We investigated whether the effects of jump training on bone are preserved after a detraining period in female normal and estrogen-deficient rats. Forty-four 11-week-old Wistar rats were divided into the following 4 groups: Sham-Sedentary (n=12), Sham-Exercised (n=11), Ovariectomized-Sedentary (n=10), and Ovariectomized- Exercised (n=11). An 8-week exercise period was introduced in which the rats in the exercised groups were jumped 10 times/day, 5 days/week. This was followed by 24 weeks of detraining. At the end of the exercise period, the jump training significantly increased the bone mineral content (BMC) of the tibia (p < 0.001) measured by dual-energy X-ray absorptiometry (DXA). After the detraining period, the BMC (p < 0.01), strength (p < 0.001) and cross-sectional widths (p < 0.001) of the tibia in the exercised groups were still greater than in the sedentary groups, without significant surgery-exercise interactions, although bone stiffness in the fracture test (p < 0.05) and bone area in the center-proximal region as measured by DXA (p < 0.05) showed significant surgery-exercise interactions. These findings suggest that the exercise effect on bone strength is preserved, accompanied by cross-sectional morphological changes, even under estrogen deficiency.