title: Non-uniform decay in jumping exercise-induced bone gains following 12 and 24 weeks of cessation of exercise in rats.
abstract: The effects of deconditioning on exercise-induced bone gains in rats were investigated in 12-week-old female WKY rats performing a standard jumping exercise regimen for either 8, 12 or 24 weeks, followed by sedentary periods of either 24, 12 or 0 weeks, respectively. Age-matched controls received no exercise over the same period. At the end of the training/sedentary period, the tibiae were harvested for analyses of bone parameters. Gains in tibial fat-free dry weight decayed within 12 weeks of deconditioning, but gains in tibial ultimate bending force (strength), maximum diameter and cortical area were still present at 12 weeks of deconditioning. With the exception of cortical area, all other exercise-induced bone gains decayed by the 24th week of deconditioning. It appears that the decay in exercise-induced bone gains in strength, physical and morphological properties is not uniform, and that gains in fat-free dry weight seem to decay earlier.
authors.affiliation: Sports Science Unit, Universiti Sains Malaysia, Kubang Kerian, Malaysia.
authors.forename: Foong-Kiew
authors.initials: FK
authors.lastname: Ooi
authors.forename: Rabindarjeet
authors.initials: R
authors.lastname: Singh
authors.forename: Harbindar Jeet
authors.initials: HJ
authors.lastname: Singh
authors.forename: Yoshohisa
authors.initials: Y
authors.lastname: Umemura
authors.forename: Seigo
authors.initials: S
authors.lastname: Nagasawa
mesh_terms: D000818:Animals; D001835:Body Weight / Q000502:physiology; D015519:Bone Density / Q000502:physiology*; D001846:Bone Development / Q000502:physiology*; D005260:Female; D010805:Physical Conditioning, Animal / Q000379:methods; D010807:Physical Endurance / Q000502:physiology*; D051381:Rats; D011921:Rats, Inbred WKY; D013977:Tibia / Q000378:metabolism / Q000502:physiology*