View Full Version : Re: Subluxation Paradox: PP126

Beverly J. Burke
02-13-2002, 02:31 AM
My ruminations on Mel's ruminations.
> =20
> I think one problem is an assumption of of the behavior of so
> called,resting muscle. Different experimenters have looked at different
> levels of muscle Maximum Voluntary Contraction, MVC and fatigue as a cause
> of muscle pain and musculoskeletal injury. It seems that fatigue does occur
> at some very low contractile levels when the contractions are sustained.
> Westgaard looked at time periods of 1-2 hours. If fatigue is caused by low
> level MVC, then perhaps the collapse of functional muscle units creates
> opportunities for different forces to be communicated over a joint. These
> forces may not be generated from a voluntary command but from a
> collapse of a muscle unit due to fatigue.
> It is possible that SUSTAINED low-level contraction commands coming from a
> CNS commnand produce contraction at the connective tissue level. Since
> connective tissue covers muscle fibers as well as muscle bellies the over
> all mechanical effect of connective tissue may be like a webbed net that
> causes contraction to spread over functional units or the entire muscle
> causing functional unit contractions that may produce enough force to
> fatigue some units.
> See
> Westgaard, R.H. Measurement and evaluation of postural load in occupationa=
> l
> work situations. 1988. European J. of Applied Physiology.
> Edwards, R. Hypotheses of peripheral and central mechanimsm underlying
> occupational muscle pain and injury. 1988. European J. of Applied
> Physiology.
> Gandevia, S.C. Neural control in human muscle fatigue: changes in muscle
> afferents, moto neurons and moto cortical drive 1988 Acta Physiologia
> Scandinavia=20
> Gandevia, S.C. 1996. Supraspinal factors in human muscle fatigue: evidence
> for suboptimal output from the motor cortex Journal of Physiology.
> --=20
> Beverly Burke RN CMA CIE
> 19110 Suncrest Dr.
> West Linn, Oregon 97068
> 503-636-4203=20

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