Although the length of kick may end up being a little shorter, the changes make the Telstar 18 more balanced, says Alam. On other balls, Alam and his team have found that there is a difference in how the ball flies based on where it’s kicked in relation to the seams. His tests have found that the Telstar 18 ball doesn’t have as much variation. The total length of seam of the Telstar 18 is 14.1 feet, 3.28 feet more than on the Brazuca. With the longer seam, and more symmetric panels, no matter how the ball is turned there is the same amount of seam exposed. “The other two balls were not like that, they were significantly different,” he says.
On the other hand, replicas (sometimes called training balls or gliders) are designed to be just like the official match balls but are much cheaper. Their panels are often stitched rather than thermally-bonded and are made of a different material. However, they’re not necessarily less durable than official match balls. So, they’re the recommended option for most players. https://www.youtube.com/watch?v=j2Xn84L3Kcs