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TomB wrote:

Re: iPhone. I would not strap it to the head. All that would show is vibrations transmitted to the head, which are of limited interest, given that we already have PMID 24081617 telling us how to attenuate any possible damage by posture.

 

Potential damage to the head from doing daily handstand on the vibration platform is what I'm interested in at the moment -- since that is what I've been doing (for only a minute or so per day). I don't think the available papers address that body position. Bending the knees isn't likely to reduce transmission of the vibration to the head. Bending the arms might do so -- but would reduce the benefit that I'm expecting to get from the handstand position.

 

Dean, I don't have an answer to your question about how to interpret the G-force. Your proposed tests seem reasonable to me.

 

Todd

Edited by Todd S

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Dean,

 

If you haven't already picked an app, take a look at VibSensor, by Now Instruments and Software, Inc. I think it's available on Android as well as IOS. It's free until you want to enable emailing of results.

 

I've tried VibSensor only very briefly -- with a low vibration speed -- by setting my iPhone 6plus (on a piece of foam) -- on my Soloflex platform, on the Vibe Plate in 'soft' mode, and on the Vibe Plate in 'strong' mode.

 

In the Vibe Plate 'strong' mode test, the "Peak raw" dispay of the Z-axis value showed "LIMIT" -- which means "data occurred that was outside the measurement range of the accelerometer".

 

This may mean that a different accelerometer would be needed to directly measure the Vibe Plate in 'strong' mode. For example, the $799 "Digiducer 333D01" supports measurement of amplitude up to 20 g.

 

But the phone built-in accelerometer may be sufficient for measuring vibrations on the head, for example -- where the g's are presumably much lower than directly on the vibration platform.

 

Thanks,

Todd

Edited by Todd S

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Whole Body Vibration Plate Experimental Results

 

All,

 

You've got questions, I've got (very interesting) answers... Hold tight folks, it's going to be a bumpy ride. Sorry, I couldn't resist that one. ☺.

 

I decided to use the Android App called Accelerometer Analyzer, available for free in the Google Play store. The nice thing is it's easy to export data files it writes in CSV format to DropBox for easy import into Excel.

 

For my first test, I put my phone face down on the vibration plate and stood on it in sneakers, as illustrated in this photo:

 

UZ9MY38.png

 

I put fully half my weight on it to ensure that the plate, phone and my leg were well-coupled, just as if I were standing directly on the plate.

 

Then I did a series of measurements with the App in which I varied the both the intensity/amplitude (soft vs. strong) and the frequency (setting 10 vs. setting 20, which is supposed to be 23Hz vs. 42 Hz vibration frequency).

 

In the interesting of keeping this short, I'm going to only show one graph, and show the rest of these results in a table. Here is a link to the full spreadsheet with all the data and graphs for each condition for anyone who wants to see the details (they are each on a different sheet of the Excel document).

 

The graph is of the most vigorous vibration setting - strong intensity with at the maximum frequency. It shows the three axes of acceleration, measured in G's. If standing normally on the machine, the X Axis represents Left/Right, Y Axis  represents Forward/Backward, and the Z Axis represents Up/Down.

 

LxRcfk2.png

 

 

First, by counting the peaks, it's apparent that the frequency on the highest setting (20) is 33Hz, rather than the 42Hz indicated in the manual that came with the machine. I found this 33Hz quite consistently in all my tests on the highest frequency setting when combined with the Strong amplitude setting. Conversely, as you'll see from the table below, at the middle frequency setting (i.e. 10), the measured frequency actually slightly exceeded the frequency in the spec (26Hz vs. 23Hz). Looked at another way, there appears to be much less difference in frequency between the middle and the highest frequency settings than the manual indicates.

 

Next, let's look at the acceleration. From the graph you can see the Z-axis (up/down) shows the strongest acceleration (not surprisingly), but the Y-axis (forward/backward) also has a significant amount. In fact, across all my tests these two axes had significant acceleration associated with them, with the Y acceleration fairly constant and the Z acceleration varying a lot, while the X-axis (side-to-side) had very little. I surmise from this that the plate shakes in two directions - up/down and forward/backward, with up/down being primary.

 

Regarding the magnitudes - as you can see the peak acceleration in the up/down (Z) direction on the highest & fastest setting was about a little over 2G (~20m/sec2) in the up direction, and a little under -2G in the down direction. If we assume going from -2G to +2G represents a 4G total acceleration, we get about 4G's of acceleration in the Z direction. Taking the vector sum of the three axes (with estimated peak-to-peak excursions of 0.2G in X, 1.5G in Y, and 4G in Z, we get a total acceleration of 4.3G at the highest & fastest (i.e. most violent) setting at the surface of the vibration plate. That 4.3G is probably the most important number in this whole post. Tom, that's the one you care about, right?

 

Note - I verified that the accelerometer in my phone doesn't clip or max-out at 2 or 2.5Gs (single direction). When I really whip it through the air fast, I can get an accelerometer reading of 3.2Gs or higher. So there isn't any ceiling effect going on in the graph above.

 

I did this same sort of analysis for all four combinations of amplitude (soft vs. strong) and speeds (10 vs. 20). Here is the table representing frequency and total acceleration at the vibration plate in all four conditions:

 

f1VRQYP.png

 

As you can see, the lower right box of the table is the 33Hz & 4.3G discussed above for the Strong/20 combination. The other combinations are correspondingly lower. Interestingly, the Soft/20 combination results in a higher total acceleration than the Strong/10 setting.

 

 

 For my next set of tricks, er, experiments, I bit down on my phone, and stood in 3 different postures with the machine set on it's highest (most violent) setting (Strong/20), to see what the acceleration at my jaw/head looks like. Here are pictures of my three postures, straight-legged (left), small bend in the knee (middle), and large bend in the knee (right). You can see my orange phone clamped down between my teeth. I tried to keep the phone as level as possible between my teeth. Please don't make fun of my build, my skinny legs or my posture. I made the pictures intentionally small to mask all that...

 

 

6s55PNQ.png?1

 

I won't share any the graphs on this set of tests - but graphs similar to the one above are in the Excel file linked above if you're interested. Instead I'll just show the table of frequencies and accelerations for the three different postures when the plate is set to the highest settings (Strong/20)":

 

KWDIxb1.png

 

As you can see, moving from the plate to my head/jaw greatly attenuates the resulting acceleration - by almost an order of magnitude. Recall on the Strong/20 setting, the acceleration at the plate was 4.3G, while at my jaw/head it was only 0.48G, even when I was standing up straight. Slightly bending my knees (middle picture) cut acceleration at my jaw/head down by more than 50% again, down to 0.21G. A deeper knee bend brought it down a bit further to 0.16G.

 

So what's the verdict or upshot of all this analysis? I'm not convinced the higher frequency, small amplitude data in ISO-2631 has much basis in actual observed risk of damage. Tom I'll be curious to see what you dig up in that regard. But for now the ISO-2361 standard is the best info we've got to go on. By far the most intelligible representation of the vibration recommendations embodied in ISO-2631 that I've seen is the graph below from [1], showing contour lines for various acceptable duration of vibration as a function of frequency (X-axis) and amplitude/Acceleration (Y-axis).

 

 

9JzomMG.png

 

 

You'll notice I've added extra circles (in green and blue) to the graph above. The four green circles represent the vibration intensity at the plate of our machine, at the two intensities and two frequencies documented above. The three blue circles represent vibration at my jaw/head at Strong/20 while standing in the three different postures, as documented above. The locations of the circles are as best as I can estimate based on eyeballing the axes. As you can see, the vibration intensities at the plate is right along the border of "safe for 1 min exposure" and the vibrations at the jaw/head (where most of Tom & other's concerns seem to be focused), is well within the tolerable range for extended exposure (almost 8 hours), even with straight, stiff legs (top blue circle).

 

Based on this data, since I only stand on the plate for a two minutes a couple times a day, and at various knee bend postures, I consider it pretty safe. The nice thing is that our plate (on Strong/20 or Soft/20) seems both right at the top of the safe range (at least for relatively brief exposures) and also right around the spot in frequency / amplitude space which has been shown effective for bone building, as I detailed in the first post. That is it appears to occupy the "sweet spot" in the trade-off between benefits and risks.

 

It would be nice of someone (Todd? TomB?) could replicate my results using your own phone, posture, body shape/size, and perhaps a slightly different protocol, etc. But given this data as it stands, I'm pretty confident that the vibration plate isn't going to harm me, at least as I'm using it now. Your mileage may vary. In particular, I make no guarantees nor would I want to speculate about the safety of doing handstands, splits or other acrobatics on model of vibration plate we share. You'll have to determine that for yourselves.

 

--Dean

 

-------

[1]  J Sci Med Sport. 2013 Nov;16(6):526-31. doi: 10.1016/j.jsams.2013.01.004. Epub

2013 Mar 1.
 
Safety and severity of accelerations delivered from whole body vibration exercise
devices to standing adults.
 
