Re: Muscle Activity During Stable and Unstable Squatting

[Guest guest]

ok... so the unstable squat didn't provide any more muscle stimulation despite

the claims if I read this correctly?

so why is this fad continuing to be used and sold as stimulating more muscle

rather than normal squats using more weight and other safe modalities? pretty

expensive to find 1 and train on it around here I've heard...

Just wondering.

the Phantom

aka Schaefer, CMT/RMT, competing powerlifter

Denver, Colorado, USA

Muscle Activity During Stable and Unstable Squatting

The below may be of interest:

Effect of Absolute and Relative Loading on Muscle Activity During Stable and

Unstable Squatting

IJSPP Volume 5, Issue 2, June

Original Investigations

Purpose: The purpose of this investigation was to determine the effect of stable

and unstable conditions on one repetition maximum strength and muscle activity

during dynamic squatting using absolute and relative loading. Methods: Ten

recreationally weight-trained males participated in this study (age = 24.1 ¡À

2.0 y, height = 178.0 ¡À 5.6 cm, body mass = 83.7 ¡À 13.4 kg, 1RM/body mass

= 1.53 ¡À 0.31), which involved two laboratory sessions separated by 1 wk.

Linear position transducers were used to track bar displacement while subjects

stood on a force plate for all trials. Vastus lateralis (VL), biceps femoris

(BF) and erector spinae (L1) muscle activity (average integrated EMG [iEMG]) was

also recorded during all trials. During the first session subjects complete a

one repetition maximum test in a stable dynamic squat (S1RM = 128.0 ¡À 31.4

kg) and an unstable dynamic squat (U1RM = 83.8 ¡À 17.3 kg) in a randomized

order with a 30-min rest period between conditions. The second session consisted

of the performance of three trials each for 12 different conditions (unstable

and stable squats using three different absolute loads [six conditions] and

unstable and stable squats using three different relative loads [six

conditions]).

Results: Results revealed a statistically significant difference between S1RM

and U1RM values (P ¡Ü .05). The stable trials resulted in the same or a

significantly higher value for VL, BF and L1 muscle activity in comparison with

the unstable trials for all twelve conditions.

Conclusions: Unstable squatting is of equal or less (depending on the loading

condition) benefit to improving or maximizing muscle activity during resistance

exercise.

==============

Carruthers

Wakefield, UK

[Guest guest]

,

Interesting abstract. I'm curious what the unstable squatting conditions

involved?

I'm also wondering what muscle activity (measured as IEMG) really tells us. Many

people misinterpret it as a proxy for force production - which does not seem to

be the case.

Regards,

Plisk

Excelsior Sports •Shelton CT

www.excelsiorsports.com

Prepare To Be A Champion!

________________________________

The below may be of interest:

Effect of Absolute and Relative Loading on Muscle Activity During Stable and

Unstable Squatting

IJSPP Volume 5, Issue 2, June

Original Investigations

Purpose: The purpose of this investigation was to determine the effect of stable

and unstable conditions on one repetition maximum strength and muscle activity

during dynamic squatting using absolute and relative loading. Methods: Ten

recreationally weight-trained males participated in this study (age = 24.1 ¡À

2.0 y, height = 178.0 ¡À 5.6 cm, body mass = 83.7 ¡À 13.4 kg, 1RM/body mass

=

1.53 ¡À 0.31), which involved two laboratory sessions separated by 1 wk.

Linear

position transducers were used to track bar displacement while subjects stood on

a force plate for all trials. Vastus lateralis (VL), biceps femoris (BF) and

erector spinae (L1) muscle activity (average integrated EMG [iEMG]) was also

recorded during all trials. During the first session subjects complete a one

repetition maximum test in a stable dynamic squat (S1RM = 128.0 ¡À 31.4 kg)

and

an unstable dynamic squat (U1RM = 83.8 ¡À 17.3 kg) in a randomized order with

a

30-min rest period between conditions. The second session consisted of the

performance of three trials each for 12 different conditions (unstable and

stable squats using three different absolute loads [six conditions] and unstable

and stable squats using three different relative loads [six conditions]) .

Results: Results revealed a statistically significant difference between S1RM

and U1RM values (P ¡Ü .05). The stable trials resulted in the same or a

significantly higher value for VL, BF and L1 muscle activity in comparison with

the unstable trials for all twelve conditions.

Conclusions: Unstable squatting is of equal or less (depending on the loading

condition) benefit to improving or maximizing muscle activity during resistance

exercise.

============ ==

Carruthers

Wakefield, UK

[Guest guest]

Relevant details:

" Instability was created during the squat by placing an inflated disc under each

foot.

