The idea is to stay below the Goal (white) line. That way I’m reaching my goal each week. This week I killed it and I still have two more outings planned. I’ve walked over 100 miles as of today in seven weeks.
I set up a calendar with small incremental goals each week, ending in a half marathon. I started this because I couldn’t think of a satisfactory reason to say no to the challenge. So, each week I do a little bit more than the last — focussing on endurance. So far so good.