Muir J(1), Kiel DP, Rubin CT.
 
Author information: 
(1)Department of Biomedical Engineering, Stony Brook University, USA.
 
 
OBJECTIVES: Whole body vibration devices are used as a means to augment training,
and their potential to treat a range of musculoskeletal diseases and injuries is 
now being considered. The goal of this work is to determine the degree to which
acceleration delivered by whole body vibration devices at the plantar surfaces of
a standing human is transmitted through the axial and appendicular skeleton, and 
how this mechanical challenge corresponds to the safety threshold limit values
established by the International Standards Organization ISO-2631.
DESIGN: Non-blinded laboratory assessment of a range of whole body vibration
devices as it pertains to acceleration transmission to healthy volunteers.
METHODS: Using skin and bite-bar mounted accelerometers, transmissibility to the 
tibia and cranium was determined in six healthy adults standing on a programmable
whole body vibration device as a function of frequency and intensity. Measures of
transmissibility were then made from three distinct types of whole body vibration
platforms, which delivered a 50-fold range of peak-to-peak acceleration
intensities (0.3-15.1 gp-p; where 1g is Earth's gravitational field).
RESULTS: For a given frequency, transmissibility was independent of intensity
when below 1g. Transmissibility declined non-linearly with increasing frequency. 
Depending on the whole body vibration device, vibration ranged from levels
considered safe by ISO-2631 for up to 8h each day (0.3 gp-p @ 30 Hz), to levels
that were seven times higher than what is considered a safe threshold for even 1 
min of exposure each day (15.1 gp-p @ 30 Hz). Transmissibility to the cranium was
markedly attenuated by the degree of flexion in the knees.
CONCLUSIONS: Vibration can have adverse effects on a number of physiologic
systems. This work indicates that readily accessible whole body vibration devices
markedly exceed ISO guidelines for safety, and extreme caution must be practiced 
when considering their use.
 
Copyright © 2013 Sports Medicine Australia. Published by Elsevier Ltd. All rights
reserved.
 
PMCID: PMC3688642
PMID: 23453990

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Dean,

 

I ran just the first set of four measurements comparable to what you did. Instead of looking at displayed "Peak raw" values (which sometimes showed "LIMIT" for the Z axis) as I previously did in my first look at the app the other day, I this time just eyeballed the charts (like i think you did) to very roughly estimate top to bottom excursion numbers for X/Y/Z. Then I used a vector magnitude calculator to get a single number.

 

Soft 10

Resonance 30 Hz

X 0.1G

Y 2.7G

Z 2.7G

Magnitude 3.8

 

Soft 20

Resonance 43 Hz

X 0.0

Y 2.1

Z 3.1

Magnitude 3.7

 

Strong 10

Resonance 26 Hz

X 0.4

Y 2.0

Z 5.4

Magnitude 5.8

 

Strong 20

Resonance 38 Hz

X 0.5

Y 5.0

Z 2.0

Magnitude 5.4

 

So, compared to your

 25/1.3  36/3.2

 38/3.6  33/4.3

 

I got

 30/3.8  26/5.8

 43/3.7  38/5.4

 

We used different phone hardware/software. And there might be some difference in our vibration plates.

 

Perhaps you might consider trying the VibSensor app to see what kind of results you get with it. [The Accelerometer Analyzer app that you used doesn't appear to be available for IOS.] It would be interesting to see if you at least get the same frequency values using two different apps. If not, it might indicate that one or both apps have an insufficient sampling rate to accurately determine the frequency.

 

Todd

Edited by Todd S

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Todd,

 

Thanks for replicating my experiments! Given the crude nature of our methods and the differences in equipment and circumstances, I'm impressed with the agreement of our results. You got somewhat higher amplitude of acceleration across the conditions than I did. I'll try to repeat at least a couple of my experiments with the Android version of the VibSensor App you used (on your iPhone) later today.

 

I know iPhone glass tends to shatter :-), but I wonder if you would be willing to try the "bite test" I did to see if you can verify the dramatic attenuation of vibration at the jaw/head when standing on the vibration plate with straight legs or with knees slightly bent. That seems like a pretty critical thing to know about for safety's sake.

 

Of course if you're really feeling bold, you could try biting your phone while doing one of your handstands on the vibration plate! I'm curious how that pose influences the magnitude of jaw/head vibration.

 

--Dean

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Whole Body Vibration Plate Experimental Results - Round 2

 

Todd,

 

Thanks for the recommendation to try the VibSensor App. It is pretty cool. But at least on android you've got to pay $5 to be able to upload the raw data off the phone - something I'm loath to do. So we'll just have to make due with screen captures...

 

I replicated my first experiment, where I stood on my phone with the platform set to it's highest setting (Strong/20) using the VibSensor App. Here is the screenshot of the VibSensor data:

 

1XRuKXq.png

 

The first thing to notice is the resonant frequencies. All three axes were resonating at 33Hz, exactly what I measured yesterday in the same condition with the Accelerometer Analyzer App I was using. So there is good agreement there.

 

Next look at the amplitude of the vibrations of the three axes in the graph. Towards the right side of the graph, where things have stabilized most, it appears the Z-axis (blue) ranges from around +22 m/s2 to -16m/s2 for a peak-to-peak range of ~38m/s2. Since 1G = 9.8m/s2, that is a vibration magnitude of 3.9G in the Z (up/down) axis. Similarly, Y appears to have an peak-to-peak excursion of about ~27m/s2, or ~2.7G. X vibration looks like around 0.75G peak-to-peak. The vector sum of the three vibrations gives us 4.8G.

 

Interestingly, that is almost exactly ½ way between my measurement yesterday in the same conditions using the same phone and the Accelerometer Analyzer App (4.3G) and your measurement with your iPhone in the same conditions using the VibSensor App (5.4G). 

 

The second experiment I tried was to take my phone out of it's rubberized case - which I thought could be dampening the vibration. I tested it in the same conditions - i.e. standing on it with the vibration plate set to Strong/20. Here is the screen capture from a representative sample of data from that run:

 

P45pyld.png

 

Again we see 33Hz - the case apparently wasn't altering the frequency of the vibration. As for the amplitude, it looks a bit higher to me, particularly in the Y axis. But if anything, this tells me the vibration magnitude experienced by my feet is likely to be lower than any of these phone-against-plate readings, since (unlike barefoot Sthira), I always stand on the plate wearing somewhat-shock-absorbing socks and minimalist running shoes, which together will certainly dampen the vibration more than my phone case.

 

I've added your data points (4 pink squares) and my new data point (light green circle) to my frequency/amplitude plot from yesterday:

 

lZSs1Zm.png

 

 

It looks like we're getting a pretty tight cluster in the neighborhood of the yellow-to-red border. Given that my shoes and socks cushion the vibration at my feet, and the acceleration is greatly attenuated by the time it reaches my (all-important ☺) head (blue circles), I continue to be unconcerned about damage or injury from my short (2min) bouts of standing on our vibration platform.

 

What do you think Todd (or others)? Had a chance to try the standing bite test or the handstand bite test I suggested?

 

--Dean

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Dean,

 


Thanks for the recommendation to try the VibSensor App. It is pretty cool. But at least on android you've got to pay $5 to be able to upload the raw data off the phone - something I'm loath to do. So we'll just have to make due with screen captures...


I know iPhone glass tends to shatter :-), but I wonder if you would be willing to try the "bite test" I did to see if you can verify the dramatic attenuation of vibration at the jaw/head when standing on the vibration plate with straight legs or with knees slightly bent. That seems like a pretty critical thing to know about for safety's sake.

 

Of course if you're really feeling bold, you could try biting your phone while doing one of your handstands on the vibration plate! I'm curious how that pose influences the magnitude of jaw/head vibration.

 

I don't have any need to upload the raw data off the phone, especially since I'm just eyeballing the waveforms for rough data. My phone screen seems big enough for this purpose.

 

My original plan was to run ten tests:  the first seven to correspond to your seven tests and an additional three while inverted (supported with feet back touching shelving) -- (a.  arms slightly bent and shoulders slightly "planched"; b.  arms straight and shoulders stacked over hands like in a proper handstand; and c.  arms straight but upper chest pushed out to be slightly "bridged")).

 

But after doing the first four tests (phone in contact with vibration plate surface) -- and comparing the results to yours, I decided to defer the rest of the tests until I better understood whether the results I was getting made sense. I thought that there were too many differences between our results.

 

Thank you for repeating one of your tests with the VibSensor App. Since you got the same Resonance frequency as with your other App, it gives me some confidence in continuing with the tools that I have. I still don't know if the Magnitude values that I'm seeing are valid, since the App in some cases reports "LIMIT" (as I explained in an earlier post). That appears to be a limitation of the accelerometer on my phone.

 

Dean, did you ever see "LIMIT" in the "Peak raw" data with your phone?

 

It occurs to me that the measured Resonance frequency is likely to be dependent on the mass of the user resting on the vibration plate. Since our body weights differ significantly, that might account for some of the differences in results.

