title: Influence of exercise intensity on atrophied quadriceps muscle in the rat.
abstract: [Purpose] The aim of this study was to determine the effect of resistance training on atrophied skeletal muscle in rats based on evidence derived from physical therapy. [Subjects and Methods] Rats were forced to undergo squats as resistance training for 3 weeks after atrophying the rectus femoris muscle by hindlimb suspension for 2 weeks. The intensity of resistance training was adjusted to 50% and 70% of the maximum lifted weight, i.e., 50% of the one-repetition maximum and 70% of the one-repetition maximum, respectively. [Results] Three weeks of training did not alter the one-repetition maximum, and muscle fibers were injured while measuring the one-repetition maximum and reloading. The decrease in cross-sectional area in the rectus femoris muscle induced by unloading for 2 weeks was significantly recovered after training at 70% of the one-repetition maximum. The levels of muscle RING-finger protein-1 mRNA expression were significantly lower in muscles trained at 70% of the one-repetition maximum than in untrained muscles. [Conclusion] These results suggest that high-intensity resistance training can promote atrophic muscle recovery, which provides a scientific basis for therapeutic exercise methods for treatment of atrophic muscle in physical therapy.
authors.affiliation: Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Japan.
authors.forename: Shoji
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Department of Rehabilitation, Kanazawa Nishi Hospital, Japan ; School of Health Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Japan.
authors.forename: Taishi
authors.initials: T
authors.lastname: Obatake
authors.affiliation: Department of Rehabilitation, Mitsugi General Hospital, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Hoshino
authors.affiliation: Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Nakagawa
keywords: Muscle atrophy; Quadriceps muscle; Resistance training