite side as the thoracic region. But, that also begins to appear as though you're trying to read too much into the data.

    Quote Originally Posted by Dingo View Post
    Rohrer01


    BTW the first number in each cell is EMG activity. The second number in parenthesis is torque.
    The first number is EMG and the parentheses number is standard deviation (SD) not torque.

    Overall, they seemed to have paid a lot of attention to the EMG methods which is nice. But the discussion is a bit thin, physiologically, to be published in Spine and show data that appears to contradict so many other studies.

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    Skevimc

    Thanks for explaining the data.

    I look forward to more studies on this topic but assuming this study is correct that tells me something about Torso Rotation strength training.

    Maybe TRS doesn't correct a strength asymmetry. Maybe it gives the back extra muscle mass that can be used to overcome some other defect in the spine or nervous system. That would explain why teen girls tend to have worse symptoms than teen boys while juvenile boys and girls suffer equally.
    Last edited by Dingo; 03-08-2011 at 12:20 AM.

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    Skevimc

    ... or alternately TRS works for a reason that isn't obvious. Maybe it's not treating a muscle imbalance but instead the symptoms of a nervous system disorder. In the latest study EMG readings for scoliosis kids were higher across the board. Maybe strength training the paraspinals triggers the release of hormones or other factors that lower this excess activity.
    Last edited by Dingo; 03-08-2011 at 08:26 AM.

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    Quote Originally Posted by Dingo View Post
    Skevimc

    Maybe TRS doesn't correct a strength asymmetry. Maybe it gives the back extra muscle mass that can be used to overcome some other defect in the spine or nervous system. That would explain why teen girls tend to have worse symptoms than teen boys while juvenile boys and girls suffer equally.


    ... or alternately TRS works for a reason that isn't obvious. Maybe it's not treating a muscle imbalance but instead the symptoms of a nervous system disorder. In the latest study EMG readings for scoliosis kids were higher across the board. Maybe strength training the paraspinals triggers the release of hormones or other factors that lower this excess activity.
    The more I've thought about it over the last few years, I lean further away from the strength asymmetry as being any type of cause or even solution but rather it is a measurable effect of whatever is going on. I believe that the muscles are weak, and muscle biopsies have shown what appears to be atrophy on the concave side. But, with the assumption that the muscles are capable of functioning properly, the malfunction could be either neural or biomechanical or both, which could be caused by some other, yet to be determined, 'malfunction'.

    Too many 'could be's in that hypothesis.
    Last edited by skevimc; 03-08-2011 at 05:40 PM. Reason: formatting

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    Skevimc

    I remember you wrote that during your pilot study one girl (maybe more) going through the peak of her growth spurt did not suffer progression.

    Does this study help narrow down what might be happening?
    Last edited by Dingo; 03-09-2011 at 12:33 AM.

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    Quote Originally Posted by Dingo View Post
    Skevimc

    I remember you wrote that during your pilot study one girl (maybe more) going through the peak of her growth spurt did not suffer progression.

    Does this study help narrow down what might be happening?

    Not really. This is part of my critique of this paper's discussion. They don't give any reason why they got the results they did and how this might make any kind of physiological sense. It's a straight descriptive study. As I said before, I'm surprised it was able to get in to Spine with such a weak discussion. And even though I know they paid a lot of attention to their methods, their primary result of asymmetry at L5 at 80% in both groups seems very random. And when I come across random findings like that, I tend to doubt them and begin try look for any explanation. This paper doesn't seem to indicate they really questioned their findings and just simply reported whatever numbers came out of their computer.

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    @ Mcintire's last comment...

    You know, if Spine can't hold the line on reasonable discussion sections in their pulished articles, I am wondering if it is even worth reading abstracts from the other journals.

    It may be a rare, isolated occurrence as might happen in any top shelf journal. Still, it gives me pause.
    Sharon, mother of identical twin girls with scoliosis

    No island of sanity.

    Question: What do you call alternative medicine that works?
    Answer: Medicine


    "We are all African."

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    Quote Originally Posted by Pooka1 View Post
    @ Mcintire's last comment...

    You know, if Spine can't hold the line on reasonable discussion sections in their pulished articles, I am wondering if it is even worth reading abstracts from the other journals.

    It may be a rare, isolated occurrence as might happen in any top shelf journal. Still, it gives me pause.
    I think this would also highlight what constitutes a good discussion section. Showing that you've read the literature by discussing how your results compare with others is important. Which they did. But I also think that an attempt at explaining how their results make sense from a physiological standpoint is important as well. And if an explanation can't be readily made then I think stating that point as well, e.g. This result was surprising and is not easily explained. Then followed by a few ideas they might have tossed around, perhaps dealing with right-handedness (all subjects were right handed). And stating, if handedness played a role testing a left handed group would better identify if this finding has a physiological explanation. Something. Anything.

    The more I think about this, the more I tend to really question the findings. From my own unpublished data/observations, the convex side has higher activity and this difference isn't noticeable in healthy controls. My measurements were during treadmill walking, so perhaps the asymmetrical EMG is more noticeable during certain functional tasks?? Admittedly, it was more noticeable in some patients than others. But it wouldn't take a statistical test to prove it. It was "Oh... wow! Look at that."

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    Quote Originally Posted by Dingo View Post
    Skevimc

    I remember you wrote that during your pilot study one girl (maybe more) going through the peak of her growth spurt did not suffer progression.
    Forgot to answer this part of your statement.

    Yes, there were a couple of girls that reduced or remained stable that went through a big growth spurt during treatment and/or follow-up.

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