The knuckleball is one of the most interesting phenomena in all of sports. In baseball, Tim Wakefield, RA Dickey and countless other pitchers made a name for themselves just because they could throw the ball with almost zero spin. In soccer, Portugal’s Cristiano Ronaldo and Turkey’s Hakan Calhanoglu have both left opposing goalkeepers stunned and beaten by their knuckleballs. Although there is virtually no spin on the balls thrown and hit by these four athletes, there is a huge amount of movement on each ball. Why does the ball move so much when so little spin is put on it?
Jeremy Lynch and Billy Wingrove, known on YouTube as the “F2 Freestylers”, are an extremely popular duo of talented soccer tricksters who have made a name for themselves online. In this video, they explain how they’ve perfected their ability to hit a perfect knuckleball (and show off their skills a little in the process). According to phys.org, the swerve that makes a knuckleball almost impossible for a goalkeeper to save is caused by the air around the ball. Since a ball is a smooth sphere, the forces caused by aerodynamic lift fluctuate as the ball travels towards the goal in its straight path. These fluctuations cause the ball to move in such a seemingly unnatural way.
The knuckleball, however, is not exclusive to just a soccer ball or a baseball. A study by students at École Polytechnique’s Hydrodynamics Laboratory in France found that almost any ball, be it a tiny plastic bead or a 7 kg steel ball, will move similarly to a knuckleball seen in sports if dropped into a tank of water.
To this day, the knuckleball leaves opposing batters and goalkeepers bamboozled and frozen by the unpredictable, erratic ways that the ball moves towards them. Though extremely difficult to master, many goal-scorers and pitchers will continue to use the knuckleball to their advantage in the coming years.