Physical education in younger school age is very important. But in practice, this subject is not carried out regularly or is not performed by pedagogues of physical culture. Problem of the research was to determine whether the developmental gymnastics program had an effect on development of explosive strength with younger school age girls. The sample of respondents for experimental group consisted of 59 girls and for control group 45 girls aged 9 to 11 years. To determine the level of explosive strength three tests were used. Data processing was performed by the statistical program SPSS v. 20. For all data, the parameters of descriptive statistics were calculated. To determine the differences between the groups, a t-test for independent samples was used with calculation of significance of the size of difference (Cohen's d). The research has shown the effects of the developmental gymnastics program on the development of explosive strength with girls aged 9 to 11 years. Differences in explosive strength were identified in favor of the experimental group in two out of the three variables. The results obtained accurately indicate that respondents included in the development gymnastics program have a significantly higher level of explosive strength than respondents who only attended physical education class.