To clarify the relationships among ball speed, muscle mass, and muscle strength when kicking soccer balls. [Participants and Methods] Ball speed, muscle mass (body composition components), and muscle strength (maximal isokinetic leg flexor/extensor strength) were measured in 26 male university students playing football or futsal on a regular basis when they kicked soccer balls with their dominant and non-dominant legs, and the relationships among these items were analyzed. [Results] Ball speed was correlated with muscle mass for the dominant leg, and with maximal isokinetic leg extensor strength for the non-dominant leg. [Conclusion] The relationships among ball speed, muscle mass, and muscle strength may vary between the dominant and non-dominant legs.