The official ball for the 2018 FIFA World Cup in Russia has received Empa's "stamp of approval" after numerous rigorous tests. Some goalkeepers had been critical of its flight characteristics, but the reason for this may lie somewhere else – the rather unconventional appearance of the new ball.
Football lives on emotions. When it comes to this year's FIFA World Cup ball, however, Empa's experts are completely unemotional. When asked about their impression of the flight characteristics of the Adidas model "Telstar 18", which had already been criticized after initial test matches: "Impressions are subjective", says Martin Camenzind of the Laboratory for Biomimetic Membranes and Textiles. "We rely on objective parameters to characterize the Telstar 18." Remarks by Spain’s goalkeepers David De Gea and Pepe Reina or the German goalie Mark-Andre ter Stegen that the ball is "fluttering" is, therefore, hardly impressive for Camenzind. In any case, the Telstar 18 has successfully passed the test series that was specially developed by Empa experts in St. Gallen for official tournament footballs – and that's all that matters to the Empa researcher.
On behalf of FIFA, Empa has been conducting the incorruptible series of tests on footballs striving for the FIFA quality program's seal of approval for 22 years. Not every ball passes the test. It is not only the circumference and weight of the ball that are measured precisely. In addition, despite being crushed 250 times in a water tank, it may only absorb a minimal amount of liquid, must be able to hold its air and always jump off at the same height when it impacts from a height of two meters. To prove that it is a perfect sphere, the ball is also measured at no less than 4’000 points. And finally, the ball must retain its shape even if shot against a steel wall 2’000 times at 50 kilometers per hour.
Such standards also determine the quality and consistency of the sport. When the test series were introduced, not all manufacturers succeeded in achieving the required properties: "Time and again, specimens failed", recalls Camenzind. Some leather balls had increased in size considerably after the procedure or absorbed too much water. Today's balls are glued or welded, because traditional seams could give way over time. Likewise, most of the traditional leather has given way to plastics, the surface of which is specifically textured, which should enable the ball to be guided more easily, especially when the field is wet.