Hermens was one of the best Dutch long distance runners in the 1970s, winning national titles in the 5 km, 10 km and cross country. He broke the World Record for one hour twice (1975 and 1976), the latter performance remaining unbeaten until 1991. The first record earned him the title of Dutch Sports Personality of the Year 1975. Hermens was on the Dutch Olympic team for 1972, but was one of the few members to withdraw following the Israeli hostage drama. He returned to the Olympics in 1976, competing in the 10 km and marathon. In 1985, he created Global Sports Communication, which became one of the largest sports management companies involved in long distance running. Among his clients are many Olympic and World Champions, most famously Haile Gebrselassie.
Personal Bests: 10000 – 27:41.25 (1977); Mar – 2-19:49 (1976).