Doug
A great posting - Thanks for forwarding the references and abstracts (I had
said I was going to do this this week- you have saved me loads of trouble).
I think, on its own, it may well be that TrAb plays a minor part in
stabilisation - I know it has to work in concert with the diagphragm and
pelvic floor muscles to be effective but I would like to hear more about the
research showing "that transversus abdominus is only a very minor
contributor to spinal stability during a selection of spinal stability
exercises". Do you know more about this - how do you research an individual
muscles degree of contribution to stability?
I think the present model of "Stabilisers" and "Mobilisers" may eventually
be dismantled as I suspect muscles are just all somewhere in the spectrum
but it has proved a useful model during the development and teaching of this
principle. I think the teaching model is that some muscles are positioned to
act (from an anatomical point of view) as stabilisers (because they have
little leverage to move the joint), and physiologically because they
contract with tonic-type contractions, less suited to ballistic movement.
However, the contention that stability is due to the concertend effort of
all muscles doesn't contradict this model - the researchers/teachers I have
heard lecturing have always insisted that the global mobilisers/local
stabilisers are part of a continuum of muscles that work together to move
and stabilise.
The last point about fear inhibiting TrAb activity I heard about recently
when Paul Hodges presented at the OCPPP meeting here in the UK. They
experimented on pigs with a fine-wire EMG and electric shocks (you can tell
when a pig is in fear because it's tail stops being curly - or is that the
other way round?) and fear = increased delay in TrAb contraction. This is
very interesting in the context of biopsychosocial models of disability
where disability is intimately related to fear-avoidance behaviour and
health beliefs.
John Spencer
----- Original Message -----
From: "Doug Bourne" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, August 21, 2002 6:07 AM
Subject: Re: Movements not Muscles?
> Time to get this discussion back on track. For those who haven't seen
> the Hides et al. RCT here is the reference with abstract:
>
> Spine 2001 Jun 1;26(11):E243-8
> Long-term effects of specific stabilizing exercises for first-episode
> low back pain.
>
> Hides JA, Jull GA, Richardson CA.
>
> Department of Physiotherapy, Mater Misericordiae Public Hospitals,
> South Brisbane, Queensland, Australia. [log in to unmask]
>
> STUDY DESIGN: A randomized clinical trial with 1-year and 3-year
> telephone questionnaire follow-ups. OBJECTIVE: To report a specific
> exercise intervention's long-term effects on recurrence rates in acute,
> first-episode low back pain patients. SUMMARY OF BACKGROUND DATA: The
> pain and disability associated with an initial episode of acute low back
> pain (LBP) is known to resolve spontaneously in the short-term in the
> majority of cases. However, the recurrence rate is high, and recurrent
> disabling episodes remain one of the most costly problems in LBP. A
> deficit in the multifidus muscle has been identified in acute LBP
> patients, and does not resolve spontaneously on resolution of painful
> symptoms and resumption of normal activity. Any relation between this
> deficit and recurrence rate was investigated in the long-term. METHODS:
> Thirty-nine patients with acute, first-episode LBP were medically
> managed and randomly allocated to either a control group or specific
> exercise group. Medical management included advice and use of
> medications. Intervention consisted of exercises aimed at rehabilitating
> the multifidus in cocontraction with the transversus abdominis muscle.
> One year and three years after treatment, telephone questionnaires were
> conducted with patients. RESULTS: Questionnaire results revealed that
> patients from the specific exercise group experienced fewer recurrences
> of LBP than patients from the control group. One year after treatment,
> specific exercise group recurrence was 30%, and control group recurrence
> was 84% (P < 0.001). Two to three years after treatment, specific
> exercise group recurrence was 35%, and control group recurrence was 75%
> (P < 0.01). CONCLUSION: Long-term results suggest that specific exercise
> therapy in addition to medical management and resumption of normal
> activity may be more effective in reducing low back pain recurrences
> than medical management and normal activity alone.
>
> I'm sure that many exercises have been shown to be beneficial but what
> strikes me is the drastic decrease in recurrence rate. This is pretty
> amazing especially considering some of the valid comments others have
> made. Mel stated he " also knew that activation in a given limited
> situation does not necessarily mean integrated optimal involvement in
> some complex motor activity involving multiarticular movement whose
> patterns of muscular and other soft tissue involvement change from
> moment to moment." It also doesn't mean that a muscle pattern learned
> in a limited situation will transfer to a more complex or different
> motor activity. This was drilled into us in Neuro at school. This
> study suggests that with this exercise program there may be transfer to
> real life situations (by means of decreased recurrence).
>
> Now to switch sides. In an earlier post I mentioned the special session
> on spinal stability at this years WCB. I also mentioned the names of
> the people who made up the panel (Hodges, McGill, Panjabi, Stokes,
> Solomonow). Although I'm sure that these people all believe that spinal
> stability is important, they disagree on many points (which you would
> expect in a developing field of biomechanics). Although many physios
> are familiar with Hodges work and Panjabi's neutral zone hypothesis I
> doubt many have read much of McGill, Stokes or Solomonow's work. I
> didn't recognize Solomonow's name before the conference. This work is
> important (along with Cholewicki, Granata, Marras, and others) for
> understanding the biomechanics behind spinal stability.
>
> It is becoming in apparent in the research that classifying muscles as
> either local stabilizers or global movers is flawed. Stability relies
> on the concerted effort of all muscles (even segmental stability).
> Cholewicki J, VanVliet JJ 4th.
> Relative contribution of trunk muscles to the stability of the
> lumbar spine during isometric exertions.
> Clin Biomech (Bristol, Avon). 2002 Feb;17(2):99-105.
>
> A couple of McGill's grad students presented interesting research that
> transversus abdominus is only a very minor contributor to spinal
> stability during a selection of spinal stability exercises.
>
> Hodges presented research showing that the abnormalities in transversus
> function could be replicated by making normal subjects afraid of moving
> (by electric shocks) does this suggest that transversus fuction will be
> restored when patient's are not afraid to move anymore?
>
> Any comments?
>
|