What Counts as a Long Run?

Yesterday when I was volunteering at the Buffalo Trace race, someone asked me how far I was running after the race was over. I said "About 15 miles." "That's a good long run," was the reply. "It's more like a medium run. Long starts at 18 or so" was my clarification.

Is that true? Long runs start at 18 miles? When I was actually running my 15 miles (which ended up as only 14 miles), I kept thinking about what mileage counts as short, medium, and long. And I decided it isn't mileage, but rather time. Total time running is more important than distance covered. Distance is too dependent on terrain and weather. Hot vs cool weather, trails vs roads, hills vs flats...they all change the distance we can cover in the same amount of time. But "time on feet" can be consistently used as a metric for effort.

For me, using time as the measuring stick, my short, medium, and long runs fall into three easy brackets. Any run under an hour is a short run. One hour to 2 hours is a medium run, and runs over 2 hours count as long runs. Based on my easy conversational pace (and moderate weather), a short run is basically under 7 miles, medium is 7-12 miles, and long is 13+ miles. Yesterday, my run was 2 hours and 5 minutes long (and just shy of 14 miles on the trails). It was a long run.

For my marathon training, leading up my July 31 goal race, I plan on 3 short runs each week, plus two medium runs and one long run. One day of rest. Only 70 days to the race!