Background and Aim: Leg stiffness has recognized as a parameter related to sports performance and injury risk. The aim of the present study was to compare of leg stiffness during hopping test between female and male athletes.

Materials and Methods: Thirteen females and 12 males of the best Iranian racket-players participated in this study and<span style="font-family:;" dir="RTL" new="" b="" fa;="" mitra";="" roman";="" "times="" roman";"="" 12pt;=""> performed the bilateral hopping test at a frequency of 2.2 Hz. The subjects' leg stiffness was measured and was normalized through dividing by their body weights. Independent samples t-test was used to compare the mean of research variables between the female and male groups.

Results: Leg stiffness in the females was significantly lower than the males (p< 0.001), however the body mass-normalized leg stiffness was not significantly different between two groups (p = 0.290).

Conclusion: The lower leg stiffness observed in the female athletes may be a factor justifying their weakness in speed-based performances during horizontal movements. Furthermore, non-significant difference in normalized leg stiffness between two groups may indicate using a risky strategy by the females in vertical movement to compensate for the less inherent stiffness of their tendinous and muscular structures. Choosing the proper training programs to change the leg stiffness, may be an effective method to enhance the performance and to decrease the injury risk.

Keywords: Leg stiffness, Female and male athletes, Sports performance, Injury risk