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Introduction & Objective: Theoretically, it seems that calcitonin can accelerate the healing process, mainly by decreasing bone resorption, but in the literature, there are lots of controversies. The aim of this study is to evaluate the efficacy of calcitonin on bone healing. Materials & Methods: This experimental double blind study was performed on laboratory animals in 1383 at Shiraz University of medical sciences, Department of orthopaedic surgery. Thirty guinea pigs were divided into three groups of ten. Then, they were operated and drilled in proximal part of both tibias. In group A, after operation, calcitonin (30 IU/kg) was injected intraperitonealy (IP) for 7 days. In group B, the injections were subcutaneous for the same time and dose. Group C was selected as control group. Half of the guinea pigs in each group were sacrificed after 2 weeks (A2, B2, C2) and the others after 4 weeks (A4, B4, C4). Multiple sagittal sections were performed on the tibia. In all groups, the formation of periosteum, cortical and trabecular bones were measured. Collected data were analyzed using Kruskall- Wallis test. Results: In A2 and B2 group, the difference of periosteal formation was significant as compared with the control group (p= 0.009). The difference of periosteal formation was even more significant in A2 (IP injection) than in B2 (subcutaneous injection) group. The difference of cortical and trabecular bone formation in groups A2 B2 were not significant in comparison with the control group during the second and fourth weeks. Conclusion: High dose of systemic calcitonin is effective for the rapid formation of periosteum in the early stage of bone healing.

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Background & aim:  Decreased bone density, especially in women, is a health risk factor; therefore, the aim of the present study was to investigate the effect of a resistance training course with vitamin D supplementation on bone absorption markers in girls.
 
Methods: The participants of the present semi experimental study were 24 non-athlete girls in Boroujerd (mean age 21.6 ± 2.04 years, mean height 155 ± 5.5 cm and average weight 64.13 64 4.9 kg) who participated voluntarily and were randomly divided into four groups of six (resistance training, vitamin D intake, resistance training with vitamin D intake and control group). Resistance training consisting of eight weeks (three one-hour sessions per week) was performed in accordance with the principle of overload. The participants were given Vitamin D supplementation for eight weeks (once a week) using vitamin D tablets (8 pearl IU50000) with 300 ml of water. Blood samples were taken 48 hours before the beginning of the protocol and 48 hours after the end of the last session to measure the serum concentrations of parathyroid hormone and calcitonin. ANCOVA and Bonferroni post hoc test were used to analyze the hypotheses.
 
Results: The results indicated that after eight weeks of resistance training, as well as eight weeks of resistance training with vitamin D, a significant increase in serum calcitonin concentration (p=0.001) and a decrease in serum parathyroid hormone concentration (p=0.001) Occurred.
 
Conclusion: It seems that resistance activity and vitamin D consumption increases calcitonin and decreases Parathormone in sedentary girls, which probably has a positive effect on bone mass.