“…In animal models of disuse, traditionally in rats, hindlimb immobilization has been found to induce a drastic and sudden loss of femoral bone tissue, suggesting that dif-ferent mechanisms may be involved in disuse-related (fast bone loss) vs. age-related osteoporosis (slow bone loss; Bagi and Miller, 1994). For instance, a 10-30% (up to 50% after 18 months) decrease of cancellous bone was found within a few weeks in the ipsilateral femur of rats that had their hindlimbs immobilized with a cast or an elastic bandage (Li et al, 1990;Chen et al, 1992;Maeda et al, 1993). Some of the changes associated with disuse are believed to be mediated by both an increase of osteoclastic bone resorption and a decrease of osteoblastic bone formation (Rantakokko et al, 1999;Kingery et al, 2003).…”