The Science Behind a Knuckleball

The knuckleball is one of the most interesting phenomena in all of sports. In baseball, Tim WakefieldRA 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, 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.

4 thoughts on “The Science Behind a Knuckleball

  1. Jacob Gross

    The knuckleball is such a valuable pitch in baseball. It takes a lot of time to perfect a knuckleball as well as a tremendous amount of hard work and effort. It can resurrect player’s careers such as R.A. Dickey’s. An interesting point you made is how the knuckleball is not only in baseball and soccer but also almost any ball can knuckle. I play goalie in soccer and have experienced so many times a ball that knuckles, which obviously is so hard to save. Knuckleballs are my worst nightmare, but observing them move are fascinating.

  2. Matthew O'Brien

    I thought that this was a very interesting idea for a blog post. Being a New York Met’s fan, I watched happily as RA Dickey confused the best hitters in the world. I also watched as he struggled at times to perfect the very difficult technique required to throw the pitch.

    I did further research into the knuckleball, and found that normal fastballs rely on a gyroscopic effect from spin that gives them a straight trajectory. Just as reducing spin is beneficial in baseball, there are many sports situations where increasing spin can be very helpful. This would be a cool topic to further explore. This article describes how to take advantage of backspin to help in short range golf strokes.

  3. Jarrod T Skole

    I am a soccer player and the knuckle ball is about the only shot I can do without trying very hard. I never knew how exactly how it happened but after watching that video clip you put in, I understand exactly how it works. The only thing I am still curious about is about the follow through after the shot. One of my friends is a kicker at Temple and he says to get the perfect knuckle ball you do not follow through on it. I believe as long as you hit the ball in the middle and do not lean back when kicking you will knuckle it. Do you have any input on whether you need to follow through for the perfect knuckle ball?

    1. Anthony Michael Calligaro

      I play soccer and baseball and find the knuckleball to be the most interesting aspect of both sports. In soccer, I play defense because I’m terrible at shooting, so I would have no chance at kicking a knuckleball. For baseball, I played centerfield, but had the worst arm on the team. So clearly, I never considered pitching, let alone pitching a knuckleball. However, someone on my team, who was struggling as a pitcher, developed a knuckleball and actually used it in games to be somewhat successful. Below is a link to one of the videos he used to learn how to perfect the knuckleball.

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