Muscle fiber types and size in trained and untrained muscles of elite athletes

1985 ◽  
Vol 59 (6) ◽  
pp. 1716-1720 ◽  
Author(s):  
P. A. Tesch ◽  
J. Karlsson
Keyword(s):  
Muscle Fiber ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Deltoid Muscle ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Relative Distribution ◽  
Long Distance ◽  
Tissue Samples ◽  
Greco Roman

Tissue samples were obtained from vastus lateralis and deltoid muscles of physical education students (n = 12), Greco-Roman wrestlers (n = 8), flat-water kayakers (n = 9), middle- and long-distance runners (n = 9), and olympic weight and power lifters (n = 7). Histochemical stainings for myofibrillar adenosinetriphosphatase and NADH-tetrazolium reductase were applied to assess the relative distribution of fast-twitch and slow-twitch (ST) muscle fiber types and fiber size. The %ST was not different in the vastus (mean SD 48 +/- 14) and deltoid (56 +/- 13) muscles. The %ST was higher (P less than 0.001), however, in the deltoid compared with vastus muscle of kayakers. This pattern was reversed in runners (P less than 0.001). The %ST of the vastus was higher (P less than 0.001) in runners than in any of the other groups. The %ST of the deltoid muscle was higher in kayakers than in students, runners (P less than 0.001), and lifters (P less than 0.05). The mean fiber area and the area of ST fibers were greater (P less than 0.01) in the vastus than the deltoid muscle. Our data show a difference in fiber type distribution between the trained and nontrained muscles of endurance athletes. This pattern may reflect the adaptive response to long-term endurance training.

Carnitine metabolism in human muscle fiber types during submaximal dynamic exercise

1996 ◽  
Vol 80 (3) ◽  
pp. 1061-1064 ◽  
Author(s):  
D. Constantin-Teodosiu ◽  
S. Howell ◽  
P. L. Greenhaff
Keyword(s):  
Muscle Fiber ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Group Formation ◽  
Free Carnitine ◽  
Muscle Fiber Types ◽  
Type I ◽  
Fiber Types ◽  
Carnitine Metabolism ◽  
Type I Fibers

The effect of prolonged exhaustive exercise on free carnitine and acetylcarnitine concentrations in mixed-fiber skeletal muscle and in type I and II muscle fibers was investigated in humans. Needle biopsy samples were obtained from the vastus lateralis of six subjects immediately after exhaustive one-legged cycling at approximately 75% of maximal O2 uptake from both the exercised and nonexercised (control) legs. In the resting (control) leg, there was no difference in the free carnitine concentration between type I and II fibers (20.36 +/- 1.25 and 20.51 +/- 1.16 mmol/kg dry muscle, respectively) despite the greater potential for fat oxidation in type I fibers. However, the acetylcarnitine concentration was slightly greater in type I fibers (P < 0.01). During exercise, acetylcarnitine accumulation occurred in both muscle fiber types, but accumulation was greatest in type I fibers (P < 0.005). Correspondingly, the concentration of free carnitine was significantly lower in type I fibers at the end of exercise (P < 0.001). The sum of free carnitine and acetylcarnitine concentrations in type I and II fibers at rest was similar and was unchanged by exercise. In conclusion, the findings of the present study support the suggestion that carnitine buffers excess acetyl group formation during exercise and that this occurs in both type I and II fibers. However, the greater accumulation of acetylcarnitine in type I fibers during prolonged exercise probably reflects the greater mitochondrial content of this fiber type.

