A knuckleball in football is a shooting technique where the ball does not spin as it flies through the air, causing it to move unpredictably and making it difficult for goalkeepers to predict its trajectory. The technique involves hitting the ball firmly near the center and resisting following through, which creates a flat trajectory and minimal spin. The knuckleball is considered the most difficult and advanced shooting technique in football. It requires a lot of practice and mental preparation to master. The sweet spot area for hitting a knuckleball is right around the area between the toes and the laces. While the knuckleball cannot be directly observed with the naked eye, it can be investigated using a smart ball and training machine.