Guest guest Posted January 22, 2003 Report Share Posted January 22, 2003 Scherger wrote on his web site: <In our first manual, we demonstrated that there was functionally no such thing as a 2nd class lever. We have since learned that there are teachers who still want to use classic instruction because they think that this methodology is still valid for teaching force of effort. We will now demonstrate that this is erroneous teaching.> **** It's been awhile since I had biomechanics...but isn't the ankle/foot a 2nd class lever (ie. plantarflexion movement)? Tim Stark, DC, DACBSP, CSCS, LN West Fargo, ND, USA Quote Link to comment Share on other sites More sharing options...
Guest guest Posted January 30, 2003 Report Share Posted January 30, 2003 , I haven't read the 2000 article, but want to know (if you have time), how its conclusions differ from the Hodges 1999 review (Is there a role for TA in lumbo-pelvic stability)? I understood that the superficial muscles (IO EO RA ES) acted in a preparatory manner with respect to limb movement(ie controlling trunk orientation) and trunk movement but TA acted independently of movement, centre of mass etc... (If this question has been previously addressed I will of course be happily redirected) Much obliged Sam Bowden Townsville ----------- >It is not all beer and skittles with the leading No.1 " core stability " >concept for the UK or anywhere else. > >It seems as though core stability and trunk stabilizers don’t always behave >as predicted or hoped: > >If you read Hodges et al 2000, as quoted in this thread, they actually >find something different from what they went looking for. The famed >surreptitious apparent stabilizer (TA) of the trunk did not respond in >any particular pattern as predicted. There was no describable >involvement of this muscle in trunk involvement during arm movements. > >In fact what they did find to report was that trunk MOTION preceded arm >motion in particular patterns. Yes MOTION, not stabilization. Perhaps it >could be that trunk motion is a component of human function? Does trunk >MOTION contribute to walking (Inman et al 1981), reaching (Cavanagh et >al 1999), throwing (Pappas et al 1985), stair climbing (Krebs et al >1992) etc or does it merely stabilize and stiffen as practised in >trunk/lumbar stabilization exercises? > >Pelvic rotation in the sagittal plane during trunk flexion is diminished >in subjects with chronic low back pain (Mayer et al 1984, Dolan & >1993..etc..). What is the rationale for trunk stabilization exercises >for CLBP when in fact these people are stiff or do not utilize pelvic >motion as a part of trunk bending? Why ask them to stiffen the pelvis in > " the neutral position " or as traditionally taught in full posterior >pelvic tilt (agghhhh)? > >Could this not be a hangover from 1950s America when " tits out and arse >in " was the norm in the military or for the public basic posture when >any public display of pelvic movement a la Elvis was banned?? Is modern >PT " stabilization " simply a relic of 1950's cultural attitude? Or a >definitive researchable science? I stray but……really. > >[Your remarks here are most relevant to the vastly distorted trendy subject >of " core stability " and " stability training " - in previous letters and >articles >I have stressed that various motion strategies like this are an important >part of the stabilisation process, including the stepping reflex, in which >the >person moves to shift the base of support of the body instead of rigidly >trying >to keep the whole body, the trunk or other parts " glued " to the same place >when exposed to any perturbation. Mel Siff] > > Burgess >Boston USA > >--------------- > >Cavanaugh, J. T., M. Shinberg, L. Ray, K. M. Shipp, M. Kuchibhatla and >M. Schenkman (1999). “Kinematic characterization of standing reach: >comparison of younger vs. older subjects.” Clin Biomech (Bristol, Avon) >14(4): 271-9. > >Dolan, P. and M. A. (1993). “Influence of lumbar and hip mobility >on the bending stresses on the lumbar spine.” Clin Biomech 8: 185-92. > >Hodges, P. W., A. G. Cresswell, K. Daggfeldt and A. Thorstensson (2000). >“Three dimensional preparatory trunk motion precedes asymmetrical upper >limb movement.” Gait & Posture 11(2): 92-101. > >Inman, V. T., H. J. Ralston and F. Todd (1981). Human walking. >Baltimore, and Wilkins. > >Krebs, D. E., D. Wong, D. Jevsevar, P. O. Riley and W. A. Hodge (1992). >“Trunk kinematics during locomotor activities.” Phys Ther 72(7): 505-14. > >Mayer, T., A. Tencer, S. Kristiferson and V. Mooney (1984). “Use of >noninvasive techniques for quantification of spinal range-of-motion in >normal subjects and chronic low back dysfunction patients.” Spine 9(6): >588-95. > >Pappas, A. M., R. M. Zawacki and T. J. Sullivan (1985). “Biomechanics of >baseball pitching: a preliminary report.” The American Journal of Sports >Medicine 13(4): 216-22. > >------------ * Don't forget to sign all letters with full genuine name and city of residence if you wish them to be published! Quote Link to comment Share on other sites More sharing options...
Guest guest Posted January 30, 2003 Report Share Posted January 30, 2003 Sam, Do read the article. It concluded that " TA behaved without any recognizable pattern during arm raising. " I believe that the TA, lumbar stabilization, PT model is a red herring for trunk control. It is not about individual muscles but action/synergies/organization of the skeleton etc........... the brain does not know individual muscles....TA is not that significant individually. Whatever the IO EO RA ES muscles did or do is only relevant as a description of how the trunk behaved. The brain controls bones and synergies, not individual muscles in isolation. Muscles are only the final motor output/pathway of planning and have little or no role in the planning and organization of complex movement. <<I understood that the superficial muscles (IO EO RA ES) acted in a preparatory manner with respect to limb movement(ie controlling trunk orientation) and ...> It is not a matter of a stiff trunk orienting for arm action. The trunk actually flexes, rotates and side bends in all planes with arm action.....it is not a stiff structure that merely orientates. Maybe it does not move much in this contrived experimental situation, but in life the relationship of arm to trunk is enormous. See Pappas et al 1985, for example- the speed of a baseball from a pitch has been decomposed into 50% shoulder action and 50% trunk and leg action. In fact, I would propose that the trunk can be modelled as the prime mover of arm action and that the arm/shoulder/trunk action is a whip-like action on the end of a trunk action. The trunk is not just a stiff base that orientates - it is a mobile powerful part of the action. Tired of the PT pseudoscience mythology.......... Burgess Boston USA * Don't forget to sign all letters with full genuine name and city of residence if you wish them to be published! Quote Link to comment Share on other sites More sharing options...
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