TY - JOUR
T1 - Effects of short-term concentric vs. eccentric resistance training on single muscle fiber MHC distribution in humans
AU - Raue, U.
AU - Terpstra, B.
AU - Williamson, D. L.
AU - Gallagher, P. M.
AU - Trappe, S. W.
PY - 2005/6
Y1 - 2005/6
N2 - 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.
AB - 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.
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U2 - 10.1055/s-2004-821041
DO - 10.1055/s-2004-821041
M3 - Article
C2 - 15895315
AN - SCOPUS:20644464784
SN - 0172-4622
VL - 26
SP - 339
EP - 343
JO - International Journal of Sports Medicine
JF - International Journal of Sports Medicine
IS - 5
ER -