This book establishes a comprehensive understanding of the role that shaft stiffness plays in executing a golf drive. A thorough set of experiments was conducted to answer explicit questions related to this goal. Specifically, how does shaft stiffness affect clubhead speed and how does it alter clubhead orientation at impact? What are the underlying mechanisms responsible for the pattern of shaft deflection occurring during the downswing? For the first time, a 3D, 6-segment forward dynamics model of a golfer and club was developed to answer these questions. The golfer model was optimized for...