The Edit Run Types window lets you define the types of runs you want to assign to runs. It's up to you to define any run type you want to track. For example, you could define: Trail run, Easy run, Intervals, Group run, Race, etc. The Run Types you add here show up for you to pick from in the Run Entry window. The abbreviation you give is displayed on the top-right side of each day in the Calendar window.

Simply click on the Edit button to edit a Run Type, or the New button to add a new Run Type. The Edit Run Type window (below) will come up to allow you to edit the Run Type information. The run you select as Default (see window below) will display at the top of the list above and also be selected by default when you enter a new run on the Run Entry window.