Hi

I would be interested in further explanation of the Starling's Law paradox.

Owen Sant' Angelo

Physiotherapy Student
University of Malta

----- Original Message -----
From: <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, March 29, 2000 10:51 PM
Subject: PILATES & PHYSIOLOGY?


> On 3/29/00, Simon Mesner<[log in to unmask]> wrote:
>
> <<  I never stated that muscles lengthen beyond their resting level, if
you
> had fully read my comments, but stated that eccentric muscle contraction
is
> one where the contractile elements of the muscle are consuming energy
whilst
> the muscle lengthens.>>
>
> ***All muscle action is measured with reference to the resting state,
unless
> clearly stated otherwise in a specific research study.  No matter how many
> times I read your original letter, I cannot find nothing about energy
> consumption.  Anyway, ALL muscle action, be it isometric, concentric or
> eccentric, consume energy. How does this comment have any bearing on your
> explanation of why Pilates methods allegedly produce longer muscles?
>
> Here is your letter - where do you mention anything about energy processes
> involved muscle action?
>
> <<I am suprised that you are slagging off the muscle physiology behind
Pilates
>
> when you are unable to adequately describe muscle contraction.  Muscles
>
> activate both when shortening and lengthening, the latter being eccentric
>
> muscle contraction.  I also believe that when the Pilates people refer to
>
> longer muscles they are describing muscles that are worked through out
range
>
> rather than only at inner range, something which weight training
programmes
>
> do not identify with regard to abdominal training at least.>>
>
> <<My example of sit ups (abdominal exercises done poorly in weight
training
> regimes) was to point out that although the performer concentrically
> exercises their muscles they do not necessarily eccentrically work them as
> they can rely on gravity, a passive force to return to the resting
level.>>
>
> ***In other words, you are suggesting that people do not necessarily use
any
> eccentric action during supine sit-ups.  This means that, once the
concentric
> phase sitting-up phase is over, the performer simply drops back under the
> influence of gravity without any eccentric abdominal action to control any
> stage of the descent.  Nobody ever does that during a sit-up, unless they
> wish to damage the back during all those uncontrolled impacts with the
floor!
>
> Some level of  (rate-dependent or fatigue-dependent) eccentric activity is
a
> characteristic of non-pathological control in all muscle action, be it
> against inertial loads such as weights (or bodymass) or non-inertial loads
> such as elastic bands.  Were this not true, you would have to rely
entirely
> on impact with a rigid surface or the ligaments to terminate any joint
> action, which is hardly the safest or most efficient way of controlling
joint
> movement.
>
> I have taken many abdominal EMGs and have yet to encounter a single person
> who executes sit-ups without some eccentric action. While the rate of
descent
> and ascent may be controlled, and some people choose to descend more
rapidly
> than others, this does not imply that no eccentric abdominal action
occurs.
> On the contrary, those who drop back quickly produce very marked EMG
activity
> during the latter stages of the eccentric movement.   Those who lower
> themselves at a more leisurely rate by deliberately slowing down the
> eccentric action do not produce this type of peak EMG activity.
>
> Now that this physiological hurdle has been surmounted, kindly explain how
> this point relates to some form of special Pilates sit-ups or abdominal
> exercise that distinguishes it above all other forms of resistance
exercise,
> especially regarding how Pilates manages to produce longer muscles than
> weight training methods.
>
>
> <<The other point you raise is believe one of terminology.  I concede that
I
> may not have explained it in your terms but does that mean that you are
> necessarily correct?  Muscles contract more effectively at a position
where
> the overlap of filaments is optimal.  As such, using the English language
> correctly one could describe a range of muscle length.  As any physiology
> textbook will explain, muscles contract more effectively in a 'mid-range'
> rather than at 'long' or 'short' range.  I refer you to the length-tension
> relationship of a muscle. >>
>
> ***What exactly do you mean by 'optimal'?  It is  not necessarily
synonymous
> with maximum overlap between the actin-myosin components (not the
> 'filaments'), nor does it necessarily refer to some midway position of
> overlap.  If you examine the standard muscle tension-length relationship
to
> which you seem to be referring, you may notice that the graphs obtained
(in
> vitro) in those studies referred to cases which are non-ballistic or
> non-explosively initiated.
>
> You will also recall that Starling's Law which states that a muscle will
> produce its greatest force from its most lengthened (prestretched) state.
> Since we know that muscle action seems to be weakest when the degree of
> actomyosin overlap is least, this would seem to pose a serious paradox -
> namely, how can a muscle produce its greatest force when it is taken to
its
> maximum prestretched length, i.e., to its apparently weakest physiological
> state?  Maybe you would like to try to explain this apparent paradox,
since
> you have invoked studies of muscle tension-length to explain your support
for
> Pilates specific muscle structure and function.
>
>
> <<You seem to have a pathological aversion to Pilates.  I, as you so
> correctly guessed, have no formal knowledge of Pilates nor do I think it
is
> the best thing since sliced bread.  I do not have a problem with weight
> training either.  >>
>
> ***No, I actually have no aversion to Pilates at all, just the manner in
> which some latter-day marketeers are trying to explain or sell it.   As
> someone who underwent a spell of Pilates training from a delightful group
in
> LA, I have a great respect for some of the work that Joseph Pilates
> formalised so many years ago, just as Knott & Voss did the same with PNF,
and
> McKenzie did with yogic based back routines several decades ago.  In fact,
I
> see that Pilates and PNF, to mention but two disciplines, could well be
used
> to complement each other. What I do have is a pathological aversion to any
> method of training or rehabilitation being marketed or explained on the
basis
> of sheer mythology, non-science and emotive attachment.
>
> <<What I dislike are either being done badly, unenlightened health care
> professionals and those who condescend trans atlantically>>
>
> ***Ditto - especially when unenlightenment is passed off as enlightenment!
> What a pity that I moved to the USA from Africa before we discussed this
> issue!   A few years ago I could have condescended across different
> continents and seas!  I might even have done it locally in the UK, because
I
> regularly spend time staying in some lovely wooded areas of Surrey or with
> Scottish relatives in the Highlands, which offer an even better location
from
> which to condescend over the rest of Britain!
>
> Enough 'o that, laddie, I'm awa the noo!
>
> Dr Mel C Siff
> Denver, USA
> [log in to unmask]
>
>



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