 

I also think that the measured Magnitude when putting phone in contact with vibration plate surface might be dependent on exactly where the phone is placed. I'm not certain that I sufficiently controlled this variable.

 

Experiments to determine the influence of these factors might be appropriate before moving on to the more exotic tests like with inversion. [i may not get to this until next weekend.]

 

By the way, it occurs to me that for an inversion test if the phone is upside down between the teeth then the tongue is on top when inverted -- and so it could be used to click a touch-screen button. [Yes, the tongue can click a button.] That thought was just a meager attempt at humor, since the VibSensor App lets you set a Delay before the measurement starts anyway. [Thus far, I've been using a Delay of 15 seconds and a Measurement duration of 10 seconds.]

 

[in case you didn't discover it, on the VibSensor results display you can click on X, Y, or Z buttons to toggle their waveforms off/on so that you easily view a single waveform. Note also that you can use settings to have the display in g's.]]

 

-----

 

I find it interesting that PMCID PMC3688642 covers a lot about transmissibility results from measurements, but doesn't include those data points in figure 2. It seems that doing so would significantly reduce impact of the warnings.

 

Todd

Edited by Todd S

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Todd,
 

Dean, did you ever see "LIMIT" in the "Peak raw" data with your phone?

 

Yes. In fact if you look at my two screen captures from the VibSensor App display in my post above, you'll see several instances where the App reports "LIMIT" for Y and/or Z axis acceleration. I also see the same thing (Z LIMIT reported) when I collect data dropping my phone from 1" off the table. Since I'm pretty sure it's not experiencing more than 1G of acceleration during that short fall due to gravity, I discount this as an artifact of either the accelerometer or the App.

 

On the topic of VibSensor artifacts and shortcomings (besides the inability to upload data w/o paying), I notice from the VibSensor display that the data rate it is collecting at is only 101.5Hz, which is only half the rate of data acquisition that I get using my other app, Acceleration Analyzer (AA). Between this slower acquisition rate and its limited zoom capability (max 5x), it's no wonder that the waveforms I see on the VibSensor display look so thin, spiky and close together, compared with the graphs I made of the data from the AA App.

 

The one advantage I see for the VibSensor App over the AA App (besides being available across platforms) is that you can review the recorded data on the phone itself. This is useful, despite its rather crude display and limited zoom capability. While the AA App shows a live graphical display of accelerations, you can't freeze it to eyeball the data carefully. Instead you've got to upload the data to a program like Excel to dig into the details, which gives it more flexibility and power, but is nevertheless a pain.

 

I look forward to your report on your other experiments - particularly the bite tests.

 

--Dean

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Dean,

 

I was planning to do addional tests at speed setting 20, but I think that the results here for speed setting 10 are probably sufficient for now. I did a slightly different set of tests than I originally planned. All tests were done with either the feet or the hands at the edges of the vibration plate. With the phone on the plate, it was located slighty inward to avoid bumps and thus only half under the right foot. Straight legs if upright. Straight arms if inverted. Thin yoga socks and thin workout gloves. For 'bite' measurements, the phone was sandwiched between two old CDs for protection of the phone. I used 20 second Delay and 20 second Duration.

 

s10p+30  30/4.8     X 0.0   Y 2.2   Z 4.3   Soft 10  plate  upright  +30pounds

s10p        30/4.8     X 0.0   Y 1.2   Z 4.6   Soft 10  plate  upright

s10u        30/0.33   X 0.13 Y 0.03 Z 0.30 Soft 10  bite    upright

s10i         30/0.38   X 0.01 Y 0.03 Z 0.38 Soft 10  bite    inverted

 

h10p+30  27/5.1     X 0.2   Y 1.0   Z 5.0   Strong 10  plate  upright  +30pounds

h10p        26/7.8     X 0.3   Y 0.8   Z 7.8   Strong 10  plate  upright

h10u        26/0.84   X 0.10 Y 0.03 Z 0.83 Strong 10  bite    upright

h10i         28/0.87   X 0.23 Y 0.03 Z 0.84 Strong 10  bite    inverted

 

In support of what you reported, vibration at the jaw appeared to be about an order of magnitude less than at the vibration plate. This was true whether upright or inverted. There was very slightly higher transmission to the jaw when inverted than when upright.

 

[The "+30pounds' test didn't show much difference in these results with Speed 10. In an initial 'Soft 10 plate...' run that I had subsequently deleted the data for, the frequency was slightly less with the extra weight. I don't think I calculated Magnitude for that run.]

 

The Magnitudes at the plate (upright) appear somewhat higher here than with my earlier report:

 

   Earlier: 30/3.8 26/5.8

   Here:    30.4.8 26/7.8

 

I think that that difference is because here the feet were in thin yoga socks and positioned at the edges of the vibration plate, whereas earlier the feet were in athletic shoes and were positioned inside of the bumps on the vibration plate.

 

Todd

Edited by Todd S

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Todd,

 

That is a great set of additional experiments. Thanks for doing them. It is interesting to see the vibration frequencies you got in this set of experiments was lower than in you initial tests, and more in line with what I've observed. Any thoughts as to why this might be the case?

 

Regarding the magnitude and its implications. That 26Hz / 7.8G reading your got standing upright on the plate set to Strong/20 is getting pretty deep into the red "unsafe for even 1min" (red region) of the graph I included above. What are your thoughts about this and your other test results? Have they altered the way to intend to use the vibration plate?

 

From my perspective, based on the data both of us have collected, I intent to keep using the plate on stong/20 most of the time, but:

  • Keep session short (~2min)
  • Always wear shocking absorbers - i.e. socks and sneakers if upright, gloves if I try inverted poses
  • Keep my feet (or hands) away from the extreme outer edges of the plate where acceleration is highest
  • Keep my knees (or arms if inverted) slightly bent most of the time, with only brief periods of straight legs/arms

Are these lessons consistent with your observations and intended future practices? It is good to see the attenuation is consistent at the jaw/head whether upright or inverted. Do you interpret this as a green light for inverted use of the platform, or does that level of acceleration on your hands concern you (e.g. risk of neuropathy)?

 

Do you have other takeaway messages from your (or my) data?

 

--Dean

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Since Tom is away, I'll channel him in regard to concern over vibration-base neuropathy of the hands.

 

Study [1] found dental hygienists exposed to vibration through their instruments had higher rates or neuropathy, muscle weakness and desensitization to the detection of vibrations at all frequencies, especially in their dominant hand, compared to controls who didn't use dental instruments. But then again, their instruments vibrate at 6000-40,000 Hz, and they use their tools for hours each day, so that study probably isn't too relevant.

 

Much more relevant, and disconcerting as a result, are studies of forestry workers who use chainsaws. There is a mountain of evidence these (mostly) men suffer neuropathy quite frequently due to the vibration of their saws. Here is a link to a pubmed search with 20 studies supporting this association - and that's just the first page.

 

So how much do chainsaws vibrate? Hand tool manufacturer Husqvarna has this handy vibration calculator, allowing you to pick any one of their tools and get its vibration characteristics (in m/s2) and compute a daily exposure based on hours of use. It will even tell you whether your exposure across all the tools you use puts you in the green, yellow or red zone for total daily vibration, based on a widely-used tolerable vibration metric called A(8), described here

 

Playing around with the calculator, it looks like chainsaws generate between 0.3 and 1G of acceleration on one's hands/arms. Using a chainsaw that delivers a 0.3G vibration for 8h / day puts you just into the red - i.e. too much vibration exposure for safety according to Husqvarna's calculator.

 

As you might imagine, a chainsaw delivers vibration in many different frequencies, with a peak around 200, at least according to the figure below, taken from a report [2] by human factors researchers who did a study of forestry equipment for the UK equivalent of OSHA. The acceleration chainsaws deliver in the frequencies our plate delivers (30-40Hz) looks to be around 0.2G. But the real power is up around 200Hz, where the acceleration is about 5G. Given that our plate delivers ~5G at a lower frequency, our plate is definitely more dangerous regarding hand vibration than a chainsaw, if used for hours per day...

 

gDsG5ZN.png

I'm not sure what all of this tells us, except sustained hand/arm vibration lower than or perhaps in the neighborhood of what one experiences with hands on our vibration plate is well-documented to cause neuropathy in folks who operate a chainsaw for a living. Of course these lumberjacks spend at least several hours a day actively holding their saws, so it may not be a fair or valid comparison with the relatively brief exposures that we are doing, or contemplating doing.

 

Nevertheless, as Tom says, we should first do no harm. Unless someone can convince me it's safe and beneficial to use our vibration plate in "hands on" mode - I think I'm going to be conservative and stick with standing poses myself, for very brief sessions, (mostly) bent knees and with cushioned shoes.

 

As for the straddling side splits and other "up close and personal" poses it sounds like Sthira and (maybe) Todd S have experimented with, I'm going to give those a wide berth. I certainly don't want to risk neuropathy in that part of my anatomy!

