Cycling exercise-induced myofiber transitions in skeletal muscle depend on basal fiber type distribution

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Cycling exercise-induced myofiber transitions in skeletal muscle depend on basal fiber type distribution. / Weber, Sarah; Weidmann, Bente; Gutsche, Katrin; Platen, Petra; Graf, Christine; Kappes-Horn, Karin; Bloch, Wilhelm; Gehlert, Sebastian.

in: European journal of applied physiology, Jahrgang 112, Nr. 7, 01.07.2012, S. 2393-2402.

Publikationen: Beitrag in FachzeitschriftZeitschriftenaufsätzeForschungBegutachtung

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@article{a0a6bba91d914bebbd063a364485e8f4,
title = "Cycling exercise-induced myofiber transitions in skeletal muscle depend on basal fiber type distribution",
abstract = "The link between specific changes in myofiber type proportions and modulation of training in human skeletal muscle has yet to be unraveled. We investigated whether a defined increase in training volume induces a corresponding change of myofiber shifting in human skeletal muscle with distinct basal myofiber distribution. Twenty-one male cyclists (Age 26 ± 4 years) with different performance levels were exposed to increased cycling training volume with reduced power output for 3 months. Biopsies were taken from vastus lateralis muscle PRE-POST and the proportions of type I, IIa, IIx and IIc myofibers were determined. Total training time did not correlate to the degree of fiber type shifting of any type. In the entire sample of subjects, the proportion of type I myofibers tended to increase (P = 0.14) while IIa fibers decreased significantly (P < 0.05). Subgroups of subjects possessing higher (HPS) and lower proportions (LPS) of type I myofibers at baseline showed a distinct pattern in changing myofiber distribution. Subjects in HPS offered no change in myofiber proportions of any type. In contrast, subjects in LPS showed marked increases in type I (P = 0.06) and a significant reduction in IIa myofibers (P = 0.01). An inverse correlation between baseline proportion of type I and IIa myofibers and its change was observed. We conclude that individual myofiber composition constitutes a modulating factor for exercise-induced changes in its distribution. This might be influenced by altered demands of myofiber recruitment in relation to the intensity of muscle contraction but also by its relative abundance in contracting muscle.",
keywords = "Adaptation, Physiological, Adult, Bicycling, Exercise, Humans, Male, Muscle Fibers, Skeletal, Physical Fitness, Thigh",
author = "Sarah Weber and Bente Weidmann and Katrin Gutsche and Petra Platen and Christine Graf and Karin Kappes-Horn and Wilhelm Bloch and Sebastian Gehlert",
year = "2012",
month = "7",
day = "1",
doi = "10.1007/s00421-011-2209-4",
language = "English",
volume = "112",
pages = "2393--2402",
journal = "European journal of applied physiology",
issn = "1439-6319",
publisher = "Springer Verlag",
number = "7",

}

RIS

TY - JOUR

T1 - Cycling exercise-induced myofiber transitions in skeletal muscle depend on basal fiber type distribution

AU - Weber, Sarah

AU - Weidmann, Bente

AU - Gutsche, Katrin

AU - Platen, Petra

AU - Graf, Christine

AU - Kappes-Horn, Karin

AU - Bloch, Wilhelm

AU - Gehlert, Sebastian

PY - 2012/7/1

Y1 - 2012/7/1

N2 - The link between specific changes in myofiber type proportions and modulation of training in human skeletal muscle has yet to be unraveled. We investigated whether a defined increase in training volume induces a corresponding change of myofiber shifting in human skeletal muscle with distinct basal myofiber distribution. Twenty-one male cyclists (Age 26 ± 4 years) with different performance levels were exposed to increased cycling training volume with reduced power output for 3 months. Biopsies were taken from vastus lateralis muscle PRE-POST and the proportions of type I, IIa, IIx and IIc myofibers were determined. Total training time did not correlate to the degree of fiber type shifting of any type. In the entire sample of subjects, the proportion of type I myofibers tended to increase (P = 0.14) while IIa fibers decreased significantly (P < 0.05). Subgroups of subjects possessing higher (HPS) and lower proportions (LPS) of type I myofibers at baseline showed a distinct pattern in changing myofiber distribution. Subjects in HPS offered no change in myofiber proportions of any type. In contrast, subjects in LPS showed marked increases in type I (P = 0.06) and a significant reduction in IIa myofibers (P = 0.01). An inverse correlation between baseline proportion of type I and IIa myofibers and its change was observed. We conclude that individual myofiber composition constitutes a modulating factor for exercise-induced changes in its distribution. This might be influenced by altered demands of myofiber recruitment in relation to the intensity of muscle contraction but also by its relative abundance in contracting muscle.

AB - The link between specific changes in myofiber type proportions and modulation of training in human skeletal muscle has yet to be unraveled. We investigated whether a defined increase in training volume induces a corresponding change of myofiber shifting in human skeletal muscle with distinct basal myofiber distribution. Twenty-one male cyclists (Age 26 ± 4 years) with different performance levels were exposed to increased cycling training volume with reduced power output for 3 months. Biopsies were taken from vastus lateralis muscle PRE-POST and the proportions of type I, IIa, IIx and IIc myofibers were determined. Total training time did not correlate to the degree of fiber type shifting of any type. In the entire sample of subjects, the proportion of type I myofibers tended to increase (P = 0.14) while IIa fibers decreased significantly (P < 0.05). Subgroups of subjects possessing higher (HPS) and lower proportions (LPS) of type I myofibers at baseline showed a distinct pattern in changing myofiber distribution. Subjects in HPS offered no change in myofiber proportions of any type. In contrast, subjects in LPS showed marked increases in type I (P = 0.06) and a significant reduction in IIa myofibers (P = 0.01). An inverse correlation between baseline proportion of type I and IIa myofibers and its change was observed. We conclude that individual myofiber composition constitutes a modulating factor for exercise-induced changes in its distribution. This might be influenced by altered demands of myofiber recruitment in relation to the intensity of muscle contraction but also by its relative abundance in contracting muscle.

KW - Adaptation, Physiological

KW - Adult

KW - Bicycling

KW - Exercise

KW - Humans

KW - Male

KW - Muscle Fibers, Skeletal

KW - Physical Fitness

KW - Thigh

U2 - 10.1007/s00421-011-2209-4

DO - 10.1007/s00421-011-2209-4

M3 - Journal articles

VL - 112

SP - 2393

EP - 2402

JO - European journal of applied physiology

T2 - European journal of applied physiology

JF - European journal of applied physiology

SN - 1439-6319

IS - 7

ER -

ID: 65801