muskel fiber

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Er det noen har som har hørt om flere typer muskelfibre enn type I og type IIA og IIB ?

mener å ha lest en gang om både type I AogB og type II A,B,C og D

[EmPhAziA]

Heizann!

Etter tre år med Treningslære, mner jeg å kunne si at du har rett angående muskelfibertyper; i menneskekroppen finner vi type 1-fibre og type 2a og type 2b. Dette sier også læreboka mi, men det er godt mulig at det har skjedd noe nytt på forskningsfronte, men dette har jeg ikke hørt.

[daccordi]

Heizann!

Etter tre år med Treningslære, mner jeg å kunne si at du har rett angående muskelfibertyper; i menneskekroppen finner vi type 1-fibre og type 2a og type 2b. Dette sier også læreboka mi, men det er godt mulig at det har skjedd noe nytt på forskningsfronte, men dette har jeg ikke hørt.

joda jeg har funnet svaret selv !

det finnes en type II X/D

[daccordi]

Heizann!

Etter tre år med Treningslære, mner jeg å kunne si at du har rett angående muskelfibertyper; i menneskekroppen finner vi type 1-fibre og type 2a og type 2b. Dette sier også læreboka mi, men det er godt mulig at det har skjedd noe nytt på forskningsfronte, men dette har jeg ikke hørt.

J Appl Physiol 1996 Jan;80(1):261-70 (ISSN: 8750-7587) Delp MD; Duan C

Department of Health and Kinesiology, Texas A&M University, College Station 77843-4243, USA.

A population of muscle fibers containing a myosin heavy-chain isoform IId (or 2x) has recently been identified in rat muscle. The purpose of this study was to histochemically determine the relative population and size of muscle fibers composed of type IID/X fibers as well as type I, IIA, and IIB fibers to estimate the absolute mass of the different types of fibers in rat muscle. In addition, muscle citrate synthase activity was measured to determine the relationship between fiber composition and muscle oxidative capacity. Seventy-six muscles or muscle parts from the face, neck, shoulder, arm, trunk, hip, thigh, and leg of three adult (4.5-5 mo of age) male Sprague-Dawley rats were removed, weighed, and frozen for histochemical and biochemical analyses. The data demonstrated that type IIB fibers make up 71% of the total muscle mass, type IID/X fibers 18%, type IIA fibers 5%, and type I fibers 6%. The mean cross-sectional area across all muscles was 5,078 +/- 175 microns 2 for type IIB fibers, 3,078 +/- 105 microns2 for type IID/X fibers, 2,045 +/- 80 microns2 for type IIA fibers, and 1,898 +/- 90 microns2 for type I fibers. Citrate synthase activity, an indicator of muscle mitochondrial content, was most closely related to the population of type IIA fibers and was in the rank order of type IIA > I > IID/X > IIB. NADH-tetrazolium reductase staining intensity also confirmed this order. These data demonstrate that type IID/X fibers make up a significant portion of the adult rat muscle mass and are intermediate to type IIA and IIB fibers in regard to fiber size and oxidative potential.