How do I set a personal goal for a total running distance in a specific period of time? Eg 50km in 2 week time frame
he time limit for an ordinary challenge is one month.
As @e7andy wrote, you can use Challenges, if Goals do not fit your needs. At Challenges, the dates are actually rather free. By default you can create a Day Challenge, a Weekend Challenge, a Month Challenge, or a Year Challenge, but you can also create a Challenge with custom start and end dates, so the 14 day challenge would not be a problem.