Background and aim: With respect to attachment and mechanical relationship of hamstring and calf muscles, interaction between their function is unavoidable. Inspite of prevalence of hamstring and calf muscles shortness, there is not any statistical data about the relationship of shortness of above-mentioned muscles in Iran. The aim of this study was to verify of this prevalence.

Materials and methods: In this study 3308 healthy girls with age 3-17 years old participated. Length of calf muscles with dorsi flexion angle and hamstring with hip flexion angle (SLR) in both side were measured.

Results: The prevalence of hamstring and calf muscles shortness with together was20% in right and 25% in left side .The Prevalence of hamstring and calf muscles shortness with together in 20 district was greater than 3.The greatest amount was seen in secondary school(31.6%).               

Conclusion:The results indicated that most of subjects who had hamstring shortness, they had also calf muscles shortness, so if there is any shortness in one of them, we shouhd pay attention to shortness of the another.