OXIDATIVE CAPACITY OF HUMAN MUSCLE-FIBER TYPES - EFFECTS OF AGE AND TRAINING STATUS

Title

OXIDATIVE CAPACITY OF HUMAN MUSCLE-FIBER TYPES - EFFECTS OF AGE AND TRAINING STATUS

Creator

Proctor D N; Sinning W E; Walro J M; Sieck G C; Lemon P W R

Publisher

Journal of Applied Physiology

Date

1995
1995-06

Description

Morphometry and oxidative capacity of slow-twitch (type I) and fast-twitch (type IIa and IIb) muscle fibers obtained from vastus lateralis needle biopsies were compared between younger (21-30 yr) and older (51-62 yr) normal fit (maximal O-2 uptake = 47.0 vs. 32.3 ml . kg(-1) . min(-1)) and endurance-trained (66.3 vs. 52.7 ml . kg(-1) . min(-1)) men (n = 6/group). The older groups had smaller type IIa (31%) and IIb (40%) fiber areas and fewer capillaries surrounding these fibers than did younger groups. The reduced type II fiber areas and capillary contacts associated with aging were also observed in the older trained men. However, the capillary supply per unit type II fiber area was not affected by age but was enhanced by training. Additionally, on the basis of quantitative histochemical analysis, succinate dehydrogenase activities of type IIa fibers in the older trained men [4.07 +/- 0.68 (SD) mmol . min(-1) . l(-1)] were similar to those observed in younger trained men (4.00 +/- 0.48 mmol . min(-1) . l(-1)) and twofold higher than in older normal fit men (2.01 +/- 0.65 mmol . min(-1) . l(-1); age x fitness interaction, P < 0.05). Type I muscle fibers were unaffected by age but were larger and had more capillary contacts and higher succinate dehydrogenase activities in the trained groups. The findings of this study suggest that aging results in a decrease in type II fiber size and oxidative capacity in healthy men and that this latter effect can be prevented by endurance training. Conclusions regarding the effects of age and training status on muscle capillarization depend largely on how these data are expressed.

Subject

capillarization; elderly men; human skeletal-muscle; master athletes; maximal oxygen uptake; metabolism; morphology; muscle atrophy; Physiology; quantitative histochemistry; size; Sport Sciences; succinate dehydrogenase; vo2max; women; young

Identifier

n/a

Format

Journal Article

URL Address

n/a

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Rights

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

Pages

2033-2038

Issue

6

Volume

78

Citation

Proctor D N; Sinning W E; Walro J M; Sieck G C; Lemon P W R, “OXIDATIVE CAPACITY OF HUMAN MUSCLE-FIBER TYPES - EFFECTS OF AGE AND TRAINING STATUS,” NEOMED Bibliography Database, accessed June 16, 2021, https://neomed.omeka.net/items/show/7826.

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