"At first when I was looking for something challenging, my friends and I took to the parks where skateboarders and mountain bikers were doing tricks. There weren't any mountains in the Ruhr region where I grew up," he said.
"The skateboarders did look sideways at us, but then we were pretty good at tricks and could do some things they couldn't so they were soon impressed. We even converted a few mountain bikers."
Eichholz started riding on one wheel when he was about nine years old - thanks to the clubs in his hometown of Bottrop. Soon he was performing tricks and has travelled the world showing off his skills and taking part in - and winning world competitions.
It was during a trip to China, he said, that he met Kris Holm, the ultimate extreme unicyclist.
"That started me on the extreme unicycling route. It was totally cool. I was in New Zealand and went to the mountains and realised it would be possible, but that it would be difficult. Then in 2010 three friends and I went up the Zugspitze mountain and came down on unicycles."
Last summer he took a trip to the Italian Dolomite mountains along with a friend Stephanie Dietze and a cameraman to make a video and take pictures in cooperation with his main sponsor, Adidas sportswear.
"It is difficult to decide where the line is between amateur and professional," he said. But he added he was able to live from his sponsorship deals and the proceeds of his appearances.
However, at the grand old age of 26, he is also making plans for his retirement, working through the winter to finish his degree in urban planning.