Effects of Short-Term Concentric vs. Eccentric Resistance Training on Single Muscle Fiber MHC Distribution in Humans
The purpose of this investigation was to determine the effects of a concentric vs. eccentric resistance training program on single muscle fiber myosin heavy chain (MHC) adaptations in humans. Fifteen sedentary, healthy males were divided into three groups: concentric training (CTG) (n = 6, 24.2 ± 1.7 y, 181 ± 2 cm, 82.5 ± 4.6 kg), eccentric training (ETG) (n = 6, 23.7 ± 1.6 y, 178 ± 3 cm, 90.4 ± 6.1 kg), and control (CTL) (n = 3, 23 ± 1.5 y, 181 ± 2 cm, 97 ± 13.2 kg). The subjects performed 4 sets of 8 unilateral repetitions starting at 80 % of concentric 1-RM, 3 days/week for a total of 4 weeks. Subjects were tested pre- and post-training for concentric 1-RM. Muscle biopsies were obtained from the vastus lateralis pre- and post-training for determination of single fiber MHC isoform distribution using SDS-PAGE/silver staining (100 fibers analyzed/subject pre- and post-training). Fibers expressing more than one MHC isoform (i.e., hybrid fibers) were analyzed for relative MHC isoform proportions via densitometry. The training program resulted in a 19 % 1-RM strength gain for CTG (p < 0.05) with no change in ETG or CTL. MHC-IIx fibers decreased by 7 % in CTG (p < 0.05) and ETG had an 11 % increase in total hybrids (MHC-I/IIa + MHC-IIa/IIx) (p < 0.05). No other differences were noted in MHC distribution among the three groups. Densitometry analysis of hybrid fibers showed no change in relative MHC isoform proportions pre- to post-training for any group. These data suggest that the MHC distribution did not change dramatically as a result of 4 weeks of concentric vs. eccentric resistance training despite the increase in whole muscle strength from concentric muscle actions..
| Medienart: |
E-Artikel |
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| Erscheinungsjahr: |
2005 |
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| Erschienen: |
Stuttgart: Georg Thieme Verlag ; 2005 |
| Reproduktion: |
Thieme Zeitschriftenarchive 1980-2007 |
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| Enthalten in: |
Zur Gesamtaufnahme - volume:26 |
| Enthalten in: |
International journal of sports medicine - 26(2005), 05 vom: Juni, Seite 339-343 |
| Sprache: |
Englisch |
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| Beteiligte Personen: |
Raue, U. [VerfasserIn] |
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| Links: |
dx.doi.org [Deutschlandweit zugänglich] |
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| Themen: |
Fiber type |
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| Umfang: |
5 |
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| doi: |
10.1055/s-2004-821041 |
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| funding: |
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| Förderinstitution / Projekttitel: |
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| PPN (Katalog-ID): |
NLEJ226256995 |
|---|
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| 245 | 1 | 0 | |a Effects of Short-Term Concentric vs. Eccentric Resistance Training on Single Muscle Fiber MHC Distribution in Humans |
| 264 | 1 | |a Stuttgart ; New York |b Georg Thieme Verlag |c 2005 | |
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| 520 | |a The purpose of this investigation was to determine the effects of a concentric vs. eccentric resistance training program on single muscle fiber myosin heavy chain (MHC) adaptations in humans. Fifteen sedentary, healthy males were divided into three groups: concentric training (CTG) (n = 6, 24.2 ± 1.7 y, 181 ± 2 cm, 82.5 ± 4.6 kg), eccentric training (ETG) (n = 6, 23.7 ± 1.6 y, 178 ± 3 cm, 90.4 ± 6.1 kg), and control (CTL) (n = 3, 23 ± 1.5 y, 181 ± 2 cm, 97 ± 13.2 kg). The subjects performed 4 sets of 8 unilateral repetitions starting at 80 % of concentric 1-RM, 3 days/week for a total of 4 weeks. Subjects were tested pre- and post-training for concentric 1-RM. Muscle biopsies were obtained from the vastus lateralis pre- and post-training for determination of single fiber MHC isoform distribution using SDS-PAGE/silver staining (100 fibers analyzed/subject pre- and post-training). Fibers expressing more than one MHC isoform (i.e., hybrid fibers) were analyzed for relative MHC isoform proportions via densitometry. The training program resulted in a 19 % 1-RM strength gain for CTG (p < 0.05) with no change in ETG or CTL. MHC-IIx fibers decreased by 7 % in CTG (p < 0.05) and ETG had an 11 % increase in total hybrids (MHC-I/IIa + MHC-IIa/IIx) (p < 0.05). No other differences were noted in MHC distribution among the three groups. Densitometry analysis of hybrid fibers showed no change in relative MHC isoform proportions pre- to post-training for any group. These data suggest that the MHC distribution did not change dramatically as a result of 4 weeks of concentric vs. eccentric resistance training despite the increase in whole muscle strength from concentric muscle actions. | ||
| 533 | |f Thieme Zeitschriftenarchive 1980-2007 | ||
| 650 | 4 | |a strength training | |
| 650 | 4 | |a myosin heavy chain | |
| 650 | 4 | |a Skeletal muscle | |
| 650 | 4 | |a fiber type | |
| 700 | 1 | |a Terpstra, B. |e verfasserin |4 aut | |
| 700 | 1 | |a Williamson, D. L. |e verfasserin |4 aut | |
| 700 | 1 | |a Gallagher, P. M. |4 oth | |
| 700 | 1 | |a Trappe, S. W. |4 oth | |
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