 

--Dean

 

----------

[1] Occup Environ Med. 1995 Feb;52(2):116-23.

 
Neuropathy in female dental personnel exposed to high frequency vibrations.
 
Akesson I(1), Lundborg G, Horstmann V, Skerfving S.
 
Author information: 
(1)Department of Occupational and Environmental Medicine, University Hospital,
Lund, Sweden.
 
 
OBJECTIVE: To evaluate early neuropathy in dental personnel exposed to high
frequency vibrations.
METHODS: 30 dentists and 30 dental hygienists who used low and high speed hand
pieces and ultrasonic scalers were studied, and 30 dental assistants and 30
medical nurses not exposed to vibration (all women). Vibrotactile sensibility,
strength, motor performance, sensorineural symptoms and signs, and vascular
symptoms in the hands, as well as mercury concentrations in biological samples
and cervicobrachial symptoms, were studied.
RESULTS: The two groups exposed to vibration had significant impairments of
vibrotactile sensibility, strength, and motor performance, as well as more
frequent sensorineural symptoms. In the dentists there were significant
associations between the vibrotactile sensibility and strength, motor
performance, superficial sensibility, and sensorineural symptoms. There were no
associations between these findings and cervicobrachial symptoms, mercury
concentrations, or smoking. There was no increase of vascular symptoms of the
hands in the groups exposed to vibration.
CONCLUSION: Dental hygienists and dentists had a slight neuropathy, which may be 
associated with their exposure to high frequency vibrations, and which may be
detrimental to their work performance. Thus, development of safer equipment is
urgent.
 
PMCID: PMC1128165
PMID: 7757164
 
----------
[2] Hand-arm vibration emission of chainsaws – comparison with vibration exposure. 
 

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Dean,

 

It is interesting to see the vibration frequencies you got in this set of experiments was lower than in you initial tests, and more in line with what I've observed. Any thoughts as to why this might be the case?

 

I think you misread my post. My inital and later tests did not differ in the reported resonant frequencies. In both sets of tests, the "Soft 10" setting resulted in 30 Hz -- and the "Strong 10" setting resulted in 26 Hz. For the later set of tests, I didn't didn't use a speed of 20 at all. I wrote, "I was planning to do additional tests at speed setting 20, but I think that the results here for speed setting 10 are probably sufficient for now."

 

That 26Hz / 7.8G reading your got standing upright on the plate set to Strong/20 is getting pretty deep into the red "unsafe for even 1min" (red region) of the graph I included above.

 

This was identified as "Strong 10", not "Strong 20".

h10p        26/7.8     X 0.3   Y 0.8   Z 7.8   Strong 10  plate  upright

 

I'm still not certain about the accuracy of the Magnitude values. And we haven't run enough experiments yet to determine consistency of the reported results.

 

And remember that PMC 3688642 said, "This recommendation is mainly based on exposures in the range of 4 h to 8 h...". It seems to me that this is probably mostly due to occupational exposure. The same source also says "“Shorter durations should be treated with extreme caution.” But is there evidence of problems with shorter durations?

 

What are your thoughts about this and your other test results? Have they altered the way to intend to use the vibration plate?

 

As I've described before, I'm currently just using the vibration plate for about a one minute supported handstand every morning -- using the "Strong 10" setting -- and periodically moving between slightly planched, proper stacked handstand, and slightly bridged. I use "Strong 10" not because "Strong 20" is difficult or dangerous, but because the latter is less convenient. Before kicking up (quite vertically because of space limitations) into a handstand, the unloaded vibration plate on "Strong 20" is very noisy and jumping around so much that it doesn't always stay in place. For this reason, "Strong 10" seems more convenient. I intend to continue this usage for now.

 

As I've also described before, I hang from my ankles for about a minute before moving to the vibration plate to do the morning handstand. While hanging upside down, I for about 5 seconds at a time alternate hands using one hand to stretch the fingers and wrist back at 90 degrees on the other hand. This is to prep my wrist for the subsequent handstand.

 

I haven't yet started spending upright time on the vibration plate, but I intend to do so -- maybe at some other time of the day. I'll probably use the "Strong 20" setting, since bodyweight on the vibration platform eliminates the noise and hopping around issues that are present with an unloaded plate. The reason I plan to spend upright time on the vibration plate in the future is because it is far more likely (than when inverted) to stimulate the hip bones. I want to use straight legs when upright because I want the maximum transmission of vibration to the hips (as also noted below).

 

From my perspective, based on the data both of us have collected, I intent to keep using the plate on stong/20 most of the time, but:

  • Keep session short (~2min)
  • Always wear shocking absorbers - i.e. socks and sneakers if upright, gloves if I try inverted poses
  • Keep my feet (or hands) away from the extreme outer edges of the plate where acceleration is highest
  • Keep my knees (or arms if inverted) slightly bent most of the time, with only brief periods of straight legs/arms

Are these lessons consistent with your observations and intended future practices? It is good to see the attenuation is consistent at the jaw/head whether upright or inverted. Do you interpret this as a green light for inverted use of the platform, or does that level of acceleration on your hands concern you (e.g. risk of neuropathy)?

 

 

I'm only using the vibration plate in order to get the presumed benefits of vibration on the body. But using shock absorbers, staying away from the outer edges of the plate, and bending the limbs -- all reduce the transmission of the vibration to the body -- and I don't see the need for them myself at this point. For example, I want to use straight legs when upright because I want the maximum transmission of vibration to the hips. If you want less vibration on the body, it seems that you could just use a lower speed setting and/or the Soft mode instead of the Strong mode. [i currently use thin workout gloves on the vibration plate only because the surface seems somewhat smooth and I don't want my hands to unintentionally slip.]

 

The main thing I was initially concerned about was transmission of excess vibration to the brain. With the experience that we have so far -- of order of magnitude less vibration being transmitted to the jaw -- I'm not currently concerned about it. And I'm not planning to ever do a headstand on the vibration plate.

 

With regard to your question about the hands, I'm not currently concerned. I haven't experienced any problem thus far. I should point out that in the gym as part of my warmup I spend a significant amount of time doing both stretching and strengthening exercises for the hands and wrists. [i got these routines from the Handstand One course from gymnasticbodies.com] I have "small bones" (inherited from my Mother, I think) -- and I consider it very important to always work on maintaining or improving wrist mobility and strength.

 

Todd

Edited by Todd S

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Todd S.,

 

I think you misread my post. My initial and later tests did not differ in the reported resonant frequencies. In both sets of tests, the "Soft 10" setting resulted in 30 Hz -- and the "Strong 10" setting resulted in 26 Hz. 

 

You are right - sorry about that.

 

h10p        26/7.8     X 0.3   Y 0.8   Z 7.8   Strong 10  plate  upright

 

Interesting. That 7.8G vibration intensity at the plate on the Strong/10 setting seems pretty high. I'd be curious what you get if you repeated the upright Strong/20 test in the same conditions (standing near edge of plate in socks rather than shoes). Subjectively, it feels to me like Strong/20 gives me a much more vigorous "shake" than Strong/10, but your previous data didn't seem to support that subjective impression - the acceleration at Strong/10 seemed as high (or higher) than Strong/20.

 

The reason I plan to spend upright time on the vibration plate in the future is because it is far more likely (than when inverted) to stimulate the hip bones.

 

That's my primary objective for using the vibration plate as well - bone building of my hips and spine.

 

I'm only using the vibration plate in order to get the presumed benefits of vibration on the body. But using shock absorbers, staying away from the outer edges of the plate, and bending the limbs -- all reduce the transmission of the vibration to the body -- and I don't see the need for them myself at this point.

 

It seems like a delicate balance between too little vibration to be effective for bone building and too much to be safe according to the ISO standard. I agree that the ISO standard seems to be based on data that we're either unaware of or that doesn't exist. But you'd think it has got to be based on something, and according to ISO, the vibration level you're reporting is in the "red" zone - unsafe for even a minute of exposure, which seems troubling on the face of it.

 

Perhaps when Tom returns he can share what he's learned about the potential hazards of vibration.

 

--Dean

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It looks like I will never catch up with this thread given all the other open threads to respond to, so my apologies if I've missed some point that I was expected to address - I'll try my best. Update on ISO - I've emailed the head of the secretariat of the technical committee responsible for the maintenance and development of the the ISO-2631(TC 108/SC 4) Ulrich Schober asking for a pointer to the materials on which the standards were developed - so far, crickets. So until I hear back, I'm a bit stymied wrt. PMC3688642.

 

Pressing on, there are any number of papers where various concerns wrt. WBV might transpire, but often there is no full free text available and so it's hard to evaluate: for example, PMID: 27061448 examines "Exaggerated haemodynamic and neural responses to involuntary contractions induced by whole-body vibration in normotensive obese versus lean women" - contrasting the effect in obese vs lean, but without the full text it's impossible to know if there was any abnormal response in lean women too (even if less than in obese). Papers dealing with occupational WBV injuries are hard to translate relevantly to therapeutic machines, though sometimes they have value in that at least they describe the range of possible injuries and concerns (f.ex. PMID: 26460379). Therefore, I have decided for now to move on from the "do no harm" aspect of WBV. Occasionally I mention (but don't discuss) papers that lack full free text just in case someone has access to the full text (f.ex. PMID: 27238625 ).

