Gender differences in resistance-training-induced myofiber hypertrophy among older adults.

Full Abstract

We tested the hypothesis that older men (n = 9, 69 +/- 2 years) would experience greater resistance-training-induced myofiber hypertrophy than older women (n = 5, 66 +/- 1 years) following knee extensor training 3 days per week at 65-80% of one-repetition maximum for 26 weeks. Vastus lateralis biopsies were analyzed for myofiber areas, myosin heavy chain isoform distribution, and levels of mRNA for insulin-like growth factor 1 (IGF-1), IGFR1, and myogenin. Gender x Training interactions (p <.05) indicate greater myofiber hypertrophy for all three primary fiber types (I, IIa, IIx) and enhanced one-repetition maximum strength gain in men compared with women (p <.05). Covarying for serum IGF-1, dehydroepiandrosterone sulfate, or each muscle mRNA did not negate these interactions. In both genders, type IIx myofiber area distribution and myosin heavy chain type IIx distribution decreased with a concomitant increase in type IIa myofiber area distribution (p <.05). In summary, gender differences in load-induced myofiber hypertrophy among older adults cannot be explained by levels of circulating IGF-1 or dehydroepiandrosterone sulfate, or by expression of the myogenic transcripts examined.

Learn Faster Today Improve your study skills

Author information

Author/s: Bamman, Marcas M (MM); Hill, Vernishia J (VJ); Adams, Gregory R (GR); Haddad, Fadia (F); Wetzstein, Carla J (CJ); Gower, Barbara A (BA); Ahmed, Ali (A); Hunter, Gary R (GR);

Affiliation: Geriatric Research, Education, and Clinical Center, VA Medical Center, Birmingham, Alabama, USA. mbamman@uab.edu

Grants: R01 AG-17896 (Agency:United States NIA) ; R01 AR-45594 (Agency:United States NIAMS)

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.

Journal: The journals of gerontology. Series A, Biological sciences and medical sciences (J Gerontol A Biol Sci Med Sci), published in United States. (Language: eng)

Reference: 2003-Feb; vol 58 (issue 2) : pp 108-16

Dates: Created 2003/02/14; Completed 2003/03/06; Revised 2007/11/14;

PMID: 12586847, status: MEDLINE (last retrieval date: 11/6/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

External Links for this article (including full text providers, if available):

Click Electronic Full-text Provider Links to see options for finding the electronic full text links to this article. Note there may be a subscription or fee required for access to the full text. See our FAQ for information on finding FREE full text articles.

This article may also be located in paper journal collections available in many libraries. Use the Journal and Publication Information above to find the full article.

MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Aged
Analysis of Variance
Body Composition - physiology
Body Mass Index
Cohort Studies
Exercise
Female
Humans
Immunohistochemistry
Insulin-Like Growth Factor I - analysis; metabolism

Insulin-Like Growth Factor I - analysis; metabolism
Male
Middle Aged
Muscle Fibers - metabolism; physiology
Muscle, Skeletal - anatomy & histology; physiology
Myogenin - analysis; metabolism
Physical Education and Training
Reference Values
Sensitivity and Specificity
Sex Factors

Associated Chemicals: MYOG protein, human (0) ; Myogenin (0) ; Insulin-Like Growth Factor I (67763-96-6)

This article has not been indexed for related articles as yet, however you can still use the live related article search links below.

See 100+ related articles.