Winter is still here in Pittsburgh.  Yesterday I was able to ride my bike outside, but a big snow storm passed through overnight. Running outside was not an option this morning, so I ran on the treadmill.

My run workout included hills sprints.  I have never done hill sprints on a treadmill before, so I was in for a bit of a surprise. The run workout was quite simple.  Easy run for 40 minutes, followed by 6 x 30 second sprints uphill, with easy recovery in between.  It was the exact same workout that I did last Friday.

To do the ‘hill sprints’ on the treadmill, I increased the grade to 5%, and then increased the pace to match my sprint pace.  I did the first two sprints, and discovered that doing them on the treadmill, was nowhere near as demanding as doing them outside.  For the remaining sprints, I went steeper and faster.  They still didn’t feel as demanding.

The sprints were still hard work, but I didn’t get as out of breath, and my heart rate didn’t get as high, as it did last week.  I am sure I still had a good workout, but it just didn’t feel the same.

My guess is that difference is caused by gravity.  Outside, I was physically carrying my body up a hill against gravity.  On the treadmill, my body was going up a “hill”, but I was really just running up a sloped surface.  That is the only explanation that I can think of, as to why the intervals didn’t feel the same on the treadmill.

Luckily, I think we have seen the last of the big snow for the weekend.  I should be able to do my long run outside tomorrow.  The path at the local park has been plowed, so all I will have to deal with, is the cold.