 

Dean asked about the math/physics and calibration modeling. There is actually a paper that addresses this question directly - PMID: 26740726 with full text available. 

 

The next step after "do no harm" is to identify possible benefits, and then optimal protocols. Many papers identifying various benefits specify protocols, although obviously not always globally, and there are papers that address the latter directly (which I will cite). Example: 

 

Balance - this is an important function given that humans increasingly lose balancing abilities as they age, and falls and broken bones are strongly associated with mortality. WBV seems like a good therapy - PMID: 26035724 doesn't have a free full text, but the abstract has enough data to be useful. But the real star is this wonderful paper: PMID: 26844514 - with full free text available - it examines directly a practice that I already engage in (and I think Dean does too?) - balancing without visual input (closed eyes), and it found strong benefits of balancing on WBV platforms with eyes closed as opposed to eyes open - this is a fantastic modality of strengthening this vital function through the use of our machines. Additionally, balancing without visual feedback strengthened knee muscles more. And finally the ultimate test - in a 6 month follow up there were 0% hospital visits (due to falls) from the WBV balancers as opposed to almost 30% of the controls having to visit the hospital due to falls. Bottom line: this is the best evidence that WBV can help avoid falls and strengthen knee muscles (especially blind balancing). This benefit alone strikes me as sufficient justification for engaging in WBV therapy as we age and worry about our bones, muscles, falls and balancing. I highly recommend reading this paper (they even reference Tai-Chi!) for the protocol and consider incorporating it in your practice (if feasible in your situation). Btw. this is the machine they were using: X-Trend Commercial Grade Vibration Machine LV-1000 (link: http://www.x-trendfitness.com.tw/s/en/2/product/Commercial-Grade-Vibration-Machine-LV-1000-195607.html) .

 

[more]

Edited by TomBAvoider

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In addition to bone health, muscle strength and balance, there are possible WBV benefits wrt. middle age (and elderly) arterial stiffness - PMID: 24872684 - anti-infammatory status of elderly PMID: 26253933 and even improved cognitive performance in both young healthy and ADHD individuals: PMID: 24587412 and PMID: 24949870 . 

 

The balance benefits are not limited to the elderly, but happen in the younger healthy adults PMID: 24520362, and in training enhancing both balance and muscle endurance PMID: 24587114 . If you have muscle strength imbalances (say, in your legs), WBV can be very helpful: PMID: 26406063.

 

Before focusing on developing a global protocol, it's important to note that "subjects of different weights could be receiving different vibrations": PMID: 25148418 - therefore measuring your body on your platform is a key variable to control. Fortunately, it seems commercially available smartphone and the like devices should be adequate - here is a study showing the 5th generation of the iPod Touch used to measure vibration (the iPod Touch is basically a low-level iPhone): PMID: 25106947

 

[more]

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Thanks Tom and welcome back!

 

Regarding WBV and balance - yes, I do practice closing my eyes and doing (slow) squats on the vibration plate to improve my balance. I'm not sure about others, but I find it quite helpful and somewhat challenging. Something about the vibration makes balancing a challenge, at least for me. BTW, I've also been practicing your ritual of balancing on one leg with bent knee while brushing my teeth. This too is helping with balance I believe, although I still can't do it with my eyes shut for any length of time.

 

Regarding full texts of interesting papers - here is one [1] you requested:

 

http://www.tandfonline.com.sci-hub.cc/doi/full/10.1080/14763141.2016.1171894

 

It basically confirmed what Todd and I have already observed with our smartphone accelerometer tests (which you should read if you haven't had a chance yet). Namely that vibration is greatly attenuated as you move up the body, away from the plate, and that joint angles make a big different for vibration transmissivity.

 

Perhaps the most important observation was about the ankle vibration:

 

The values of resonance peaks are summarised in Table 1. In the ankle, a resonance peak
is observed at a frequency of 44 Hz. At that frequency, the transmissibility is at a maximum,
but this is not the only frequency that represents amplification in this joint. In almost all the
frequencies studied, the measured acceleration in the ankle is higher than the input acceleration.
Thus, if the vibration exposure is assessed according to the input acceleration, such
assessment would underestimate the real vibration dose received by the ankle. It is important
to highlight that the increase in this acceleration can lead to joint damage (Carlsoo, 1982).
 
...
 
In this work, whether the case is static or dynamic condition, the dose of vibration suggests
that the ankle joint has higher exposure and then a higher risk of possible joint damage
and cartilage degeneration than the other studied joints. This result appears to agree with
those previously reported (Bressel et al., 2010; Harazin & Grzesik, 1998; Kiiski et al., 2008).
 
...
 
As the purpose of this work was to evaluate the response of the lower limb, no footwear
was use. However, the presence of shoes could add a variation in the response determined in
this study mostly due to the dampening of the shoe material. This fact should be considered
during WBV training and the practical applications of this work.

 

I haven't looked at those references about vibration-induced ankle injury, but this seems like more reason to me to keep wearing shoes and socks when I use the vibration platform...

 

--Dean

 

----------

[1] Sports Biomech. 2016 May 30:1-20. [Epub ahead of print]

Transmission of whole body vibration to the lower body in static and dynamic
half-squat exercises.

Munera M(1), Bertucci W(1), Duc S(1), Chiementin X(1).

Author information:
(1)a Research Group in Engineer's Sciences (GRESPI), Faculty of Exact and Natural
Sciences , University of Reims Champagne-Ardenne , Reims , France.

 

Full text: http://www.tandfonline.com.sci-hub.cc/doi/full/10.1080/14763141.2016.1171894

Whole body vibration (WBV) is used as a training method but its physical risk is
not yet clear. Hence, the aim of this study is to assess the exposure to WBV by a
measure of acceleration at the lower limb under dynamic and static postural
conditions. The hypothesis of this paper is that this assessment is influenced by
the frequency, position, and movement of the body. Fifteen healthy males are
exposed to vertical sinusoidal vibration at different frequencies (20-60 Hz),
while adopting three different static postures (knee extension angle: 180°, 120°
and 90°) or performing a dynamic half-squat exercise. Accelerations at input
source and at three joints of the lower limb (ankle, knee, and hip) are measured
using skin-mounted accelerometers. Acceleration values (g) in static conditions
show a decrease in the vibrational dose when it is measured at a more proximal
location in the lower extremity. The results of the performed statistical test
show statistically significant differences (p < 0.05) in the transmissibility
values caused by the frequency, the position, and to the presence of the movement
and its direction at the different conditions. The results confirm the initial
hypothesis and justify the importance of a vibration assessment in dynamic
conditions.

PMID: 27238625

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Thank you Dean, for the full text of PMID: 27238625, and it indeed rewards study by anyone who is interested in the subject of possible joint damage while using WBV machines. They do also reference ISO-2631, but again, until I hear back, the supporting materials remain opaque. As to PMID: 15676450, the abstract is not useful, but this is another “review of the literature”, which simply means it’s a pointer further down the rabbit hole that needs those studies to be chased down in turn.

 

My takeaway from PMID: 27238625 is that ankles are the joint that’s at greatest exposure to dangerous levels of g forces (another study shows 10 fold greater impact on ankles compared to knees and hips - PMID: 19523867), so wearing shoes should alleviate that. One concern with wearing shoes is that in trying to identify optimal protocols for whatever end points one desires (f.ex. balance, bone health, muscle, arterial stiffness etc.) I’m relying on studies that most often use subjects without shoes. Therefore whatever target ranges those forces were specified in those protocols, cannot simply be dialed in on our machines, and instead must be adjusted through measurement while wearing shoes.

 

I have not come across studies showing WBV damage in ankle joints specifically. The studies that I have seen deal with soft tissue in the ankle area (muscles and ligature) and ankle injuries such as sprains - so for example in PMID: 18218826 WBV was found to strengthen foot muscles in healthy elderly subjects, and PMID: 21072738 found WBV used in a therapeutic setting helped dancers with injured ankles achieve better ankle stability.

 

PMID: 18348698 identifies various dangers of WBV for the musculoskeletal system. The subjects did not wear shoes. Sessions of 10 minutes per day were seen as allowing the strengthening of the skeleton, while remaining safe. And yet again, it seems straightened knees postures should be avoided.

 

But back to developing protocols. There seems to be something of a consensus that the best posture from a safety point of view is one with bent knees - at least when it comes to protecting the head. However, while this clearly attenuates any vibration to the head, I wondered if there was a way to get vibration benefits to the arms. It appears possible and this is explored directly in PMC4708876: “This study revealed that a crouching position on a WBV platform with direct contact between the knees and elbows was effective for conducting vibration from the lower to the upper extremities.”

