Fitness PRO Art Claas van der Heide has a broad range of interests: the athlete and CrossFitter loves movement in any shape or form. He is particularly fond of CrossFit, yoga, surfing and basketball. His motto is "If you fight, you can lose, but if you don't fight, you've already lost". When it comes to sports products he looks for a balance between quality, design and functionality so he can enjoy himself while exercising. The fitness fan has developed a lot of qualities through sports, three of which being team work, discipline and mental strength. This knowledge is something he wants to pass on to others, as well as his enthusiasm for the quality of his movements. In his blog, Heartcore Athletics, he shares his experience and knowledge regarding fitness, CrossFit and medicine ball training.


Similarly, Sarah Kraatz also supports Keller Sports with words and deeds as a Fitness PRO. Whether she is training the Keller Sports PROs at her gym or testing new products, personal trainer Sarah is always ready to contribute with her specialist know-how. Like Isabell, through practising sports she has learnt to push forward even when you have reached your limits, as you are always able to grow from it. For her, functionality but also looks are the most important aspects of sports products. In her Munich gym Sarah offers modern types of training like EMS-Training, Barre Concept© or cardiovascular endurance training, as well as classic fitness concepts like yoga, Pilates, running, spinning and back training.