Muscle fiber number in the biceps brachii muscle of young and old men

2003 ◽  
Vol 28 (1) ◽  
pp. 62-68 ◽  
Author(s):  
Cliff S. Klein ◽  
Greg D. Marsh ◽  
Robert J. Petrella ◽  
Charles L. Rice
Keyword(s):  
Muscle Fiber ◽  
Biceps Brachii ◽  
Biceps Brachii Muscle ◽  
Fiber Number ◽  
Muscle Fiber Number ◽  
Old Men

Estimation of skeletal muscle fiber number by mean fiber dry weight

1984 ◽  
Vol 56 (1) ◽  
pp. 244-247
Author(s):  
B. F. Timson ◽  
G. A. Dudenhoeffer
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Biceps Brachii ◽  
Estimation Method ◽  
Dry Weight ◽  
Skeletal Muscle Fiber ◽  
Anterior Latissimus Dorsi ◽  
Fiber Number ◽  
Nitric Acid Digestion ◽  
Muscle Fiber Number

The purpose of this study was to determine whether skeletal muscle fiber number could be accurately estimated by the determination of mean fiber dry weight (MFD) and total muscle dry weight. The muscles studied were the soleus, plantaris, gastrocnemius, extensor digitorum longus, tibialis anterior, and biceps brachii of the rat, the anterior latissimus dorsi of the chicken, and the flexor carpi radialis of the cat. Bundles of fibers were carefully separated from the muscle following nitric acid digestion (ND) and placed in groups of similar length. MFD determined from 400 to 800 fibers from each group was used to estimate the number of fibers in the remainder of the group. Estimated fiber number was compared with the fiber number determined in the muscle from the contralateral limb by the ND method. No difference in fiber number was observed between the ND method and the MFD estimation method for any of the muscles used in the study. The results indicate that the MFD estimation method is an accurate and relatively rapid method of fiber number determination in skeletal muscle.

Voluntary strength and muscle characteristics in untrained men and women and male bodybuilders

1987 ◽  
Vol 62 (5) ◽  
pp. 1786-1793 ◽  
Author(s):  
D. G. Sale ◽  
J. D. MacDougall ◽  
S. E. Alway ◽  
J. R. Sutton
Keyword(s):  
Muscle Fiber ◽  
Biceps Brachii ◽  
Peak Torque ◽  
Volume Density ◽  
Isokinetic Dynamometer ◽  
Cross Sectional ◽  
Fiber Area ◽  
Fiber Composition ◽  
Fiber Number ◽  
Voluntary Strength

Eight untrained women (F), 13 untrained men (M), and 11 male bodybuilders (BB) did maximal elbow flexions on an isokinetic dynamometer at velocities of 30, 120, 180, 240, and 300 degrees/s, from which impact torque (IT), peak torque (PT), and work (W) were measured. Biceps and total flexor cross-sectional area (CSA) were measured by computerized tomographic scanning. Muscle fiber area, fiber composition, and collagen volume density were determined from single needle biopsies of biceps brachii. Biceps fiber number was estimated as the ratio of biceps CSA (corrected for connective tissue) to mean fiber area. PT and W decreased at higher velocities in M and BB but not in F; consequently, the correlation between CSA and PT and W was lower at 300 degrees/s (r = 0.58, 0.60) than 30 degrees/s (r = 0.80, 0.79). The ratio of PT to flexor CSA was similar in all groups at 30 degrees/s, whereas F had greater ratios than M and BB at the remaining velocities. F had greater W/CSA ratios than M and BB at all velocities. IT increased at higher velocities in all groups; the increase was greater in F and M than in BB. In contrast to PT and W, the correlation between IT and CSA was greater at 300 degrees/s (r = 0.67) than 30 degrees/s (r = 0.58), and there were no differences among groups in the IT/CSA ratios. Flexor CSA correlated negatively with the ratio of IT, PT, and W to CSA. Muscle fiber composition failed to correlate with any measure of strength. M and BB had greater biceps area, fiber number, and fiber area than F.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Evaluation of Myosin Heavy Chain Isoforms in Biopsied Longissimus Thoracis Muscle for Estimation of Meat Quality Traits in Live Pigs

Animals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 9
Author(s):  
Min Young Park ◽  
Youn-Chul Ryu ◽  
Chung-Nam Kim ◽  
Kyung-Bo Ko ◽  
Jun-Mo Kim
Keyword(s):  
Myosin Heavy Chain ◽  
Meat Quality ◽  
Muscle Fiber ◽  
Heavy Chain ◽  
Rapid Identification ◽  
Poor Quality ◽  
Myosin Heavy Chain Isoforms ◽  
Type I ◽  
Fiber Number ◽  
Muscle Fiber Number

