The aim of the present study was to investigate the effect of eight weeks of intense endurance and intermittent training on bone density in old rats. For this purpose, 40 old rats (18 weeks old) were divided into four groups of 10 series including: control group, sham group, endurance training group and interval training group. In the following, the training groups did the desired exercises for eight weeks, five sessions a week. The exercises of the endurance groups were performed at a constant speed of 12 meters per minute and with an increase in the training time (28 minutes in the first week and 64 minutes in the eighth week). Also, the intense interval training group worked with constant time and increased training speed (the first week at 20 meters per minute and the eighth week at a speed of 40 meters per minute). Body composition and bone density in the whole body were evaluated through X-ray dual energy absorptiometer at the beginning and after the intervention. Data were analyzed using SPSS statistical software and one-way analysis of variance and Tukey's post hoc tests at a significance level of 0.05. The results showed that both endurance and intense interval training significantly increase the level of bone mineral density in the thighs of old rats (p<0.05). On the other hand, there was no significant difference between the two training methods on bone density (p>0.05). The findings of this research suggest that this type of exercise prevents the analytical effects of aging on bone density.
