Advent calendar day 24

Here is the last question in the Christmas calendar for 2018. Remember, the first letter of the 24 answers will make a new question. To complete the calendar, send me a message with the answer of this new question. I will publish the correct answers the evening at 25th December, so that is the time limit! Ok, here we go! When Colbin Kolbe won the JWOC sprint this summer, he became the second German to win gold at the junior world orienteering championships. Today I want the last name of another German, this one with an international senior medal. This person has won a bunch of German championships, and is still sharp when being the reigning German champion at the middle distance. Number two in this race was actually half the age of this runner.