Effect of intensive training on lower leg structural strength: an in vivo study in ovariectomized rats

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Abstract

The aim of this study was to investigate the effect of training on the in vivo tibial structural strength during the development of post-ovariectomy osteoporosis. Seventeen mature Wistar rats (215 g) were ovariectomized and randomized into two groups. The sedentary control group was kept cage confined, while 3 days postoperatively the trained group started treadmill running with high intensity for 1 h 5 days a week. All were given a low calcium diet (Ca 0.01%). After 8 weeks the animals were anaesthetized and the right lower legs fractured during muscle contraction in three-point ventral bending. The left legs were fractured at the same level after removal of all soft tissues. Histomorphometry of the meta- and diaphysis of the distal tibiae was performed. Weight-gain was higher in sedentary (108 g) than in trained (61 g) rats (P<0.0001). There were no significant differences in mechanical results between the groups at in vivo or in vitro fracture. Correcting for weight-gain differences did not change these results. Histomorphometry showed no differences between the groups. Corticosterone was higher in trained than in sedentary rats (P<0.02), and corticosterone may have had a negative influence both on muscle and bone. The study could not show an effect of high intensity training in the early phase after ovariectomy on in vivo or in vitro fracture strength.

Details

Authors
  • T S Kaastad
  • O Reikeras
  • S Narum
  • J E Madsen
  • E Haug
  • Karl Obrant
  • L Nordsletten
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Sport and Fitness Sciences

Keywords

  • exercise, muscle contraction, fractures, osteoporosis, corticosterone, rats
Original languageEnglish
Pages (from-to)220-225
JournalScandinavian Journal of Medicine & Science in Sports
Volume7
Issue number4
Publication statusPublished - 1997
Publication categoryResearch
Peer-reviewedYes