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Journal of Bone and Mineral Metabolism

, Volume 22, Issue 1, pp 26–31 | Cite as

Effects of treadmill exercise on bone mass, bone metabolism, and calciotropic hormones in young growing rats

  • Jun IwamotoEmail author
  • Chisato Shimamura
  • Tsuyoshi Takeda
  • Hitoshi Abe
  • Shoichi Ichimura
  • Yoshihiro Sato
  • Yoshiaki Toyama
Article

Abstract

The aim of the present study was to examine the effects of exercise on bone mass, bone metabolism, and calciotropic hormones in young growing rats. Twenty 6-week-old female Wistar rats were randomized into the following four groups with 5 animals each: 7 weeks of exercise, 7 weeks of sedentary control, 11 weeks of exercise, and 11 weeks of sedentary control. The exercise regimen consisted of running on a treadmill at 25 m/min for 1 h each day on 5 days a week. After each period of exercise, the bone mineral content (BMC) of the tibia and fifth lumbar spine was measured by dual-energy X-ray absorptiometry, using a Lunar DPX-L instrument. The femoral length and levels of bone markers and calciotropic hormones were also assessed. Seven and 11 weeks of exercise increased the serum osteocalcin and 1,25-dihydroxyvitamin D3 levels, and decreased the serum parathyroid level. Seven weeks of exercise decreased the urinary deoxypyridinoline level, and 11 weeks of exercise increased the serum alkaline phosphatase level and decreased the serum tartrate-resistant acid phosphatase level. As a result, 7 and 11 weeks of exercise increased the femoral length and tibial BMC, but did not alter the lumbar BMC. The present study demonstrates that treadmill exercise stimulates bone formation and suppresses bone resorption, increases the serum 1,25-dihydroxyvitamin D3 level, and decreases the serum parathyroid hormone level, resulting in an increase in bone mass with stimulation of longitudinal bone growth, especially at weight-bearing sites, in young growing rats. Further studies with long-term exercise may be needed to obtain a positive effect on the lumbar BMC.

Key words

exercise bone mineral content (BMC) bone formation parathyroid hormone vitamin D3 

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Copyright information

© Springer-Verlag Tokyo 2004

Authors and Affiliations

  • Jun Iwamoto
    • 1
    Email author
  • Chisato Shimamura
    • 2
    • 3
  • Tsuyoshi Takeda
    • 1
  • Hitoshi Abe
    • 3
  • Shoichi Ichimura
    • 4
  • Yoshihiro Sato
    • 5
  • Yoshiaki Toyama
    • 2
  1. 1.Department of Sports MedicineKeio University School of MedicineTokyoJapan
  2. 2.Department of Orthopaedic SurgeryKeio University School of MedicineTokyoJapan
  3. 3.Department of Orthopaedic SurgeryKitasato Institute HospitalTokyoJapan
  4. 4.Department of Orthopaedic SurgeryKyorin University School of MedicineTokyoJapan
  5. 5.Department of Rehabilitation MedicineHirosaki University School of MedicineHirosakiJapan

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