VIBRATION TRAINING

Sasha,
Do you studies show any difference in increased motor unit recruitment due to greater proprioception stimulation with vertical uniform devices that have greater X and Y axis displacements (DKN and Physio Plate) as compared to devices that have manly Z axis displacement (VG Evolution)?

Personally I believe that there is not that great difference. If there's a horizontal minimal component, in depth and in left-right, the message to the receptors, may be slightly confused... in nature you have a great recruitment when walking on a perfectly flat pavement or on a bumpy one. Really don't know. It seem secondary aspect.

I was talking this morning with a WBV trainer customer of mine (10 years experience with Galileo) about the vertical pure or mixed with lateral forces. He is convinced the better is a pure vertical component.

I am strongly convinced that the main concept is the G force on the vertical plane, you can have 20 G on a horizontal movement but you won't get any muscle contraction... zero work.

The EMG shows clearly there is increased work only when you receive a vertical movement with enough strength to activate the neuromuscular reflex.
The greater G force, the greater EMG values.

If you hit the knee tendons too low with the hammer you have no effect... this factor, if you stay in a stand up position on the plate, can be excited only by a vertical movement, but it works even if the moment isn't perfectly perpendicular to the ground, like when you perform a deep 90° squat, hanging the handlebar, or when you run: when you hit the ground the moment is toward you, not perpendicular to the ground, and if you are running in circles? the moment is with a later moment component... so, I think the resulting Gforce has a predominant rule. The direction does matter but is of less importance, at least following this logic...

Further discussion kindly accpted!

Hi Sasha,

I have a similar opinion and I think you are correct in your discussion.

I have been working with vertical platforms in a research capacity and within clinical settings. Some of our recent data suggests that at lower frequencies, muscle activity within the upper body muscles may not increase significantly during proximal stimulation. I have only speculated that while performing pushups and similar postures, parallel muscle fibers to a vertical exercise platform are insufficiently stimulated to evoke an involuntary contraction.

One of our current research initiatives however is to examine different muscle groups via fine wire and tungsten electrodes. I have read a lot of the current literature and I have yet to see any research actually evaluating motor unit recruitment. Surface EMG is only a measure of global muscle activity that can be confounded by a variety of different limitations including the inherent noise found in vibration platforms. We have observed that when evaluating surface EMG, at any given frequency i.e. 45 Hz there will be a large spike in the power spectrum at that particular frequency as well as 90, 135 etc.. I have only read 2 or 3 studies that have accounted for this.

With that being said, I agree that the lateral displacement of a triaxial platform is so subtle that it may not exhibit changes in muscle activity outside of what we have observed with vertical platforms. However, it would be interesting to see but I still believe that understanding recruitment thresholds, firing rates etc.. is one of the most obvious research avenues that has been overlooked.

If you have the opportunity, you should take a look at http://www.wavexercise.com. This is the platform used in our studies and I'm interested in your feedback/thoughts. Thanks,

Jonathan

Hi Jonathan,
I took a brief look at the site you suggested. Very interesting!

The display functions of the vibration platform are really impressive. Is that the prototype or the production final release? I saw the true images on the about page. The brochure is heavy and I try to download with no success.
Want to know more about the platform, such magnitude (real one with load) and G force at various frequency if you can provide.

Hi Sasha,

This is the new model that was launched late last year.

We are currently working with an ergonomist and biomechanist that are evaluating all of the parameters that you're interested in. Much to my dismay, they don't like to share their findings until they have interpreted their results and performed all necessary tests! What I can tell you is that the WAVE Pro Elite operates between 20 - 50 Hz at either ~ 2 or ~ 4 mm and with the calibration system, I have been told that all parameters remain consistent up to a tested load of 500 lbs.

When we have more information, I'd be happy to share it with you. Our other research initiatives include bone mineral density, circulating stem cells, age related changes in muscle and bone morphology and stroke recovery. We are working with different institutions across North America (we're a Canadian company) and the only problem with research is the time it takes to become published!

Physics is normally quite boring for the average person, but I promise to make this relatively short and interesting. Who knows you may even find yourself repeating this to other people.

Ok to understand the basic physics behind creating a clean powerful vibration I am going to take you to the beach. What has that got to do with Vibration Training you say. Well actually most of the basic rules surrounding vibration can be observed at the beach. We are after all dealing with waves of energy.

Now there are 3 basic wave patterns.....

(1) Single Fq ......

This can be thought of a just a single wave traveling across the ocean in the form of a swell. It is often not known that multiple swells traveling at different speeds are moving across the ocean at any one time.

(2) Constructive Interference .....

This is where two waves roll over the top of each other in perfect unison, creating one larger and more powerful wave. On a beach you can see this in the form of a "surfers wave". Locals will even know if this is going to be every 5th or 7th wave depending on the beaches "math's"

(3) Destructive Interference .......

On a beach this can be seen in the form of a rip, it is essentially a "dead spot" where the waves come from different angles and appear to cancel each other out. I say appear because this is not the case. As we all know energy can not be created or destroyed, so where does it go if not into the formation of a wave ? The energy is in fact forced below the waters surface and it becomes turbulent like a washing machine. An important point to envisage when thinking about the destructive forces of waves.









So how does this equate to a Vibration Training machine......... ?

A machine using a single motor is just a single Fq . Easy to design, produce and understand. It is the simplest equation to have to deal with, as you are not dealing with multiple sources of energy. It is also cheaper to build. But of course this comes at a cost, less lineal direction and clean vibration.

Using 2 motors is preferred by most companies only because it allows the chance for a "constructive interference" to be produced. But if this is done wrong, the 2 motors create a "destructive interference" and causes all kinds of problems. These are some of the kinds of problems it can cause.....

(1) Overheating motors ( like bending a steel rod in half, the bend gets very hot, this release of energy is enough to create a lot of heat, enough to cook a motor or expend its bearings and chew them up )

(2) Cracked steel ( that washing machine analogy was not a joke, and it can actually break up the structural integrity of the steel )

(3) Unbalanced vibration ( this is where the machine makes a kind of whirr-whirr noise, it means the motors are running at different speeds. They will match speeds for a second and go quite, then go back out of sync and make a deep whirring noise )

Note: Companies like Vibro-Gym spent a fortune on creating an electronics system to keep the motors in sync for this very reason, and anyone who has used an older Pro unit of theirs will attest to the fact they can go unbalanced on occasion. Especially if a larger person stood on the machine lop-sided. Power Plates used to go unbalanced with no-one on them ??

(4) Excess noise Basically the reverberation can ring the machine like a bell. This kind of noise will almost be deafening and can drive you crazy, even if it does not seem very loud.

(5) Dead spots on the machine This manifests itself in areas where there seems to be almost no vibration. Funny enough this is where the steel is most likely to crack. Just like that rip on the beach, it is all very deceptive.

These issues become expediential the more power you want to produce, and with it room for error almost disappears. For this reason I believe most companies will keep using small motors or in some cases only 1 large motor. The consequences of "pretending" to understand the physics could end up being a warranty trap the company may not survive.