Non-uniform decay in jumping exercise-induced bone gains following 12 and 24 weeks of cessation of exercise in rats

• Published in: Journal of Physiological Sciences
• Main Author: Ooi F.-K.; Singh R.; Singh H.J.; Umemura Y.; Nagasawa S.
• Format: Article
• Language: English
• Published: 2011
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84855985103&doi=10.1007%2fs12576-011-0169-4&partnerID=40&md5=241f4f4f04ecd998cd4b720ea351015e

The effects of deconditioning on exerciseinduced bone gains in rats were investigated in 12-weekold 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. © The Physiological Society of Japan and Springer 2011.