As has been the case every four years since 1970, Adidas unveiled the official ball of the 2026 World Cup in October last year. The Trionda attracted attention for its appearance with a tricolor scheme representing the United States, Mexico, and Canada, the host countries for this year’s cup, but it also raised doubts due to its unprecedented structure of four panels thermally bonded together with heat and adhesives, a configuration that made some question the stability of the ball on the field.
John Eric Goff, visiting professor of physics at the University of Puget Sound and coauthor of a study on the ball's performance, explained in an article published in The Conversation that “fewer panels could indicate a shorter overall seam length and, therefore, a smoother surface. And smoothness is important because the thin boundary layer of air that adheres to the surface determines where the flow separates, how large a wake is formed, and how much drag the surface experiences.”
The “Jabulani,” the ball used in the 2010 World Cup in South Africa, had a similar characteristic that during matches caused unexpected changes in the direction of the ball or sudden reductions in speed during flight. In an attempt to counter that, Adidas incorporated deep stitching, three pronounced grooves in each panel, and a textured surface designed to improve aerodynamic stability into the Trionda.
Goff and his colleagues sought to determine whether these modifications were sufficient to avoid the irregularities observed with the Jabulani. To do so, they subjected the Triwave to a series of wind tunnel tests, a technique used to analyze the interaction of air with moving objects under various conditions. The tests made it possible to measure the ball's aerodynamic force coefficients, for example, the parameters that describe how the air generates drag and modifies flight stability.
In addition, the researchers analyzed the so-called “aerodynamic drag crisis,” a phenomenon that occurs when the air resistance changes abruptly when certain speeds are reached. The results obtained with the Trionda were compared with identical simulations performed on previous World Cup balls: Al Rihla (2022), Telstar 18 (2018), Brazuca (2014), and Jabulani (2010).
The experiments showed that the Trionda reaches its critical point of aerodynamic drag at a speed close to 43 kilometers per hour (km/h). This figure is below the 50 to 65 km/h range recorded by Adidas’ Al Rihla, Telstar 18, and Brazuca, as well as the 79 to 97 km/h reached by the Jabulani.
Courtesy of AdidasThis means that the official 2026 World Cup ball, thanks to its rough surface and in comparison to the Jabulani, slows down the airflow more evenly in short-distance plays, such as corner kicks or free kicks. Consequently, the ball should be more stable in these types of actions and would exhibit less unpredictable movements.
However, at higher speeds, the ball in the next World Cup would lose range. This implies that, for example, in a goal kick that seeks to reach midfield, the ball could descend a few meters earlier than expected.
“In our simulations, the difference with Brazuca, Telstar 18, and Al Rihla is not huge. But big enough for players to notice that long shots stay a few meters off target,” Goff says.
The authors also suggest that the way in which the connected-ball technology is integrated could influence the aerodynamics of the new ball. Since 2022, balls used in World Cups have incorporated a chip that sends real-time information to the video refereeing system (VAR) and the semiautomatic offside system.
In previous models, this measurement unit was suspended in the center of the ball. With the Trionda, the architecture changed: The sensor is now located in an inner layer inside one of the panels, while counterweights were placed in the other three to balance the structure.
The researchers clarify that their study cannot predict exactly how the ball will behave during each match of the next World Cup. They point out that the tests were carried out with shots without spin, and that variables such as altitude, humidity, temperature and atmospheric pressure also influence the trajectory after each hit.
Despite this, they believe their findings help explain some of the physics behind a spectacular goal or an apparent mistake by a striker. “Every four years, a new design offers a new way to look at how physics comes into play, not in theory, but in the movement of an object that every player on the soccer field must rely on,” Goff says.
This story originally appeared on WIRED en Español and has been translated from Spanish.
