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Aging, muscle fiber...
Aging, muscle fiber type, and contractile function in sprint-trained athletes
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Korhonen, Marko (författare)
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- Cristea, Alexander (författare)
- Uppsala universitet,Klinisk neurofysiologi
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Alén, Markku (författare)
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Häkkinen, Keijo (författare)
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Sipilä, Sarianna (författare)
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Mero, Antti (författare)
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Viitasalo, Jukka (författare)
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- Larsson, Lars (författare)
- Uppsala universitet,Klinisk neurofysiologi
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Suominen, Harri (författare)
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(creator_code:org_t)
- American Physiological Society, 2006
- 2006
- Engelska.
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Ingår i: Journal of applied physiology. - : American Physiological Society. - 8750-7587 .- 1522-1601. ; 101:3, s. 906-917
- Relaterad länk:
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https://urn.kb.se/re...
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visa fler...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- Biopsy samples were taken from the vastus lateralis of 18- to 84-yr-old male sprinters (n = 91). Fiber-type distribution, cross-sectional area, and myosin heavy chain (MHC) isoform content were identified using ATPase histochemistry and SDS-PAGE. Specific tension and maximum shortening velocity (V-o) were determined in 144 single skinned fibers from younger (18-33 yr, n = 8) and older (53-77 yr, n = 9) runners. Force-time characteristics of the knee extensors were determined by using isometric contraction. The cross-sectional area of type I fibers was unchanged with age, whereas that of type II fibers was reduced (P < 0.001). With age there was an increased MHC I (P < 0.01) and reduced MHC IIx isoform content (P < 0.05) but no differences in MHC IIa. Specific tension of type I and IIa MHC fibers did not differ between younger and older subjects. V-o of fibers expressing type I MHC was lower (P < 0.05) in older than in younger subjects, but there was no difference in V-o of type IIa MHC fibers. An aging-related decline of maximal isometric force (P < 0.001) and normalized rate of force development (P < 0.05) of knee extensors was observed. Normalized rate of force development was positively associated with MHC II (P < 0.05). The sprint-trained athletes experienced the typical aging-related reduction in the size of fast fibers, a shift toward a slower MHC isoform profile, and a lower V-o of type I MHC fibers, which played a role in the decline in explosive force production. However, the muscle characteristics were preserved at a high level in the oldest runners, underlining the favorable impact of sprint exercise on aging muscle.
Nyckelord
- exercise
- myosin heavy chain
- single-fiber contractile properties
- muscle strength
- MEDICINE
- MEDICIN
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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