Biceps Activity During Windmill Softball Pitching: Injury Implications and Comparison With Overhand Throwing

Fast-pitch softball is one of the most popular female athlete team sports in America. The Amateur Softball Association, the national governing body that selects athletes for the US Olympic team, reports that 1.3 million fast-pitch players were registered with them in 2008, and it has been estimated that the total number of female adolescents competing in fast-pitch softball in 2008 was upwards of 2.5 million. In spite of fast-pitch softball’s immense popularity at the high school and collegiate levels, there remains a scarcity of sports medicine research on the game’s most notable activity: the windmill pitch. The conventional belief in softball has been that the underhand throwing motion places little stress on the arm and pitching-related injuries among windmill throwers are rare. Unlike baseball’s governing bodies, the Amateur Softball Association has no rules limiting the number of innings pitched at any level of play.

Windmill pitching produces high forces and torques at the shoulder and elbow, making the biceps labrum complex susceptible to overuse injury. Little is known about the muscle firing patterns during a windmill pitch. This study by Dr. Verma and his team hypothesized biceps muscle activity is greater during a windmill pitch than during an overhand throw.