With respect to variations in reports of muscle activity during stable and

unstable conditions it appears that the discrepancies, to a certain extent, can

be

explained by the use of absolute or relative loading. Data from the current

study

clearly shows that using absolute loading attenuates the differences observed in

muscle activity between stable and unstable trials. For example, Norwood et al8

reported significantly higher levels of trunk muscle activity during an unstable

bench press exercise but used absolute loading. The current investigation found

significantly higher L1 muscle activity in a stable squat in the eccentric phase

when using relative loading at 90% of maximal strength, but these differences

did

not exist during the absolute loading conditions. As explained above the

scientific

validity of isolating the effect of stability or instability independent of

intensity

requires the comparison based on relative and not absolute loading.

In conclusion, it appears that instability, whether comparing among absolute

or relative loading conditions, does not increase muscle activity of prime

movers

(VL, BF) or trunk musculature (L1). Furthermore, when appropriately comparing

stable and unstable trials using relative loading, muscle activity is actually

significantly

decreased as a result of instability. Therefore, it is concluded based on the

current data that using instability during exercises results in a diminished

capacity to

improve strength or function of the active musculature and is not recommended as

a

viable tool for exercise intervention in either healthy or injured subject

populations. "

-----------------------

Carruthers

Wakefield, UK

>

>

> The below may be of interest:

>

> Effect of Absolute and Relative Loading on Muscle Activity During Stable and

Unstable Squatting

>

> IJSPP Volume 5, Issue 2, June

> Original Investigations

>

> Purpose: The purpose of this investigation was to determine the effect of

stable and unstable conditions on one repetition maximum strength and muscle

activity during dynamic squatting using absolute and relative loading. Methods:

Ten recreationally weight-trained males participated in this study (age = 24.1

¡À 2.0 y, height = 178.0 ¡À 5.6 cm, body mass = 83.7 ¡À 13.4 kg, 1RM/body mass =

1.53 ¡À 0.31), which involved two laboratory sessions separated by 1 wk. Linear

position transducers were used to track bar displacement while subjects stood on

a force plate for all trials. Vastus lateralis (VL), biceps femoris (BF) and

erector spinae (L1) muscle activity (average integrated EMG [iEMG]) was also

recorded during all trials. During the first session subjects complete a one

repetition maximum test in a stable dynamic squat (S1RM = 128.0 ¡À 31.4 kg) and

an unstable dynamic squat (U1RM = 83.8 ¡À 17.3 kg) in a randomized order with a

30-min rest period between conditions. The second session consisted of the

performance of three trials each for 12 different conditions (unstable and

stable squats using three different absolute loads [six conditions] and unstable

and stable squats using three different relative loads [six conditions]).

>

> Results: Results revealed a statistically significant difference between S1RM

and U1RM values (P ¡Ü .05). The stable trials resulted in the same or a

significantly higher value for VL, BF and L1 muscle activity in comparison with

the unstable trials for all twelve conditions.

>

> Conclusions: Unstable squatting is of equal or less (depending on the loading

condition) benefit to improving or maximizing muscle activity during resistance

exercise.

>

> ==============

> Carruthers

> Wakefield, UK

>

[Guest guest]

This is done way too often is research. There will be imperfect correlation

between variables, but the researcher makes predictions in a macro environment

based on imperfect correlation in a micro environment. One of the reasons why

80% of the research is not very useful.

Hobman

Saskatoon, Canada

On 2010-08-17, at 1:14 PM, Casler wrote:

>

>

> -----Original Message----- by the Phantom

>

> ok... so the unstable squat didn't provide any more muscle stimulation

> despite the claims if I read this correctly?

>

> so why is this fad continuing to be used and sold as stimulating more muscle

> rather than normal squats using more weight and other safe modalities?

> pretty expensive to find 1 and train on it around here I've heard...

>

> Just wondering.

>

> Casler writes:

>

> Likely because most trainers don't understand how instability leads to

> " inhibition " rather than facilitation of primary movers.

>

> I presume the concept either started or was fueled by EMG readings on

> " stabilizers " not primary movers. Some Torso research found unstable

> actions caused increased " stabilizer " activity, and somehow the " unwashed "

> ran with it.

>

> Interestingly enough, the instability likely reduces the load and force

> capacity so much that the " overall " effect to conditioning the stabilizers

> is also reduced overall.

>

> So go figure.

>

> Incorrect interpretation of information is often the culprit in these cases.

>

> Drives me crazy (or at least provides assistance)

>

> Regards,

>

> Casler

> TRI-VECTOR 3-D Training Systems

> Century City, CA

> -II-----II-

>

>

[Guest guest]

That's a great point ! Who was it that posted the cartoon of how studies

flow into the mainstream?

Casey Gallagher CSCS

Snohomish, WA USA

Muscle Activity During Stable and Unstable Squatting

-----Original Message----- by the Phantom

ok... so the unstable squat didn't provide any more muscle stimulation

despite the claims if I read this correctly?

so why is this fad continuing to be used and sold as stimulating more muscle

rather than normal squats using more weight and other safe modalities?

pretty expensive to find 1 and train on it around here I've heard...

