Quest! It's a quest! A quest is just "A search or pursuit in order to find something; the action of searching" (OED). What is the something here? If you run 100 miles instead of 10 miles, have you found anything?
"Quest" is also a grand word because in chivalric or Arthurian romance it is "an expedition or search undertaken by a knight or group of knights to obtain some thing or achieve some exploit."
▸ a1470 T. Malory Morte Darthur (Winch. Coll.) 966 They supposed that he was one of the knyghtes of the Rounde Table that was in the queste of the Sankegreall.Is the logging of 100 miles a hundred times within a 100-day time frame anything like the Holy Grail?