Background :The purpose of this study was to evaluate the effect of eight weeks continues training on the expression of miR29mRNA in the cardiac muscle of healthy male rats. Methods: Male Wistar rats (n=6/group) were randomly divided into two groups: sedentary and training group. Training was prescribed 70-75% vo2max for 30 min, 5days/week. Hearts were isolated 24 hours after the last session. Using quantitave RT-PCR, miR29 expression changes were analyzed then calculated by 2ΔΔСТ method. To determine the significance of variables between study groups, independent t-test was used. Results: Results showed that there is a significant increase, in gene expression miR29a,c in training group compared to control group (P=0.001).But miR29b gene expression were significantly reduced (P=0.416). Conclusion: Based on the study findings, continuous endurance training induce physiological hypertrophy training is at the heart of the group and lead to a significant increase in expression levels miR29a,c. Since this increase leading to a significant reduction in expression of collagen isoforms, it can be concluded that rising miR29a,c in physiological hypertrophy induced by endurance training is directly regulates extracellular matrix and ventricular compliance.