Muscle capillary supply and fiber type characteristics in weight and power lifters

1984 ◽  
Vol 56 (1) ◽  
pp. 35-38 ◽  
Author(s):  
P. A. Tesch ◽  
A. Thorsson ◽  
P. Kaiser
Keyword(s):  
Fiber Type ◽  
Vastus Lateralis ◽  
Periodic Acid ◽  
Capillary Density ◽  
Muscle Fiber Types ◽  
Vastus Lateralis Muscle ◽  
Fiber Types ◽  
Relative Distribution ◽  
Periodic Acid Schiff ◽  
Capillary Supply

Muscle tissue samples were obtained from vastus lateralis muscle of elite weight/power lifters (WL/PL, n = 8), endurance athletes (EA, n = 8), and nonathletes (NA, n = 8). Histochemical stainings for myofibrillar ATPase, NADH-tetrazolium reductase, and amylase-periodic acid-Schiff, respectively, were undertaken to assess relative distribution of fast-twitch (FT) and slow-twitch (ST) muscle fiber types, fiber size, and capillary supply [capillaries per fiber (cap X fib-1) and capillaries per mm2 (cap X mm-2)]. Fiber type distribution in WL/PL, EA, and NA averaged 59 +/- 6 (SD), 40 +/- 11, and 61 +/- 10% FT. Values for mean fiber area and FT/ST area were significantly greater in WL/PL compared with values obtained in EA and NA. Similar values for cap X fib-1 were observed WL/PL (2.06 +/- 0.74) and NA (2.16 +/- 0.34). EA exhibited greater cap X fib-1 (3.11 +/- 0.73) than WL/PL (NS) and NA (P less than 0.01). However, cap X mm-2 in WL/PL (199 +/- 29) was lower than in EA (401 +/- 61, P less than 0.001) and NA (306 +/- 29, P less than 0.01). It is suggested that heavy resistance training in contrast to endurance training does not result in increased capillary density. Instead, as a consequence of fiber hypertrophy induced by muscle overloading, capillary density is decreased.

Blood flow to different skeletal muscle fiber types during contraction

1983 ◽  
Vol 245 (2) ◽  
pp. H265-H275 ◽  
Author(s):  
B. G. Mackie ◽  
R. L. Terjung
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Muscle Fiber ◽  
Fiber Type ◽  
Oxidative Capacity ◽  
Skeletal Muscle Fiber ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Blood Flows ◽  
Fast Twitch

Blood flow to fast-twitch red (FTR), fast-twitch white (FTW), and slow-twitch red (STR) muscle fiber sections of the gastrocnemius-plantaris-soleus muscle group was determined using 15 +/- 3-microns microspheres during in situ stimulation in pentobarbital-anesthetized rats. Steady-state blood flows were assessed during the 10th min of contraction using twitch (0.1, 0.5, 1, 3, and 5 Hz) and tetanic (7.5, 15, 30, 60, and 120/min) stimulation conditions. In addition, an earlier blood flow determination was begun at 3 min (twitch series) or at 30 s (tetanic series) of stimulation. Blood flow was highest in the FTR (220-240 ml X min-1 X 100 g-1), intermediate in the STR (140), and lowest in the FTW (70-80) section during tetanic contraction conditions estimated to coincide with the peak aerobic function of each fiber type. These blood flows are fairly proportional to the differences in oxidative capacity among fiber types. Further, their absolute values are similar to those predicted from the relationship between blood flow and oxidative capacity found by others for dog and cat muscles. During low-frequency contraction conditions, initial blood flow to the FTR and STR sections were excessively high and not dependent on contraction frequency. However, blood flows subsequently decreased to values in keeping with the relative energy demands. In contrast, FTW muscle did not exhibit this time-dependent relative hyperemia. Thus, besides the obvious quantitative differences between skeletal muscle fiber types, there are qualitative differences in blood flow response during contractions. Our findings establish that, based on fiber type composition, a heterogeneity in blood flow distribution can occur within a whole muscle during contraction.

