The osteogenic effects of swimming, jumping, and vibration on the protection of bone quality from disuse bone loss.

We assessed and compared the effects of swimming, jumping, and vibration therapies on the prevention of bone loss because of unloading. Eighty Wistar rats were randomly divided into eight groups: S, permanent hind limb-suspended rats; CON, control rats; S + Swim, unloading interrupted by swimming exercise; S + C(Swim), suspension interrupted by regular weight-bearing with the same duration as in the S + Swim protocol; S + Jump, unloading interrupted by jumping exercise; S + C(Jump), suspension interrupted for regular weight-bearing as in the S + Jump group; S + Vibr, unloading interrupted by vibration; and S + C(Vibr), suspension with interruptions for regular weight-bearing with the same protocol as that used for the S + Vibr rats. At the end of the experiment, the bone mineral density, bone strength, histomorphometric parameters, and serum levels of the bone markers were analyzed. The hind limb-suspended rats exhibited bone quality loss. In contrast, the trained rats showed a significant increase in bone mass, bone strength, bone formation, and serum levels of bone markers compared with the respective controls. Although we did not find a significant difference among the three physical exercises, the osteogenic effect of vibration was slightly lower than that of swimming and jumping. Thus, all physical exercises were efficient in preventing bone loss because of unloading and preserving bone quality.

Effect of treadmill exercise on lumbar vertebrae in ovariectomized rats: anthropometrical and mechanical analyses.

The purpose of this study was to examine the preventive effect of exercise on lumbar vertebrae in ovariectomized rats. Three-month-old female Wistar rats were divided into 3 groups: control group (A, n = 10); non-exercised ovariectomized group (B, n = 7) and exercised ovariectomized group (C, n = 7). The rats from group C were subjected to treadmill exercise (15 m/minute in the initial six weeks and 19 m/minute in the next six weeks, 1 hour/day, 4 days/week) for 12 weeks. At death, the fourth lumbar vertebrae were removed and an anthropometrical analysis by a paquimeter and a mechanical compression test by a universal test machine were performed. After 12 weeks, the ovariectomy decreased the superior-inferior vertebral height and the maximal braking load in group B compared to group A, while the exercise increased the vertebral mass in group C compared to both groups A and B (rho< 0.01) and the stiffness compared to group B. We concluded the physical activity has an important role to prevent the osteopenia in lumbar vertebrae.