 

Neuromuscular and cardiovascular effects of WBV appear to attenuate after the first day of exposure - PMID: 24905721 - which may indicate that for such effects to be evoked repeatedly, it is not useful to do WBV on a daily basis, but rather adopt a protocol that seems to strongly benefit muscle development - PMID: 24832971. There may be interesting data about targeting specific muscles in the full text of PMID: 23000688 which I don’t have access to. Similarly, for exercises on the WBV platform using weights there is PMID: 24719045, the abstract identifies optimal muscle loading, but without the full text it’s of limited usefulness.

 

For arterial stiffness WBV benefits protocol: PMID: 18462269.

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Tom,

 

That is another great set of studies you've dug up for helping to zero in on a most effective WBV protocol. I'd be very happy to be proven wrong about ankle injury risk and the wisdom of wearing shoes. Sthira will be happy too with the positive results observed for WBV's ability to help repair dancers' injured ankles. 

 

I will note however that not all of your studies appear to be done barefoot, as it sounds like you were suggesting. The images in PMC4708876 (the study about using direct contact between knees and elbows to maximize upper body transmission) show a subject squatting in what are clearly well-cushioned running sneakers. 

 

There are so many moving parts (pun intended) when it comes to WBV protocol, I'll be curious to see what conclusions you come to about how to maximize the benefits of our WBV platform.

 

How are you using yours now? Or are you staying off it until you've figured all this out?

 

--Dean

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I'm staying off the platform until I figure out how best to use it without injuring myself or working at cross-purposes. I've only been using it briefly for various simple experiments, as I read the various papers. It's slow going due to time constraints (I've still not managed to even finish my "fiber and HH" response, let alone respond to your trenchant responses!), and I fully understand why MR is a rare presence here - the choice being to either be sloppily short in ones posting (which results in misunderstandings as I see in the fiber/HH thread), or endlessly delayed responses and multiple open threads demanding interaction. I wish I was retired and could devote more time to all this... life-prolonging research consumes far more time than I could ever hope to gain back as a result of all this research (which is why the only saving grace is if you enjoy such research, which I fortunately do). Meanwhile it's looking like another crazy week at work. All I can do is apologize for how long all this is taking. 

 

A brief note on the constraint criteria for developing protocols: I'm focusing mostly on studies relevant to people similar to my wife and myself (40's to 60's age group, white, generally healthy, low BMI, exercisers, etc.) - not out of lack of generosity, but simply lack of time; I'd rather do a comprehensive survey, then do a sloppy job of covering too much too shallowly. So no studies in animals, severely injured (spine, burn victims etc.), morbidly obese, children, elite athletes, diabetics, stroke, arthritis etc.

 

And again, I sometimes cite studies that have an interesting abstract, but I can't incorporate into any protocol building due to lack of free full texts - so if anyone has access to the full papers feel free to post :)... example from this morning: PMID: 26173589 plus this, perhaps of special interest to Dean  :PxyzPMID: 22562741

 

Re: many moving parts. Yes - and protocols that are good for X often are counter to Y, so ultimately, how one uses the machine will depend on your goals of the moment - example from this morning (with full text): PMID: 22947546

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TomB,

 

Sorry you don't have the time others of us do to obsess most of the day over the details of a healthy diet and lifestyle ☺. And sorry to keep you so busy on this and the other hot threads. No hurry. I and the rest of our crazy bunch seem content to (semi-)blindly forge ahead with use of the WBV platform, figuring you'll eventually figure out what we're doing wrong, and trusting we won't have trashed our bodies too badly in the meantime. As I said, no hurry ☺.

 

I want to say again - I really appreciate you digging up all these fascinating papers showing benefits of WBV. I especially liked the one about the benefits of WBV for the bone health of well-trained cyclists - which I'll cite in full [1] for others to see and for future search purposes. Perhaps not surprisingly, given how thin cyclists are and their general lack of high-impact exercise, cyclists tend to have low bone mineral density. So the authors of [1] wanted to see if WBV therapy would help. From the full text of [1], here was the WBV protocol they used for the cyclists (my emphasis):

 

The vibration [cyclist] group performed 15 min of intermittent vibration training 3 times per week for 10 weeks in conjunction with their normal cycling training. The vibration was performed on calibrated, vertical synchronous vibrating plates (DKN XG 5.0, DKN Technology, California, USA)... All vibration training was performed at a frequency of 30 Hz (which is the frequency often used for bone loading as it causes the greatest muscle activation and therefore possibly greater osteogenic response from bones [ 8 ] ), and amplitude of 3 mm, with the 15 min consisting of 10 sets of 60 s of vibration and 30 s of rest. An intermittent protocol was used to stimulate greater osteogenic responses due to the constant stimulus to the mechanoreceptors [ref] . In order to maximize the vibration effect and standardize the procedure, subjects were taught the correct posture (standing barefoot on the vibrating plates to diminish dampening effects, with knees slightly bent to avoid vibration to the head, holding firmly onto the handlebars and placing most pressure on the heel of the foot).

 

It looks like another example of barefoot, knees-bent posture with vibration parameters most similar to our plate's "Strong/20" setting, based on Todd and my accelerometer measurements. Maybe barefoot is a good idea after all...

 

Here were the details of their impressive results:

 

After 10 weeks of training, vibrating cyclists showed a significantly greater increase in hip bone 
mineral density (0.020±0.010 g.cm - 2 (1.65%), p=0.024) while the control
cyclists ( - 0.004±0.001 g.cm - 2 (0%)) showed no change (p>0.050). The control
group had a significantly lower spine bone mineral density (1.027±0.140 g.cm - 2,
p=0.020) compared to baseline (1.039±0.140 g.cm - 2). This loss was not observed 
in the vibrating group. 10 weeks of whole body vibration training increased hip
and preserved spine bone mineral density in road cyclists.
 

Here are the graphs of BMD comparing the cyclists who underwent 10 week of vibration therapy along with their normal training (VIB) compared to cyclists who just did their normal training without vibration therapy (CON):

 

qvzedmP.png

 

Wow - that is probably the most impressive results I've seen to date showing WBV therapy benefits bone health after only 10 weeks. And these were relatively lean (BMI ~24), healthy, in-shape (10h/wk training), middle aged (~44 years old) men - demographically reasonably similar to many of us.

 

Thanks for digging that one up Tom. It's a keeper. One other thing - you keep asking for full texts. I presume when you ask that you've already tried and not been successful getting the full-texts via sci-hub.cc. Am I right in that assumption?

 

Keep up the good work here on the forums and on your job too, he says begrudgingly...

 

--Dean

 

----------

[1] Int J Sports Med. 2012 Aug;33(8):593-9. doi: 10.1055/s-0032-1301886. Epub 2012

May 4.
 
Whole body vibration increases hip bone mineral density in road cyclists.
 
Prioreschi A(1), Oosthuyse T, Avidon I, McVeigh J.
 
Author information: 
(1)Exercise Laboratory, School of Physiology, Faculty of Health Science,
University of the Witwatersrand, Johannesburg, South Africa.
alessandra.prioreschi@wits.ac.za
 
 
This study aimed to determine the effects of 10 weeks of whole body vibration
training on the bone density of well-trained road cyclists. 15 road cyclists were
assigned to either a vibrating group (n=8), who undertook 15 min of intermittent 
whole body vibration at 30 Hz, 3 times per week while continuing with their
normal cycling training; or a control group (n=7), who continued with their
normal cycling training for the 10-week period. Cyclists were age, body mass and 
height matched with 15 sedentary participants. At baseline, all participants
underwent regional dual x-ray absorptiometry scans, where both cycling groups had
lower pelvic (p<0.050) and higher head bone mineral density (p<0.050) than the
sedentary participants with no other differences observed. After 10 weeks of
training, vibrating cyclists showed a significantly greater increase in hip bone 
mineral density (0.020±0.010 g.cm - 2 (1.65%), p=0.024) while the control
cyclists ( - 0.004±0.001 g.cm - 2 (0%)) showed no change (p>0.050). The control
group had a significantly lower spine bone mineral density (1.027±0.140 g.cm - 2,
p=0.020) compared to baseline (1.039±0.140 g.cm - 2). This loss was not observed 
in the vibrating group. 10 weeks of whole body vibration training increased hip
and preserved spine bone mineral density in road cyclists.
 
© Georg Thieme Verlag KG Stuttgart · New York.
 

PMID: 22562741

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This is a longshot, but if anyone runs across anything about mountain biking please post it. That's still one of my favorite activities, and does make the arms and legs absorb pretty high vibrational load (depending on how rough a trail you ride on).

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I presume when you ask that you've already tried and not been successful getting the full-texts via sci-hub.cc. Am I right in that assumption?

 

Yes, that is correct, sci-hub.cc rarely works for me, perhaps one out of ten searches - though perhaps I’m doing something wrong! I use the DOI number string for searches. The majority of my searches find nothing. Going back - the last 3 I tried, examples of papers which came up empty on sci-hub: PMID: 25251250 PMID: 24806038 PMID: 20980923 .

