Dr. med. Michael Fritz is general practitioner and sports medicine specialist from Viersen, NRW, Germany.  2. chairman of the Sportärztebund Nordrhein, member of the scientific advisory board of the academy for “Weiter- und Fortbildung in der Sportmedizin” and editorial member of the journal Sportmedizin in Nordrhein. For the Sportärztebund Nordrhein he has worked as a course instructor and lecturer in further training. In media-supported amateur sports projects, he led over 1000 runners to complete the marathon and 1600 non-athletes to complete the 10 KM run. As an experienced endurance athlete he has finished more than 50 marathons, over 20 ultramarathons and 18 Ironman triathlons.