Just wondering.

Casler writes:

Likely because most trainers don't understand how instability leads to

" inhibition " rather than facilitation of primary movers.

I presume the concept either started or was fueled by EMG readings on

" stabilizers " not primary movers. Some Torso research found unstable

actions caused increased " stabilizer " activity, and somehow the " unwashed "

ran with it.

Interestingly enough, the instability likely reduces the load and force

capacity so much that the " overall " effect to conditioning the stabilizers

is also reduced overall.

So go figure.

Incorrect interpretation of information is often the culprit in these cases.

Drives me crazy (or at least provides assistance)

Regards,

Casler

TRI-VECTOR 3-D Training Systems

Century City, CA

-II-----II-

[Guest guest]

I completely agree. Add to this the fact that most studies that I am seeing

appearing in the mainstream strength and conditioning journals have just

laughable sample sizes and its a recipe for disaster.

Just randomly picking a copy of the journal of strength and conditioning

research off my desk and we can see the following in terms of sample sizes in

experimental research:

13, 8, 21, 35, 11, 8, 20 and 21 - that's just half an edition and I recon that's

some of the higher sizes! There are plenty of reliable and free programs that

can be found online which will calculate statistical power and required sample

size. Most of these studies would probably need a minimum of a few hundred

subjects to be even close to viable.

Andy Mclean

Edinburgh, Scotland, UK.

>

> >

> >

> > -----Original Message----- by the Phantom

> >

> > ok... so the unstable squat didn't provide any more muscle stimulation

> > despite the claims if I read this correctly?

> >

> > so why is this fad continuing to be used and sold as stimulating more muscle

> > rather than normal squats using more weight and other safe modalities?

> > pretty expensive to find 1 and train on it around here I've heard...

> >

> > Just wondering.

> >

> > Casler writes:

> >

> > Likely because most trainers don't understand how instability leads to

> > " inhibition " rather than facilitation of primary movers.

> >

> > I presume the concept either started or was fueled by EMG readings on

> > " stabilizers " not primary movers. Some Torso research found unstable

> > actions caused increased " stabilizer " activity, and somehow the " unwashed "

> > ran with it.

> >

> > Interestingly enough, the instability likely reduces the load and force

> > capacity so much that the " overall " effect to conditioning the stabilizers

> > is also reduced overall.

> >

> > So go figure.

> >

> > Incorrect interpretation of information is often the culprit in these cases.

> >

> > Drives me crazy (or at least provides assistance)

> >

> > Regards,

> >

> > Casler

> > TRI-VECTOR 3-D Training Systems

> > Century City, CA

> > -II-----II-

> >

> >

>

>

>

>

[Guest guest]

Geovanni

I am aware of the statistical procedures you outline. However no matter how much

care you take to account for low sample size it does not carry the same weight

as actually having a large sample size in the first place. Generally speaking

sample sizes in sports science papers are very low. Perhaps a couple hundred may

be overkill (although it depends what you are measuring and how accurately it

can be measured) but I regularity see 8 and 10 (or even fewer) subjects in

cross-over experiments with no indication of how sample size has been accounted

for.

Will Hopkins wrote the following regarding sample sizes:

" For an accurate estimate of the relationship between variables, a descriptive

study usually needs a sample of hundreds or even thousands of subjects; an

experiment, especially a crossover, may need only tens of subjects. "

It seems to me that low sample size should be occasionally excused when the

proper precautions have been made but not the norm as seems to be the case in

S & C research.

That is not to say that studies with low sample size are worthless but perhaps

we should be analysing them and applying them differently?

Just my view on the matter.

Andy Mclean

Edinburgh, Scotland, UK.

> > >

> > > >

> > > >

> > > > -----Original Message----- by the Phantom

> > > >

> > > > ok... so the unstable squat didn't provide any more muscle stimulation

> > > > despite the claims if I read this correctly?

> > > >

> > > > so why is this fad continuing to be used and sold as stimulating more

> > muscle

> > > > rather than normal squats using more weight and other safe modalities?

> > > > pretty expensive to find 1 and train on it around here I've heard...

> > > >

> > > > Just wondering.

> > > >

> > > > Casler writes:

> > > >

> > > > Likely because most trainers don't understand how instability leads to

> > > > " inhibition " rather than facilitation of primary movers.

> > > >

> > > > I presume the concept either started or was fueled by EMG readings on

> > > > " stabilizers " not primary movers. Some Torso research found unstable

> > > > actions caused increased " stabilizer " activity, and somehow the

> > " unwashed "

> > > > ran with it.