Human Skeletal Muscle Fiber Types: Delineation, Development, and Distribution

1997 ◽  
Vol 22 (4) ◽  
pp. 307-327 ◽  
Author(s):  
Robert S. Staron
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Human Skeletal Muscle ◽  
Fiber Type ◽  
Skeletal Muscle Fiber ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Key Words Aging ◽  
Fiber Number ◽  
Human Limb

This brief review attempts to summarize a number of studies on the delineation, development, and distribution of human skeletal muscle fiber types. A total of seven fiber types can be identified in human limb and trunk musculature based on the pH stability/ability of myofibrillar adenosine triphosphatase (mATPase). For most human muscles, mATPase-based fiber types correlate with the myosin heavy chain (MHC) content. Thus, each histochemically identified fiber has a specific MHC profile. Although this categorization is useful, it must be realized that muscle fibers are highly adaptable and that innumerable fiber type transients exist. Also, some muscles contain specific MHC isoforms and/or combinations that do not permit routine mATPase-based fiber typing. Although the major populations of fast and slow are, for the most part, established shortly after birth, subtle alterations take place throughout life. These changes appear to relate to alterations in activity and/or hormonal levels, and perhaps later in life, total fiber number. Because large variations in fiber type distribution can be found within a muscle and between individuals, interpretation of data gathered from human muscle is often difficult. Key words: aging, myosin heavy chains, myogenesis, myofibrillar adenosine triphosphate

Metabolic variation among alpha-motoneurons innervating different muscle-fiber types. I. Oxidative enzyme activity

1984 ◽  
Vol 51 (3) ◽  
pp. 529-537 ◽  
Author(s):  
D. W. Sickles ◽  
T. G. Oblak
Keyword(s):  
Optical Density ◽  
Muscle Fiber ◽  
Enzyme Activities ◽  
Tibialis Anterior ◽  
Fiber Type ◽  
Ventral Horn ◽  
Oxidative Enzyme ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Fast Twitch

We have examined the oxidative metabolism of rat alpha-motoneurons innervating muscles composed predominantly of one muscle-fiber type. Intramuscular injections of horseradish peroxidase (HRP) into the tensor fasciae latae (TFL) (approximately 94% fast-twitch glycolytic fibers, FG), tibialis anterior (TA) (approximately 66% fast-twitch oxidative-glycolytic, FOG; 32% FG), and soleus (SOL) (approximately 84% slow-twitch oxidative, SO) muscles permitted identification of motoneurons innervating these muscles. gamma-Motoneurons (less than 25-micron average soma diameter) were eliminated from the sampling. The alpha-motoneurons innervating the TFL were considered as FG, those innervating the tibialis anterior as FOG, and those of the soleus as SO. Alternate 5-micron serial cryostat sections were processed for HRP and nicotinamide adenine dinucleotide-diapharase (NADH-D) (oxidative enzyme) activities. Controls were included to assure reliability of reaction product quantitation. Motoneuron pools of each muscle were characterized by their shape and location within the ventral horn. Cells identified on HRP sections as innervating each of the muscles were located on sections processed for NADH-D activity. The optical density of motoneurons in sections processed for NADH-D activity was measured with a Zeiss Zonax MPM 03 microdensitometer. The mean relative NADH-D activities (optical density) of alpha-motoneurons innervating the TFL (FG), TA (FOG), and SOL(SO) muscles were 0.261, 0.305, and 0.447, respectively. Although some overlap in distribution of enzyme activities was observed, statistical analysis indicated significant differences between the NADH-D activities of each type of alpha-motoneuron. This is the first report of any metabolic difference in alpha-motoneurons belonging to different motor-unit types.(ABSTRACT TRUNCATED AT 250 WORDS)

Inducible isoform of HSP70 is constitutively expressed in a muscle fiber type specific pattern

1991 ◽  
Vol 261 (5) ◽  
pp. C774-C779 ◽  
Author(s):  
M. Locke ◽  
E. G. Noble ◽  
B. G. Atkinson
Keyword(s):  
Muscle Fiber ◽  
Fiber Type ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Constitutive Expression ◽  
Muscle Fiber Types ◽  
Type I ◽  
Fiber Types ◽  
Nylon Membrane ◽  
White Gastrocnemius

