title: MRI analysis of structural changes in skeletal muscles and surrounding tissues following long-term walking exercise with training equipment.
abstract: Muscular recovery after exercise is an important topic in sports medicine, and accurate and quantitative measurements of changes in muscle are required to assess muscular recovery. In the present study, we report a new analytical method to measure muscular changes quantitatively. The technique consists of three independent methods: image processing of two-dimensional MR images, morphological analysis using three-dimensional MR images, and diffusion tensor MRI. Using this method, we investigated changes in the quadriceps and biceps femoris and gluteus maximus muscles and surrounding tissues before and after 1 mo of exercise wearing training equipment. The subjects were 21 healthy adult female volunteers, 14 of whom wore training equipment and 7 who wore normal equipment. The percentage of adipose tissue in muscle after exercise in subjects who wore training equipment was on average 4.4% (P < 0.001) lower than that before exercise, and the peak point of the dorsal hip after exercise with use of the equipment was on average 10.8 mm higher than that before exercise. Further, the fractional anisotropy of water diffusion in muscles increased by an average of 0.039 (P < 0.001) after exercise with use of training equipment. In contrast, there was no significant difference before and after exercise in subjects who wore normal equipment. These results show that walking exercise while wearing training equipment thickens and tightens the muscular fiber tissues. This noninvasive measurement approach may allow quantitation of the athletic ability of the muscles, which is not measured conventionally, and is an effective method for analyzing skeletal muscles.
authors.affiliation: Department of Medical Simulation Engineering, Kyoto UNiversity53 Kawahara-cho Syogoin, Sakyo-ku, Kyoto 606-8507, Japan. rnakai@frontier.kyoto-u.ac.jp
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Nakai
authors.forename: Takashi
authors.initials: T
authors.lastname: Azuma
authors.forename: Mai
authors.initials: M
authors.lastname: Sudo
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Urayama
authors.forename: Osamu
authors.initials: O
authors.lastname: Takizawa
authors.forename: Sadami
authors.initials: S
authors.lastname: Tsutsumi
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology; D000328:Adult; D016880:Anisotropy; D001834:Body Water / Q000378:metabolism; D004058:Diffusion; D015444:Exercise / Q000502:physiology*; D005260:Female; D006615:Hip / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D018482:Muscle, Skeletal / Q000033:anatomy & histology* / Q000378:metabolism; D052097:Quadriceps Muscle / Q000033:anatomy & histology; D020127:Recovery of Function; D013997:Time Factors; D016138:Walking