The Effect of a Period of Aerobic Training on the Levels of Bone Metabolism Biochemical Markers in Girls Aged between 11 and 12

Nowadays, osteoporosis is one of the risk factors for public health. Studies conducted on the role of physical activities in bone density have revealed that physical activities have important effects on the development and maintenance of bone mass. But there is doubt about the type and intensity of exercise which induces maximum anabolic effect on bone. This study aimed to study the effect of six weeks of aerobic training on bone growth markers (serum levels of alkaline phosphate, calcium and phosphorus) in 11-12-year-old girls. In this study, 20 girls (11-12 years old) were randomly assigned two groups: experimental (n=10, mean age 11.3±0.48 years, weight 41.80±7 kg, height 144±0.06 cm) and control (n=10, mean age 11.4±0.51 years, weight 43.70±4.7 kg, height 147±0.05 cm). The experimental group participated in an aerobic training program for six weeks (three sessions per week, each session 45-60 min. with 70-75% HRR) while the control group had no training. Before and after the training protocol (after 12 hours of fasting), 5cc blood was takenfrom subject's antecubital vein in order to estimate bone markers. Findings were investigated using descriptive and inferential statistics (dependent t test to compare pretest and posttest in each group and independent t test to study the differences between the two groups at p<0.05 using spss software version 19). The results indicated that six weeks of aerobic training significantly increased the serum concentration of alkaline phosphate (P=0.00) in the experimental group. But the serum levels of calcium and phosphorus did not significantly change in this group. In the control group, serum level of alkaline phosphate increased, but this increase was not significant. As a result, it can be said that aerobic activities at growth age may be effective factors to increase bone density in adolescents.