 

I’ve even installed the Sci-Hub extension on my Chrome.

 

Now, back to ISO-2631, still crickets. Which is a pity, because I keep coming across studies that make safety references to ISO-2631 (f.ex. PMID: 17909407) - and it’s worth noting that continuous index refinements are made, like ISO-2631-1:1997 to ISO-2631-5:2004 (PMID:23558167).

 

However, safety seems to be pretty well covered, and the precautions outlined so far (bent knees, no excess time without shoes etc.) seem adequate barring new information I have so far not come across. Regarding concern about the spine, given the large age-related changes such as curvature, disc thinning or degeneration etc. bone vulnerability of CR’d folks (I think even some CRONies reported reduced height), there is this pretty comprehensive review, which should put to rest any concerns over the impact of WBV on the spine, as long as basic safety practices are observed: PMC3940795 - from the conclusion: “The average peak force on a VBR increases by approximately 24 % during WBV compared to the same posture without vibration. The maximum force during WBV is mostly less than that for walking. Therefore, the magnitude of the force during WBV should not be harmful, even for people with osteoporosis. Bending the knees or standing on the forefeet leads to lower force increases relative to standing with straight legs.” Along the same line (i.e. vibration stress compared to walking and jogging) for the femur PMID: 21480091. The very principle of WBV impact on bone formation and its safety is given experimental foundation in PMID: 20190375

 

Exploring, at great length, the development of WBV protocols, one must reach the inescapable - and quite understandable - conclusion, that no one protocol is going to result in all the potential benefits of WBV. Instead, every identified benefit will have its own protocol, and therefore one should approach WBV from the point of view of tailoring a set of goals to one’s own situation. That would include age, sex, and any possible morbidities (which I have excluded in my searches), as well as individual weight. Given the variability of such optimal protocols for various goals, I have personally settled on identifying a series of goals and then using protocols for the different goals at different times. So, for example, I intend to use the machine for strengthening balancing abilities pretty much on an ongoing basis, but also adopt additional protocols for periods of months in the interest of hip-bone building, or a different protocol - again for a limited period of time - for strengthening knee muscles and tendons and so on. 

 

In the interest of developing those various protocols, I have identified studies which seem to have sufficient evidence of benefits and clear protocols that are applicable to our situation (i.e. for example that deal with vertical vibration movement, and not split-side vibrations which are not possible on our machines etc.). This way, instead of just presenting protocols ex cathedra, everyone can examine the studies themselves to check my work so to speak, and anyone can tailor their own goals and adjust based on the studies. A nice overview of the protocols/benefits as we know them are to be found in full text of PMID: 18762281, and PMID: 20541297 (one of the rare times for which sci-hub worked). 

 

For musculo-tendinous goals, PMID: 27331044 provides a good overview with emphasis on the development of protocols with clinical applications for specific outcomes (some can be ignored, f.ex. “children” and you can pick f.ex. “elderly”): muscle training, muscle soreness, bone metabolism.

 

For Knee Extension and Knee Muscle strength: meta-analysis with protocols for older and younger - PMID: 23989260

 

For Hip BMD, leg muscle strength and balance in post-menopausal women - PMID: 15040822. Note, that this might apply to men just as much for all we know, and further, the easy protocol might be an inviting option for your spouse (since you already have the machine).

 

[to be continued]

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Now, back to ISO-2631, still crickets. Which is a pity, because I keep coming across studies that make safety references to ISO-2631 (f.ex. PMID: 17909407) - and it’s worth noting that continuous index refinements are made, like ISO-2631-1:1997 to ISO-2631-5:2004 (PMID:23558167).

 

Thank you, Tom. I've only had this little machine for about a month now, and backed off excessive use of it due to potential safety concerns. At first, before reading your writing and some of your linked studies, I was using it as an aid for increasing flexibility in some of my joints. Then I thought, well, this is crazy, I'm overdoing it (as usual...)

 

Now I'm using the machine infrequently, about once per week, at a setting of around 10, and for about 20 minutes at a time. These are completely arbitrary numbers -- I'm just doing what "feels good" and realize my anecdote is probably useless.

 

Also I'm not using the machine for any standing poses, like squats or bent-knee positions. Rather, I'm using it more as a restorative device, in a manner similar to this pose, which in yoga is viparita karani: https://en.m.wikipedia.org/wiki/Viparita_Karani

 

I put blankets on the machine, and simply lay my sacrum on the thing, extend my legs up the wall, relax, and like the feel of vibration. I report less lower back and hip pain, and this may or may not be placebo. Longer term sporadic use will guide me because as the link http://www.ncbi.nlm.nih.gov/m/pubmed/17909407/ you posted states:

 

"More research is needed to explore the long-term health hazards of WBVT."

 

I might use the machine at some point for the standing poses you're suggesting for balance, but for now that's not how I'm using it.

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Tom,

 

Thanks once again for you terrific digging into studies that can help us refine our WBV protocol. This continues to be a  tremendous help. 

 

...sci-hub.cc rarely works for me, perhaps one out of ten searches...

 

Hmmm... That is odd. I'd say for me I can get 75+% of the full texts I'm seeking from sci-hub if not available elsewhere. I too always search using the DOI. 

 

Regarding the three specific papers you had trouble getting:

 

Here is the first, via ResearchGate (I couldn't get it via sci-hub either).

Here is the second, via sci-hub (the pubmed DOI # was wrong).

Here is the third, as free full text from publisher's website.

 

However, safety seems to be pretty well covered, and the precautions outlined so far (bent knees, no excess time without shoes etc.) seem adequate barring new information I have so far not come across.

 

That is good to hear from your mouth Tom. I won't hold you to it (obviously), but it is comforting nonetheless.

 

The very principle of WBV impact on bone formation and its safety is given experimental foundation in PMID: 20190375.

 

That looks like a great one! I haven't yet read the free full text, but the abstract says very good and interesting things about the mechanism and effectiveness of WBV for bone health:

 

Current data indicate that the anabolic and anti-catabolic effects of whole body vibrations on the skeleton are unlikely to require muscular activity to become effective. Even high-frequency signals that induce bone matrix deformations of far less than five microstrain can promote bone formation in the absence of muscular activity. This independence of cells on large strains suggests that mechanical interventions can be designed that are both safe and effective.

 

... no one protocol is going to result in all the potential benefits of WBV.

 

That makes sense, unfortunately. 

 

I intend to use the machine for strengthening balancing abilities pretty much on an ongoing basis, but also adopt additional protocols for periods of months in the interest of hip-bone building, or a different protocol - again for a limited period of time - for strengthening knee muscles and tendons and so on. 

 

What - no interested in promoting brown adipose tissue? That was what got this whole thing started for me anyway. I wonder if Kenton is reading this thread. We've got him to thank for the machine we're all using - which I continue to be very impressed with, and using several times a day for short intervals - see my current protocol below.

 

My interests (in order of importance) are: bone building, balance, BAT promotion and muscle strengthening. The last is only last because I do so much else to build muscle strength.

 

Regarding taking what we learn from all these amazingly large # of studies to build protocols, since my #1 goal is ensuring bone health, I liked this one [1] you pointed to. Although as you indicate it was a study of postmenopausal women, the vibration group saw a dramatic improvement in hip BMD (+0.93%) relative to a sedentary control group (-0.62%) and a resistance training group (-0.60%). From the free full text, the vibration protocol used in [1] was:

 

Training frequency was three times a week, with at least 1 day of rest between two sessions...
 
The subjects in the WBV group performed static and dynamic knee-extensor exercises on the vibration platform (PowerPlate, Amsterdam. The Netherlands): squat, deep squat, wide stance squat, one-legged squat, and lunge. Training load was low at the beginning but progressed slowly according to the overload principle.(11) The training volume increased systematically over the 6-month training period by increasing the duration of one vibration session, the number of series of one exercise, or the number of different exercises. The training intensity was increased by shortening the rest periods or by increasing the amplitude (low, 1.7 mm; high, 2.5 mm) and/or the frequency (35–40 Hz) of the vibration. In addition, training load was increased by changing the execution form of the exercises from predominantly two-legged to one-legged exercises. The duration of the WBV program was a maximum of 30 minutes, which included warming up and cooling down.
 
The peak acceleration of the sinusoidal vibration stimulus—as recorded by an accelerometer (MTN 1800; Monitran, Bucks, UK)—varied between 2.28g and 5.09g (root mean square acceleration between 13.5 and 34.6 m/s2). Of the 5g acceleration, as measured on the platform, only a fraction is transmitted through the feet to the hip and spine. However, the exact degree of transmissibility is unknown. Bipolar surface EMGs (Myosystem 2000; Noraxon, Scottsdale, AZ, USA) recorded from m. rectus femoris and from m. gastrocnemius illustrate the impact of the vibration on muscle activity (Fig. 1). During the vibration training sessions, the subjects wore similar gymnastic shoes to standardize the damping of the vibration cause by foot wear.

