title: Induction of Muscle Hypertrophy in Rats through Low Intensity Eccentric Contraction.
abstract: [Purpose] The purpose of this study was to examine whether a low intensity exercise using an eccentric contraction would result in skeletal muscle hypertrophy in rats. [Subjects and Methods] Eighteen female Wistar rats were used in this study. The rats were randomly divided into three groups. The control group performed no exercise. The level group ran on a treadmill on a 0° incline. The downhill group ran on a treadmill on a -16° incline. The two exercise groups ran on a treadmill at 16 m/min for 90 minutes, once every three days for a total of twenty sessions. [Results] The muscle wet weights, the relative weight ratios, and the muscle fiber cross-section minor axes of the downhill group were significantly larger than those of the control and level groups. There were no differences in the muscle wet weights, the relative weight ratios, and the muscle fiber cross-section minor axes between the control group and the level group. [Conclusion] The stimulation from the low intensity eccentric contraction may have produced enough mechanical stress to induce muscle hypertrophy without the over-stressing that might have produced muscle fiber damage. These results indicate that this technique may be an effective method of inducing hypertrophy in skeletal muscle.
authors.affiliation: Department of Physical Therapy, Faculty of Health and Welfare, Prefectural University of Hiroshima, Japan ; Program in Biological System Sciences, Graduate School of Comprehensive Scientific Research, Prefectural University of Hiroshima, Japan.
authors.forename: Wakako
authors.initials: W
authors.lastname: Tsumiyama
authors.affiliation: Department of Physical Therapy, Faculty of Health and Welfare, Prefectural University of Hiroshima, Japan ; Program in Biological System Sciences, Graduate School of Comprehensive Scientific Research, Prefectural University of Hiroshima, Japan.
authors.forename: Sadaaki
authors.initials: S
authors.lastname: Oki
authors.affiliation: Department of Physical Therapy, Faculty of Health and Welfare, Prefectural University of Hiroshima, Japan.
authors.forename: Naomi
authors.initials: N
authors.lastname: Takamiya
authors.affiliation: Department of Physical Therapy, Faculty of Health and Welfare, Prefectural University of Hiroshima, Japan.
authors.forename: Namiko
authors.initials: N
authors.lastname: Umei
authors.affiliation: Department of Nursing and Rehabilitation, Konan Women's University, Japan.
authors.forename: Michele Eisemann
authors.initials: ME
authors.lastname: Shimizu
authors.affiliation: Department of Physical Therapy, Faculty of Health and Welfare, Prefectural University of Hiroshima, Japan ; Program in Biological System Sciences, Graduate School of Comprehensive Scientific Research, Prefectural University of Hiroshima, Japan.
authors.forename: Takeya
authors.initials: T
authors.lastname: Ono
authors.affiliation: Department of Physical Therapy, Faculty of Health and Welfare, Prefectural University of Hiroshima, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Otsuka
keywords: Eccentric contraction; Low intensity exercise; Muscle hypertrophy