On muscle imbalance and scoliosis

[Pooka1]

Okay there are a lot of posts on muscle imbalance with the thought that this is somehow the cause and if it can be addressed, progression can be stopped and perhaps reversed.

In my ceaseless efforts to learn how to ride and train horses, I have had the luxury over the years of not only taking a bazillion lessons but auditing five bazillion lessons.

What becomes obvious is that not only does almost every person have a stronger side but EVERY horse has a stronger side.

Lower level riders struggle to feel this sidedness and force themselves to come exactly even.

Upper level horses who are trained to follow/turn from small differences in weighted seatbones will TELL you how uneven you are if you try to ride a straight line without reins or legs... just from weight cues in the seat.

Because most people don't make it out of the lower levels, I suspect one reason is they never even out their sidedness. In some cases, these people CANNOT turn the horse in a particular direction just from their weight because they are so one-sided in their strength.

The points I'm making are as follows:

1. Most people have a strong and weak side.
2. Some people have a VERY marked difference in their strong and weak side.
3. Most people don't have scoliosis.

It is impossible that they all have scoliosis. It is impossible that even those with very marked side to side strength difference have scoliosis. It's too many. The incidence of scoliosis would be much higher in the population if true.

Clearly, any muscle sidedness associated with scoliosis is most likely an effect, not a cause.

And ps... although every horse I've ever ridden had a strong and weak side, I've never met one with scoliosis yet.

[MissEmmyF]

I don't think it's the "cause" of the scoliosis. I agree that it's most definitely the "effect." Something initiates the scoliosis to begin (no one REALLY knows what causes this), and it then pushes around the muscles and other supporting structures around the spine. However, since the only treatment we have for scoliosis is "symptomatic" (i.e. we treat the symptoms of scoliosis and not the cause of scoliosis), it makes sense to at least aim to make the muscles more even. That's the best and most logical treatment we have right now (aside for people that are at surgical levels where surgery is really the only answer).

[Pooka1]

I don't think it's the "cause" of the scoliosis. I agree that it's most definitely the "effect." Something initiates the scoliosis to begin (no one REALLY knows what causes this), and it then pushes around the muscles and other supporting structures around the spine. However, since the only treatment we have for scoliosis is "symptomatic" (i.e. we treat the symptoms of scoliosis and not the cause of scoliosis), it makes sense to at least aim to make the muscles more even. That's the best and most logical treatment we have right now (aside for people that are at surgical levels where surgery is really the only answer).

Well two things...

1. I suggest there are any number of folks who appear to think the muscle asymmetry is the cause.

2. It's hard to imagine that building muscle can overcome the pathology that causes wedging when we see that even bracing hasn't been shown to work, whether in a growing child or for an adult spine.

[Dingo]

muscle imbalance

Pooka1

You are incorrect. Trunk muscles should not have a strong and weak side.

2000 - Study/Report: A Preliminary Report On The Effect Of Measured Strength Training In Adolescent Idiotpathic Scoliosis

...there is a consistent asymmetry in torso rotation strength that can be shown with specific strength testing and with myolectric activity. This is definitely abnormal.

2007 - Study:: Trunk rotational strength asymmetry in adolescents with idiopathic scoliosis: an observational study

The AIS females were found to be significantly weaker when contracting toward their main curve concavity in the neutral and concave pre-rotated positions compared to contractions toward the convexity. These weaknesses were also demonstrated when compared to the group of healthy female adolescent controls.

Several other studies have examined this well known phenomenon.

[Pooka1]

Pooka1

You are incorrect. Trunk muscles should not have a strong and weak side.

You need to audit a few hundred riding lessons. The only people who are very even are the upper level riders who worked DILIGENTLY at it for YEARS.

Some people are so one-sided who DON'T have scoliosis that I feel we can rule out muscle imbalance on that evidence alone. Some of these people actually LAMED their horses from their one-sided riding. I can point you to a web site of folks who diagnose and fix these horses if you don't believe me.

It's the rule rather than the exception and a big reason why most people never make it to the upper levels in riding in my opinion after doing the auditing.

When you are at the point where you are so one-sided you can lame a horse and you STILL don't have scoliosis, then we need to move on to a new hypothesis in my book. YMMV

[Pooka1]

Dingo, are you trying to say that muscle asymmetry is the CAUSE of AIS or an effect?

[Dingo]

asymmetry in healthy children

Pooka1

Did any of them measure the asymmetry in folks WITHOUT scoliosis?

Yes, the 2007 study compared healthy girls to girls with Scoliosis. As expected the difference between the two groups was large.

[Pooka1]

Pooka1



Yes, the 2007 study compared healthy girls to girls with Scoliosis. As expected the difference between the two groups was large.

Yes but that is due to the curve. And they didn't find that the kids with AIS were symmetrical. Unless people drawn to riding happen to be atypical, there are very few people who are symmetrical. If they were, we would see far more people making it out of the lower levels.

Is muscle asymmetry the cause or effect of scoliosis in your opinion?

[Dingo]

cause of effect

Pooka1

Dingo, are you trying to say that muscle asymmetry is the CAUSE of AIS or an effect?