 

Here are a few other impressive results from [1]:

 

Dynamic strength increased by 16.5% (95% CI, 9.4–23.5) and 10.6% (95% CI, 5.6-15.5) in the WBV group and RES [Resistance training] group, respectively (p < 0.001).

 

So the above protocol helped build leg muscle strength better than resistance training as well.

 

More on the bone benefit:

 

 Compared with the RES group, the 6-month vibration intervention resulted in a significant 1.51% net benefit in total hip BMD (p < 0.05). A similar net benefit (1.53%, p < 0.01) was observed in comparison with the CON group. The gain in total hip BMD in the WBV group was statistically unrelated to the increases in isometric or dynamic strength (r = −0.23, p = 0.29 and r = 0.28, p = 0.20, respectively).

 

It's interesting that bone benefits and strength benefits weren't strongly correlated in the women in the vibration group.

 

Finally, they didn't mention it in the abstract, but they also tested balance between the WBV and control group and found (modest) benefits on that metric as well:

 

The effects of WBV training on postural sway are summarized in Table 4. Postural sway (rms and peak-to-peak amplitude) during unperturbed stance with or without vision did not change because of WBV training (data not shown).After a fast, brief abduction of the arms, the peak-to-peak amplitude of sway in the anterior–posterior direction was significantly decreased during the WBV training (p < 0.05).Similarly, the peak-to-peak amplitude of sway in medio–lateral direction after a brief anteflexion of the arms was significantly decreased because of WBV training (p = 0.05). None of these variables changed across the 24 weeks in the CON group.

 

So the posture / balance benefits of their protocol wasn't huge, but then again, they didn't have subjects close there eyes.

 

The protocol in [1] was similar to the protocol I've been employing as of late, although mine usage is not (yet) quite so intense, extended in duration, or distributed over the week.

 

I've basically been standing on the plate 2-3 times per day for 2 minutes per session. I wear my minimalist running shoes without socks. I put the machine on the Strong/20 setting, which Todd and I found generates a vibration frequency and magnitude pretty much in the middle of the range that [1] employed: 35-40Hz and 2.28g to 5.09g, respectively.

 

While standing on the plate I do slow deep-knee squats - holding the pose at the bottom with knees bent at a little more than 90 degree angle for a couple seconds. I do a similar brief pause at the top of the exercise with pretty straight knees to momentarily maximize vibration through my lower body and up through my back.

 

In order to get balance training benefits as well, I keep my eyes closed for most of the 2min session. I hold onto the straps in case I lose my balance, but I'm finding I'm getting better with time regarding balancing on the plate.

 

So that's how I'm using our plate currently. I'm hoping based on [1] and other studies, that it will help with bone building, balance (since I'm closing my eyes while doing dynamic motions on the plate), and muscle strength. As a side benefit, I'm hoping this protocol will also boost BAT, but that hasn't been demonstrated in people yet, only in rats.

 

Sthira shared his protocol - thanks Sthira! Tom, Todd or anyone else, can you share your current protocols? I'm very curious how you guys are using it, and would be happy to get feedback from you on my protocol.

 

Finally, I'm really surprised why other CR folks who I know are concerned about bone health (Saul, Michael, Kenton) haven't popped in on this thread. I wonder if anyone but the small number (4-5) of us actively posting are actually taking notice of the strong evidence of benefits for WBV for bone health - which is something I think all CR practitioners should be cognizant of.

 

Thanks!

 

--Dean

 

-----------

[1] J Bone Miner Res. 2004 Mar;19(3):352-9. Epub 2003 Dec 22.

 
Effect of 6-month whole body vibration training on hip density, muscle strength, 
and postural control in postmenopausal women: a randomized controlled pilot
study.
 
Verschueren SM(1), Roelants M, Delecluse C, Swinnen S, Vanderschueren D, Boonen
S.
 
Author information: 
(1)Laboratory of Motor Control, Department of Kinesiology, Faculteit Lichamelijke
Opvoeding en Kinesitherapie, Katholieke Universiteit, Leuven, Belgium.
 
High-frequency mechanical strain seems to stimulate bone strength in animals. In 
this randomized controlled trial, hip BMD was measured in postmenopausal women
after a 24-week whole body vibration (WBV) training program. Vibration training
significantly increased BMD of the hip. These findings suggest that WBV training 
might be useful in the prevention of osteoporosis.INTRODUCTION: High-frequency
mechanical strain has been shown to stimulate bone strength in different animal
models. However, the effects of vibration exercise on the human skeleton have
rarely been studied. Particularly in postmenopausal women-who are most at risk of
developing osteoporosis-randomized controlled data on the safety and efficacy of 
vibration loading are lacking. The aim of this randomized controlled trial was to
assess the musculoskeletal effects of high-frequency loading by means of whole
body vibration (WBV) in postmenopausal women.
MATERIALS AND METHODS: Seventy volunteers (age, 58-74 years) were randomly
assigned to a whole body vibration training group (WBV, n = 25), a resistance
training group (RES, n = 22), or a control group (CON, n = 23). The WBV group and
the RES group trained three times weekly for 24 weeks. The WBV group performed
static and dynamic knee-extensor exercises on a vibration platform (35-40 Hz,
2.28-5.09g), which mechanically loaded the bone and evoked reflexive muscle
contractions. The RES group trained knee extensors by dynamic leg press and leg
extension exercises, increasing from low (20 RM) to high (8 RM) resistance. The
CON group did not participate in any training. Hip bone density was measured
using DXA at baseline and after the 6-month intervention. Isometric and dynamic
strength were measured by means of a motor-driven dynamometer. Data were analyzed
by means of repeated measures ANOVA.
RESULTS: No vibration-related side effects were observed. Vibration training
improved isometric and dynamic muscle strength (+15% and + 16%, respectively; p <
0.01) and also significantly increased BMD of the hip (+0.93%, p < 0.05). No
changes in hip BMD were observed in women participating in resistance training or
age-matched controls (-0.60% and -0.62%, respectively; not significant). Serum
markers of bone turnover did not change in any of the groups.
CONCLUSION: These findings suggest that WBV training may be a feasible and
effective way to modify well-recognized risk factors for falls and fractures in
older women and support the need for further human studies.
 
PMID: 15040822

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Thank you Dean - I should have realized that there were other options than sci-hub, so that was very helpful of you... and ouch, I didn't notice the DOI was corrupt, my bad.

 

Re: WBV and BAT - the studies that I've seen in humans reference body composition without breaking down adipose tissue into white/beige/brown, and seem geared to losing weight. The BAT studies in rats and mice are intriguing, but I have long since made a determination that in developing any health practice, I should rely as little as possible on animal data, as there are simply too many variables and problems with translating to humans. There are thousands of vibration studies out there, and if I am to have any hope of getting a decent set of protocols based on a reasonably thorough examination of the literature, I simply cannot read all the studies and must have criteria that restrict my search - otherwise it'll turn into another interminable research project with no end in sight. As I mentioned in a previous post, I have therefore narrowed my search criteria for WBV effects pretty drastically - the first cut was to exclude any studies that are exclusively in animals (although if a study is an overview of both human and animal data, I will still include it) - which is why BAT is not featured in my protocols. This doesn't mean that I am not interested in WBV and BAT, just that I don't believe I'll be able to develop a protocol for promoting BAT that's anything other than a complete WAG (Wild A$$ Guess). In the same vein, for purely practical reasons, I have excluded all studies that deal with children, stroke victims and WBV therapeutic applications for various morbidities that I don't happen to suffer from, elite sports, extreme frailty, obesity, bed-ridden etc. Again, not because of any lack of concern for anyone with those conditions, but simply due to lack of time, I had to make choices.

 

You mentioned in another thread - jokingly(?) - that I seem "conservative", possibly implying that perhaps I'm being over-cautious. In my defence, the explanation is pretty simple - if it were only about myself, I'm sure I'd take a lot more chances and "flyers", though hopefully never reckless - but I'm on the CR-cum-healthy lifestyle adventure not alone, but joined by my wife. She relies on my guiding our health-lifestyle choices, and so I feel acutely the responsibility and obligation to "first do no harm" to the best of my ability - this naturally leads to a much more conservative approach than would perhaps be my natural inclination. In the case of the WBV intervention, it has translated into an extra focus on safety simply because it is an intervention with a shorter track record and fewer already developed research protocols and outcome measures. If my safety focus seems somewhat alarmist, I apologize and hasten to add that by no means do I claim myself to be an authority on what is a reasonable approach for any given person - my "safety first" approach is guided by my and my spouse's circumstances foremost. I hope this disclaimer will alert anyone reading these posts to my own "conservative" bias.

 

I am not as yet done with the research, as unfortunately often times I must digest a study fully, before deciding that it does or does not merit inclusion in the pool of final consideration studies, and it's all sadly time-consuming given how many studies there are. 

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