The effect of weight-lifting exercise related to muscle fiber composition and muscle cross-sectional area in humans

Muscle fiber numbers were estimated in vivo in biceps brachii in 5 elite male bodybuilders, 7 intermediate caliber bodybuilders, and 13 age-matched controls. Mean fiber area and collagen volume density were calculated from needle biopsies and muscle cross-sectional area by computerized tomographic scanning. Contralateral measurements in a subsample of seven subjects indicated the method for estimation of fiber numbers to have adequate reliability. There was a wide interindividual range for fiber numbers in biceps (172,085–418,884), but despite large differences in muscle size both bodybuilder groups possessed the same number of muscle fibers as the group of untrained controls. Although there was a high correlation between average cross-sectional fiber area and total muscle cross-sectional area within each group, many of the subjects with the largest muscles also tended to have a large number of fibers. Since there were equally well-trained subjects with fewer than normal fiber numbers, we interpret this finding to be due to genetic endowment rather than to training-induced hyperplasia. The proportion of muscle comprised of connective and other noncontractile tissue was the same for all subjects (approximately 13%), thus indicating greater absolute amounts of connective tissue in the trained subjects. We conclude that in humans, heavy resistance training directed toward achieving maximum size in skeletal muscle does not result in an increase in fiber numbers.

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MUSCLE FIBER TYPE DISTRIBUTION, MUSCLE CROSS-SECTIONAL AREA AND SERUM ANDROGENS

Medicine & Science in Sports & Exercise ◽

10.1249/00005768-198315020-00415 ◽

1983 ◽

Vol 15 (2) ◽

pp. 176 ◽

Cited By ~ 1

Author(s):

W. W. Hutchison ◽

P. Schantz ◽

P. -O. Astrand ◽

L. Bevan

Keyword(s):

Muscle Fiber ◽

Fiber Type ◽

Cross Sectional Area ◽

Muscle Fiber Type ◽

Sectional Area ◽

Cross Sectional ◽

Type Distribution ◽

Fiber Type Distribution ◽

Serum Androgens ◽

Muscle Cross Sectional Area

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Jump performance and thigh muscle cross-sectional area in young female rhythmic gymnasts

Gazzetta Medica Italiana Archivio per le Scienze Mediche ◽

10.23736/s0393-3660.18.03698-7 ◽

2019 ◽

Vol 178 (3) ◽

Author(s):

Antonio Cicchella ◽

Monica Mannai ◽

Jaan Ereline ◽

Mati Paasuke ◽

Helena Gapeyeva

Keyword(s):

Young Female ◽

Cross Sectional Area ◽

Thigh Muscle ◽

Sectional Area ◽

Cross Sectional ◽

Jump Performance ◽

Muscle Cross Sectional Area ◽

Rhythmic Gymnasts

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Is there a correlation between upper lumbar disc herniation and multifidus muscle degeneration? A retrospective study of MRI morphology

BMC Musculoskeletal Disorders ◽

10.1186/s12891-021-03970-x ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Chong Liu ◽

Jiang Xue ◽

Jingjing Liu ◽

Gang Ma ◽

Abu Moro ◽

...

Keyword(s):

Lumbar Disc Herniation ◽

Lumbar Disc ◽

Fatty Infiltration ◽

Cross Sectional Area ◽

Sectional Area ◽

Muscle Degeneration ◽

Multifidus Muscle ◽

Cross Sectional ◽

Upper Lumbar Disc Herniation ◽

Muscle Cross Sectional Area

Abstract Background The purpose of the study is to investigate the correlation between upper lumbar disc herniation (ULDH) and multifidus muscle degeneration via the comparison of width, the cross-sectional area and degree of fatty infiltration of the lumbar multifidus muscle. Methods Using the axial T2-weighted images of magnetic resonance imaging as an assessment tool, we retrospectively investigated 132 patients with ULDH and 132 healthy individuals. The total muscle cross-sectional area (TMCSA) and the pure muscle cross-sectional area (PMCSA) of the multifidus muscle at the L1/2, L2/3, and L3/4 intervertebral disc levels were measured respectively, and in the meantime, the average multifidus muscle width (AMMW) and degree of fatty infiltration of bilateral multifidus muscle were evaluated. The resulting data were analyzed to determine the presence/absence of statistical significance between the study and control groups. Multivariate logistical regression analyses were used to evaluate the correlation between ULDH and multifidus degeneration. Results The results of the analysis of the two groups showed that there were statistically significant differences (p < 0.05) between TMCSA, PMCSA, AMMW and degree of fatty infiltration. The multivariate logistic regression analysis indicated that the TMCSA, PMCSA, AMMW and the degree of fatty infiltration of multifidus muscle were correlated with ULDH, and the differences were statistically significant (P < 0.05). Conclusions A correlation could exist between multifidus muscles degeneration and ULDH, that may be a process of mutual influence and interaction. Lumbar muscle strengthening training could prevent and improve muscle atrophy and degeneration.

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