title: Effects of physical training on cortical bone at midtibia assessed by peripheral QCT.
abstract: Effects of long-term exercise on volumetric bone mineral density (vBMD), bone mineral content, bone geometric properties, and the strength indexes of bone were examined in a cross-sectional study of athletes and controls. Tibias of 25 jumpers (13 women), 30 swimmers (15 women), and 25 controls (15 women), aged 18-23 yr, were scanned at midsite by using peripheral quantitative computed tomography. The cortical vBMD of female athletes was lower than that of the controls (2.00 +/- 0.05, 1.90 +/- 0.08, and 1.92 +/- 0.12 g/cm3, respectively, for controls, swimmers, and jumpers). On the other hand, periosteal areas of male jumpers and female athletes were greater than that of controls (460 +/- 50, 483 +/- 46, and 512 +/- 55 mm2, respectively, for male controls, swimmers, and jumpers, and 283 +/- 52, 341 +/- 73, and 378 +/- 75 mm2, respectively, for female controls, swimmers, and jumpers). The endocortical area of female swimmers was greater than that of controls (103 +/- 29, 148 +/- 52, and 135 +/- 54 mm2, respectively, for controls, swimmers, and jumpers). The polar moment of inertia and strength strain index of male jumpers and female athletes were significantly greater than those of controls, except for the difference in strength strain index between male jumpers and controls. We conclude that the improvement of mechanical properties of young adult bone in response to long-term exercise is related to geometric adaptation and not to vBMD.
authors.affiliation: Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8574, Japan.
authors.forename: LiJing
authors.initials: L
authors.lastname: Liu
authors.forename: Ryouko
authors.initials: R
authors.lastname: Maruno
authors.forename: Tomoko
authors.initials: T
authors.lastname: Mashimo
authors.forename: Kazunori
authors.initials: K
authors.lastname: Sanka
authors.forename: Tai
authors.initials: T
authors.lastname: Higuchi
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Hayashi
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Shirasaki
authors.forename: Naoki
authors.initials: N
authors.lastname: Mukai
authors.forename: Shinichi
authors.initials: S
authors.lastname: Saitoh
authors.forename: Kumpei
authors.initials: K
authors.lastname: Tokuyama
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D000328:Adult; D001696:Biomechanical Phenomena; D015519:Bone Density; D001842:Bone and Bones / Q000000981:diagnostic imaging / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D010809:Physical Fitness / Q000502:physiology*; D013550:Swimming / Q000502:physiology; D013977:Tibia / Q000000981:diagnostic imaging / Q000502:physiology; D014057:Tomography, X-Ray Computed; D014142:Track and Field / Q000502:physiology