Association between regional differences in muscle activation in one session of resistance exercise and in muscle hypertrophy after resistance training

Taku Wakahara, Naokazu Miyamoto, Norihide Sugisaki, Koichiro Murata, Hiroaki Kanehisa, Yasuo Kawakami, Tetsuo Fukunaga, Toshimasa Yanai

Research output: Contribution to journalArticle

52 Citations (Scopus)

Abstract

The purpose of this study was to examine if the regional differences in muscle hypertrophy after chronic resistance training is associated with muscle activation after one session of resistance exercise. Twelve men performed one session of resistance exercise of elbow extensors. Before and immediately after the exercise, transverse relaxation time (T2)-weighted magnetic resonance (MR) images of upper arm were recorded to evaluate the muscle activation along its length. In the MR images, T2 for the pixels within the triceps brachii muscle was quantiWed. The number of pixels with T2 greater than the threshold (mean + 1SD of T2 before the exercise) was expressed as the ratio to the number of pixels occupied by the muscle (%activated area). Another 12 subjects completed 12 weeks of training intervention (3 days per week), which consisted of the same program variables as used in the experiment for the T2 measurement. The cross-sectional areas of the triceps brachii before and after the training intervention were measured from MR images of upper arm. The %activated area of the triceps brachii induced by one session of the exercise was found to be signiWcantly lower in the distal region than the middle and proximal regions. Similarly, the relative increase in muscle cross-sectional area after the 12 weeks of training intervention was signiWcantly less in the distal region than the middle and proximal regions. The results suggest that the regional difference in muscle hypertrophy after chronic resistance training is attributable to the regional differences in muscle activation during the exercise.

Original languageEnglish
Pages (from-to)1569-1576
Number of pages8
JournalEuropean Journal of Applied Physiology
Volume112
Issue number4
DOIs
Publication statusPublished - 2012 Apr

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Resistance Training
Hypertrophy
Exercise
Muscles
Magnetic Resonance Spectroscopy
Arm
Elbow

Keywords

  • Cross-sectional area
  • Magnetic resonance image
  • Transverse relaxation time
  • Triceps brachii muscle

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Orthopedics and Sports Medicine
  • Physiology (medical)

Cite this

Association between regional differences in muscle activation in one session of resistance exercise and in muscle hypertrophy after resistance training. / Wakahara, Taku; Miyamoto, Naokazu; Sugisaki, Norihide; Murata, Koichiro; Kanehisa, Hiroaki; Kawakami, Yasuo; Fukunaga, Tetsuo; Yanai, Toshimasa.

In: European Journal of Applied Physiology, Vol. 112, No. 4, 04.2012, p. 1569-1576.

Research output: Contribution to journalArticle

Wakahara, Taku ; Miyamoto, Naokazu ; Sugisaki, Norihide ; Murata, Koichiro ; Kanehisa, Hiroaki ; Kawakami, Yasuo ; Fukunaga, Tetsuo ; Yanai, Toshimasa. / Association between regional differences in muscle activation in one session of resistance exercise and in muscle hypertrophy after resistance training. In: European Journal of Applied Physiology. 2012 ; Vol. 112, No. 4. pp. 1569-1576.
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