Bas Groothedde, husband, father of two, entrepreneur, scientist, teacher, writer. But above all enthusiastic and curious triathlete. Graduated and obtained a PhD from TU Delft and the Executive program MIT Sloan School of Management in Boston. His business in supply chain management and data analytics that he started in 2008 has taken him all over the world. And yet, at the age of 50, Bas decided to change course and pursue two of his dreams. The first long-held dream was to race in Hawaii at the Ironman World Championship, Kona. Bas put everything aside for a year, training hard, to qualify for Kona and do the research needed for this book. Successfully. With his finish at Kona, in the company of his wife and children, this dream came true. It marked the start of another adventure. His desire to devote himself entirely to the sport. He started a new company: Apex Triathlon. With the aim of helping to make the sport accessible. That meant he went back to college. This time kinetics and physiology and he has completed a coaching program in the US. The studies, experiments, literature combined with the experiences and lessons of the past seven years of trial and error form the basis of this handbook.