AIS is rooted in a nervous system disorder.
2004 - Study: Melatonin Signaling Dysfunction in Adolescent Idiopathic Scoliosis

For reasons that aren't yet fully understood this impacts the muscles of the torso.
2006 - Study: Geometric and electromyographic assessments in the evaluation of curve progression in idiopathic scoliosis.

I believe this muscle imbalance is a significant factor in the development of spinal curves.

Secondary evidence:

It is well known that child atheletes have high rates of mild scoliosis. This is thought to be the result of muscle imbalances developed from long hours of training.
1986 - Study: Scoliosis in swimmers.

As you know three studies (study 1) found that strength training controls scoliosis progression and can even reverse many curves. This suggests that the muscles of the spine play a critical role in the development of Scoliosis.

[MissEmmyF]

Well two things...

1. I suggest there are any number of folks who appear to think the muscle asymmetry is the cause.

2. It's hard to imagine that building muscle can overcome the pathology that causes wedging when we see that even bracing hasn't been shown to work, whether in a growing child or for an adult spine.

I tend to disagree with them then. I don't think it's the cause. I can see how it could be a cause in some special cases though (just not in AIS most likely).

For example, at the advertising agency where I work, our proofreader has one fake arm/hand (since she always wears long sleeves, I'm not exactly sure how much of her arm is actually there, if any of it). So, her other arm/hand obviously does all the work while the other side just kind of remains motionless and in relaxation mode. She is def. developing slight thoracic scoliosis due to this...it's clearly apparent. This would seem to have developed only because of her muscles imbalances (i.e. the arm/hand she uses has become very strong overtime whereas the other side is probably very weak).

Also, my cousin got into a big skateboarding accident when he was 10 and was in a huge waist/leg cast for a long time. Now he's in his 30's and one of his legs is at least an inch or two longer than the other. It's so obvious that when he standing flat on one foot, the other foot only reaches the floor on its tip toe. He doesn't wear a lift in his shoe because the lift would have to be too big (and therefore wouldn't be able to be put in the shoe but would have to be put on the outside instead), so that means he walks around all day being totally off balance. I can't imagine that he won't develop at least slight scoliosis at some point in time due to this.

So, I do think muscle asymmetry can be the cause of scoliosis in some specific instances...just not for the vast majority of people with AIS.

[MissEmmyF]

but then again, i do think that most people have muscle imbalances...most people do have a strong side and a weak side. and, many people with large imbalances probably never develop scoliosis. i just think the strong side and weak side in people with scoliosis is way more severe and obvious than it is with the average person.

[Dingo]

MissEmmyF

So, I do think muscle asymmetry can be the cause of scoliosis in some specific instances

From what I have read I don't think a child can get severe scoliosis from a muscle imbalance. I remember reading that something like 80% of competitive javelin throwers have curves of roughly 10 degrees +/-. However these guys aren't getting their spines fused at 40 and 50 degrees.

AIS is rooted in a nervous system disorder. Maybe when the nervous system is messed up the body doesn't know how to correct or respond to muscle imbalances. Somehow the two are working together.

[MissEmmyF]

Pooka1



AIS is rooted in a nervous system disorder.
2004 - Study: Melatonin Signaling Dysfunction in Adolescent Idiopathic Scoliosis

For reasons that aren't yet fully understood this impacts the muscles of the torso.
2006 - Study: Geometric and electromyographic assessments in the evaluation of curve progression in idiopathic scoliosis.

I believe this muscle imbalance is a significant factor in the development of spinal curves.

Secondary evidence:

It is well known that child atheletes have high rates of mild scoliosis. This is thought to be the result of muscle imbalances developed from long hours of training.
1986 - Study: Scoliosis in swimmers.

As you know three studies (study 1) found that strength training controls scoliosis progression and can even reverse many curves. This suggests that the muscles of the spine play a critical role in the development of Scoliosis.

I think we're all kind of saying the same thing. So, you think the nervous system disorder is the "initiating" factor for the onset of the dev. of scoliosis. however, the muscles are then affected after the onset, correct?

[Dingo]

AIS nervous system

MissEmmyF

I think we're all kind of saying the same thing. So, you think the nervous system disorder is the "initiating" factor for the onset of the dev. of scoliosis. however, the muscles are then affected after the onset, correct?

Yes AIS appears to be caused by a nervous system disorder. An FDA approved blood test is due out as soon as this year to detect the disorder even before a curve develops.

Pharmeceuticals are being developed to control this nervous system disorder.

Researchers are also experimenting with Tamoxifen to control Scoliosis.

Obviously physical therapy is a preferable treatment for most parents but drug therapies are on the horizon.

[LindaRacine]

I remember reading that something like 80% of competitive javelin throwers have curves of roughly 10 degrees +/-.

What about the other 20%?

If muscle imbalance causes scoliosis, why isn't it 100%? I have a niece who had special xrays taken of her legs, to measure the bones in her legs. Her leg length discrepancy is 1-1/2", but she has a completely straight spine.

--Linda