Bones benefits gained by jump training are preserved after detraining in young and adult rats.

We investigated the osteogenic responses to jump training and subsequent detraining in young and adult male rats to test the following hypotheses: 1) jump training has skeletal benefits; 2) these skeletal benefits are preserved with subsequent detraining throughout bone morphometric changes; and 3) there are no differences between young and adult rats during detraining in terms of the maintenance of exercise-induced changes. Twelve-week-old (young) and 44-wk-old (adult) rats were divided into the following four groups: young-sedentary, young-exercised, adult-sedentary, and adult-exercised. The exercised groups performed jump training (height = 40 cm, 10 jumps/day, 5 days/wk) for 8 wk followed by 24 wk of being sedentary.

Effects of jump training on bone are preserved after detraining, regardless of estrogen secretion state in rats.

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-wk-old Wistar rats were divided into the following four groups: sham sedentary (n = 12), sham exercised (n = 11), ovariectomized sedentary (n = 10), and ovariectomized exercised (n = 11). An 8-wk exercise period was introduced in which the rats in the exercised groups were jumped 10 times/day, 5 days/wk.