Objectives:To assess and compare the influence of exercise, calcium and estrogen on biomechanics of femurs in ovariectomized rats. Material and Method: Nine groups were established: (1)Normal Control group;(2)Osteoporosis model(OVX), (3)Combined Exercise and Calcium (Ex-Ca group); (4)Exercise-1 group;(5)Exercise-2 group;(6)Exercise Control Normal group (Ex-C), (7)Immobilization group (I group), (8)Female Hormone group (H group) and (9)Calcium group. Parameters of biomechanics were measured and analyzed. Results:The result of biomechanic tests showed that:(1)No significant difference was observed in all parameters except Flexibility Coefficient between Normal Control group and all groups related to exercise, calcium and estrogen. (2)No significant difference was obtained between E-Ca group and Normal group in all parameters. (3)No significant difference was showh among all 4 groups related to Exercise in all parameters. (4)biomechanic test showed that Flexibility in H-group was worse th...更多an in Normal group, indicating that the biomechanic charaters in H group were not good as those in exercise groups. (5)There was significantly difference between I-group and all exercise groups in each parameter. Concludsion:Exercise was showed to be independent effects for improving biomechanic nature during the growing stage and early and middle stage after ovarietomy, providing valuable information for designing rational exercise scheme to prevent postmenopausal osteoporosis. 还原