The most prominent group of stress or heat-shock proteins (HSPs) has an Mr of approximately 70,000 and is collectively referred to as the HSP70 family. The extent of stress inducibility and subcellular location of the various HSP70 isoforms differ, but all appear to be involved with ATP-dependent stabilization or solubilization of proteins. One isoform, termed the inducible isoform of HSP70 (HSP72i), is normally absent in unstressed cells. In a previous study, we detected a protein corresponding in Mr and pI to HSP72i in unstressed rat muscle. Therefore, it was of interest to determine if this expression in unstressed muscle cells is general or confined to specific muscle fiber types. To answer this question we have employed various rat hindlimb muscles that differ in fiber type proportion from predominantly type I (soleus) to predominantly type IIB (white gastrocnemius). Proteins from muscle homogenates were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, blotted to a nylon membrane, probed with a monoclonal antibody for HSP72i, and visualized using an alkaline phosphatase-conjugated secondary antibody. Immunoblot analyses demonstrate the constitutive expression of HSP72i in rat muscles comprised primarily of type I muscle fibers (soleus), but not in muscles comprised primarily of type IIB fibers (white gastrocnemius). In muscles of mixed fiber type, HSP72i content is roughly proportional to the percentage of type I fibers. These results substantiate that unstressed rat muscles express the inducible HSP72 isoform and demonstrate that its constitutive expression is proportional to the type I muscle fiber composition.

Mitochondrial reticulum in limb skeletal muscle

1986 ◽  
Vol 251 (3) ◽  
pp. C395-C402 ◽  
Author(s):  
S. P. Kirkwood ◽  
E. A. Munn ◽  
G. A. Brooks
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Vastus Lateralis ◽  
Skeletal Muscle Fiber ◽  
Muscle Fiber Types ◽  
Mitochondrial Morphology ◽  
Fiber Types ◽  
Fast Twitch ◽  
Mitochondrial Reticulum ◽  
Superficial Portion

High-voltage electron microscopy at 1,500 kV was used to examine mitochondrial morphology in three skeletal muscles of the rat. The soleus, deep portion of the vastus lateralis, and superficial portion of the vastus lateralis muscles were examined to represent slow-twitch oxidative, fast-twitch oxidative, glycolytic, and fast-twitch glycolytic skeletal muscle fiber types, respectively. Muscle samples were removed from six female Wistar rats. The tissues were fixed using standard electron microscopic techniques and were sectioned transversely with respect to muscle fiber orientation to approximately 0.5-micron thickness. The sections were stained on grids with uranyl acetate and Reynolds' lead citrate. Results revealed a mitochondrial reticulum in all three skeletal muscle fiber types. Stereological analyses of the electron micrographs were performed to measure volume densities and surface-to-volume ratios of mitochondria in the muscle samples. Cross-sectional volume densities of mitochondria in the soleus (15.5 +/- 1%) and deep portion of the vastus lateralis (16.1 +/- 2%) were significantly greater (P less than 0.05) than in the superficial portion of the vastus lateralis (8.7 +/- 1%). Surface-to-volume ratios of mitochondria were not significantly different between fiber types. It was concluded that the mitochondria in mammalian limb skeletal muscle are a reticulum, or network.

Muscle Fiber Types, Characteristics and Meat Quality

2013 ◽  
Vol 634-638 ◽  
pp. 1263-1267
Author(s):  
Lin Su ◽  
Hui Li ◽  
Xue Xin ◽  
Yan Duan ◽  
Xiao Qing Hua ◽  
...  
Keyword(s):  
Meat Quality ◽  
Muscle Fiber ◽  
Fiber Type ◽  
Influence Factors ◽  
Muscle Fiber Type ◽  
Basic Unit ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Type Conversion ◽  
Fiber Type Distribution

Muscle fiber is the basic unit of muscle tissue, this paper summarized the types of muscle fiber of animals, the influence factors of muscle fiber type distribution and the muscle fiber type conversion in the process of growth constantly. Discuss the important effect of muscle fiber type on meat quality.

scholarly journals Skeletal muscle and fiber type-specific intramyocellular lipid accumulation in obese mice