Estimating meat quality prior to slaughter will be beneficial for the rapid identification of specific traits or poor quality pork compared to a conventional assessment at postmortem. In this study, we identified and quantified myosin heavy chain (MHC) isoforms from a biopsied longissimus thoracis muscle of pigs, and determined their correlation with postmortem muscle fiber characteristics and meat quality. MHC slow and fast isoforms proportions from biopsied samples correlated with postmortem percentage of type I and type IIB muscle fibers, respectively (p < 0.05). The percentage of the biopsied MHC slow isoform showed a positive correlation with pH at 45 min postmortem, and negative correlations with filter-paper fluid uptake and drip loss in pork (p < 0.05). Furthermore, clustering the pigs into three groups based on the biopsied MHC isoform proportions was not only significantly associated with muscle fiber number and proportions of muscle fiber area, but also correlated with pH at 45 min postmortem and the National Pork Producers Council color score (p < 0.05). Collectively, our findings indicate that the biopsied MHC isoforms serve as parameter for estimating meat quality, with the association between the higher proportion of MHC slow isoforms and pH at 45 min postmortem in particular being indicative of better pork quality.

scholarly journals Endocrine regulation of fetal skeletal muscle growth: impact on future metabolic health

2014 ◽  
Vol 221 (2) ◽  
pp. R13-R29 ◽  
Author(s):  
Laura D Brown
Keyword(s):  
Skeletal Muscle ◽  
Muscle Mass ◽  
Muscle Fiber ◽  
Muscle Growth ◽  
Metabolic Health ◽  
Endocrine Regulation ◽  
Intrauterine Environment ◽  
Skeletal Muscle Growth ◽  
Fiber Number ◽  
Muscle Fiber Number

Establishing sufficient skeletal muscle mass is essential for lifelong metabolic health. The intrauterine environment is a major determinant of the muscle mass that is present during the life course of an individual, because muscle fiber number is set at the time of birth. Thus, a compromised intrauterine environment from maternal nutrient restriction or placental insufficiency that restricts muscle fiber number can have permanent effects on the amount of muscle an individual will live with. Reduced muscle mass due to fewer muscle fibers persists even after compensatory or ‘catch-up’ postnatal growth occurs. Furthermore, muscle hypertrophy can only partially compensate for this limitation in fiber number. Compelling associations link low birth weight and decreased muscle mass to future insulin resistance, which can drive the development of the metabolic syndrome and type 2 diabetes, and the risk of cardiovascular events later in life. There are gaps in knowledge about the origins of reduced muscle growth at the cellular level and how these patterns are set during fetal development. By understanding the nutrient and endocrine regulation of fetal skeletal muscle growth and development, we can direct research efforts toward improving muscle growth early in life to prevent the development of chronic metabolic diseases later in life.

scholarly journals Cell death regulates muscle fiber number

2016 ◽  
Vol 415 (1) ◽  
pp. 87-97 ◽  
Author(s):  
Tatevik Sarkissian ◽  
Richa Arya ◽  
Seda Gyonjyan ◽  
Barbara Taylor ◽  
Kristin White
Keyword(s):  
Cell Death ◽  
Muscle Fiber ◽  
Fiber Number ◽  
Muscle Fiber Number

Hormone-sensitive stages in the sexual differentiation of laryngeal muscle fiber number in Xenopus laevis

Development ◽  
1990 ◽  
Vol 110 (3) ◽  
pp. 703-711 ◽  
Author(s):  
M.L. Marin ◽  
M.L. Tobias ◽  
D.B. Kelley
Keyword(s):  
Xenopus Laevis ◽  
Muscle Fiber ◽  
Muscle Fibers ◽  
Laryngeal Muscle ◽  
African Clawed Frog ◽  
Fiber Number ◽  
Hormone Sensitive ◽  
Muscle Fiber Number ◽  
Clawed Frog ◽  
Fiber Addition

The number of muscle fibers in the vocal organ of the adult male African clawed frog, Xenopus laevis, exceeds that of adult females. This sex difference is the result of rapid fiber addition in males between the end of metamorphosis, post-metamorphic stage 0 (PM0) and PM2. At PM0, male and female frogs have similar numbers of laryngeal muscle fibers. Males then add more muscle fibers than females and achieve an adult value that is 1.7 times the female number. Males castrated at PM0 have the same fiber number as females. Ovariectomy at PM0 does not alter muscle fiber addition in females. Gonadectomy at PM2 has no effect on fiber addition in either sex. Females attain masculine muscle fiber number if their ovaries are replaced with a testis at metamorphosis. Exogenous testosterone treatment at PM0 significantly increases fiber number in females but not in males. Exogenous testosterone given at PM2 has no effect on fiber number in females but decreases fiber number in males. We conclude that the testes are necessary for the marked addition of laryngeal muscle fibers seen in male X. laevis between PM0 and PM2. The masculine pattern of muscle fiber addition can be induced in females provided with a testis. Androgen secretion from the testes most probably accounts for masculinization of laryngeal muscle fiber number. After PM2, androgens are no longer necessary for muscle fiber addition and cannot increase fiber number in females.

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