The purpose of this research was to identify specific biomechanical positions in the throwing motion that are associated with different levels of rotational torque at the shoulder and valgus stress at the elbow. They studied the throwing motions of 169 pitchers between the ages of 9 and 18. Motion capture and video analysis were used to determine whether the pitchers met 5 specific parameters considered to represent good pitching mechanics. They found that, especially in the younger throwers (9-13), the humeral internal rotation torque and the elbow valgus torque were reduced if pitchers met 3 or more of the 5 criteria.