Is there a way to change a previously entered run activity to a walk activity (which I don't even see anywhere) so that I can have accurate year to date run mileage statistics? Or is there some other way to do it as opposed to deleting all my (dog) walks this year?
When you open the activity in Garmin Connect Web, in the upper left corner it says "Running". There is a small triangle next to that text. Click it, and you see your options for other activity types.
