In a multibillion-dollar sport like basketball, one might expect trainers had figured out every nuance of aerodynamics, mechanics and all things Newtonian to increase the rate at which the ball goes through the hoop. Think again. Take free throws. For 50 years professional players in the United States have sunk these shots from the “charity line” – so called because the points are supposedly such sure things they’re gifts – at a rate of about 75 percent. That figure that seems to reflect a fundamental limit on human performance, like a three-minute mile. But mechanical engineer Larry Silverberg of North Carolina State University doubts it. He believes the reason free throw percentages are not higher is that no one had properly analyzed them to determine the optimal trajectory.