> > > >

> > > > Interestingly enough, the instability likely reduces the load and force

> > > > capacity so much that the " overall " effect to conditioning the

> > stabilizers

> > > > is also reduced overall.

> > > >

> > > > So go figure.

> > > >

> > > > Incorrect interpretation of information is often the culprit in these

> > cases.

> > > >

> > > > Drives me crazy (or at least provides assistance)

> > > >

> > > > Regards,

> > > >

> > > > Casler

> > > > TRI-VECTOR 3-D Training Systems

> > > > Century City, CA

> > > > -II-----II-

> > > >

> > > >

> > >

> > >

> > >

> > >

[Guest guest]

It depends on your goals Ed, but when you say your best results, how are you

measuring that? What do the Bosu squats add that you have noticed? Or the leg

press? Are you sure most of the benefits aren't from squatting?

Brock Leggins

Norwalk, IA

Sent from my U.S. Cellular BlackBerry® smartphone

Re: Re: Muscle Activity During Stable and Unstable

Squatting

Would you consider leg press to be a more stabalized movement than free weight

squats?  Can you handle more weight with leg press than squats?  Does that

make the leg press superior to squats?  What does this tell us?  What is the

weak link in our performance?  Does that imply that some instability in weight

training is good, but more is not?  How do we best train the weak link if it is

stabalizers and not prime movers?

 

I have found that I get best results (strength, balance, stabalizers and prime

movers) from arranging my workout like this:

 

1.  warmup

2.  sets 1 and 2 - squats on bosu 1/2 ball (unstable)

3.  sets 2 and 4 - free weight squats (partially stable)

4.  sets 5 and 6 leg press (most stable)

 

Ed White

Cape Cod, MA USA

 

==================================

[Guest guest]

Giovanni

p-values can be adjusted to take into account low sample sizes amongst other

things. That is very true and something that most 1st year sports science

students would learn. In most of the sports science research I have seen the

p-value is set at 0.05 or even 0.1 (usually if it's a pilot study). A few

studies lower the p-value (to 0.01) to account for amongst other factors small

sample sizes (but not always). This may go some way to reducing the probability

of reporting a false-positive but it is by no means ideal. Ideal would be to

have a larger sample size.

However I fail to see how you can say that the sample sizes I reported are in

line with the guidelines stated by Will Hopkins. I took a quasi-random selection

and 50% of them had fewer than 20 subjects and 25% less than 10. As I stated

this is fairly indicative of much of the research.

We may have to agree to differ on this topic but if sports science wants to be

taken more seriously out with our own niche I would suggest that larger sample

sizes in experimental research would be a good starting point. This was my

original point. By all means take into account small sizes but surely you must

agree that a more robust approach would be to actually have bigger samples.

I for one don't tend to pay too much attention to the majority of studies

utilising 7 or 8 participants unless they are an elite sample, the study is set

up to look specifically at individual responses or the study is looking at a new

area of research.

Andy Mclean

Edinburgh, Scotland, UK.

> > > > >

> > > > > >

> > > > > >

> > > > > > -----Original Message----- by the Phantom

> > > > > >

> > > > > > ok... so the unstable squat didn't provide any more muscle

> > stimulation

> > > > > > despite the claims if I read this correctly?

> > > > > >

> > > > > > so why is this fad continuing to be used and sold as stimulating

> > more

> > > > muscle

> > > > > > rather than normal squats using more weight and other safe

> > modalities?

> > > > > > pretty expensive to find 1 and train on it around here I've

> > heard...

> > > > > >

> > > > > > Just wondering.

> > > > > >

> > > > > > Casler writes:

> > > > > >

> > > > > > Likely because most trainers don't understand how instability leads

> > to

> > > > > > " inhibition " rather than facilitation of primary movers.

> > > > > >

> > > > > > I presume the concept either started or was fueled by EMG readings

> > on

> > > > > > " stabilizers " not primary movers. Some Torso research found

> > unstable

> > > > > > actions caused increased " stabilizer " activity, and somehow the

> > > > " unwashed "

> > > > > > ran with it.

> > > > > >

> > > > > > Interestingly enough, the instability likely reduces the load and

> > force

> > > > > > capacity so much that the " overall " effect to conditioning the

> > > > stabilizers

> > > > > > is also reduced overall.

> > > > > >

> > > > > > So go figure.

> > > > > >

> > > > > > Incorrect interpretation of information is often the culprit in

> > these

> > > > cases.

> > > > > >

> > > > > > Drives me crazy (or at least provides assistance)

> > > > > >

> > > > > > Regards,

> > > > > >

> > > > > > Casler

> > > > > > TRI-VECTOR 3-D Training Systems

> > > > > > Century City, CA

> > > > > > -II-----II-

> > > > > >

> > > > > >

> > > > >

> > > > >

> > > > >

> > > > >