It may sound simple - to hit as many strokes on a small ball as many times as possible in ten seconds.
For 13-year-old Erik Nyberg from Sundsvall, on the other hand, it is easier than for most.
Won 30,000 in a big competition
On New Year's Eve, he was awarded SEK 30,000 after winning a competition.
His result?
47 strokes in 10 seconds.
See Erik's incredible speed and hear him tell why he thinks the ball is so fun in the clip.