2021 ◽  
Author(s):  
Nejc Umek ◽  
Simon Horvat ◽  
Erika Cvetko
Keyword(s):  
Muscle Fiber ◽  
Lipid Accumulation ◽  
High Fat Diet ◽  
Fiber Type ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Intramyocellular Lipid ◽  
Obese Mice ◽  
Slow Twitch ◽  
Fast Twitch

In obesity, accumulation of lipid droplets in skeletal muscle fibers and a shift towards fast muscle fiber types can both contribute to insulin resistance. However, it is not yet clear how intramyocellular lipid accumulation and fiber type changes are associated. Therefore, we investigated to what extent the lipids accumulated in a fiber type-specific manner in the functionally similar fast-, intermediate- and slow‑twitch gastrocnemius, plantaris, and soleus muscles, respectively, in high-fat diet-induced obese 54-week-old female C57BL/6JOlaHsd mice (n=9) compared to control standard-diet-treated lean mice (n=9). A high-fat diet was administered for 26 weeks. Fiber-type specific intramyocellular lipid content analysis and muscle fiber typing were performed using histochemical analysis of lipids with Sudan Black and immunohistochemical analysis of myosin heavy chains on serial sections of skeletal muscles. Compared to the lean mice, the lipid accumulation was most prominent in types 2a and 2x/d fibers (p<0.05) of fast-twitch gastrocnemius and intermediate plantaris muscles in the obese mice, while in slow-twitch soleus muscle, there was no significant lipid accumulation in the obese animals. Furthermore, the slow-twitch soleus muscle of the obese mice with no significant change in muscle fiber diameters exhibited the most pronounced shift towards fast-type myosin heavy chain isoform expression (p<0.05). In contrast, the fast-twitch and intermediate-twitch gastrocnemius and plantaris muscles, respectively, in which the muscle fiber diameters increased (p<0.05), were more resistant toward myosin heavy chain expression changes. In conclusion, we demonstrated both muscle- and fiber-type specificity in intramyocellular lipid accumulation in obese mice, suggesting that in obesity, similar muscle fiber types in different muscles accumulate lipids differentially.

scholarly journals Cytoskeletal structure of skeletal muscle: identification of an intricate exosarcomeric microtubule lattice in slow- and fast-twitch muscle fibers.

1993 ◽  
Vol 41 (7) ◽  
pp. 1013-1021 ◽  
Author(s):  
S Boudriau ◽  
M Vincent ◽  
C H Côté ◽  
P A Rogers
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Vastus Lateralis ◽  
Muscle Fiber Types ◽  
Vastus Lateralis Muscle ◽  
Type I ◽  
Fiber Types ◽  
Mammalian Skeletal Muscle ◽  
Microtubule Network ◽  
Fast Twitch

We used immunochemical quantification and indirect immunofluorescence to investigate the cell content, distribution, and organization of microtubules in adult rat slow-twitch soleus and fast-twitch vastus lateralis muscles. An immunoblotting assay demonstrated that the soleus muscle (primarily Type I fibers) was found to have a 1.7-fold higher relative content of alpha-tubulin compared with the superficial portion of the vastus lateralis muscle (primarily Type IIb fibers). Both physiological muscle types revealed a complex arrangement of microtubules which displayed oblique, longitudinal, and transverse orientations within the sarcoplasmic space. The predominance of any one particular orientation varied significantly from one muscle tissue section to another. Nuclei were completely surrounded by a dense net-like structure of microtubules. Both muscle fiber types were found to possess a higher density of microtubules in the subsarcolemmal region. These microtubules followed the contour of the sarcolemma in slightly contracted fibers and showed a fine punctate appearance indicative of a restricted distribution. The immunofluorescence results indicate that microtubules are associated with the sarcolemma and therefore may form a part of the membrane cytoskeletal domain of the muscle fiber. We conclude that the microtubule network of the adult mammalian skeletal muscle fiber constitutes a bone fide component of the exosarcomeric cytoskeletal lattice domain along with the intermediate filaments, and as such could therefore participate in the mechanical integration of the various organelles of the myofibers during the contraction-relaxation cycle.

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