Quote Originally Posted by Susan Otcenas View Post
Today I did my longest run since injuring my IT band: 8.3 miles. I am in the aerobic base building phase right now (Hadd's Phase 1), so these are slooooow miles at very low heartrates. Today I averaged 11:28 per mile at 139bpm. It's surprisingly hard to run this easy, but that's the whole point.
That was last week. This week's long run was on an almost identical course, but I did 8.4 miles at 11:09 per mile at an avg HR of 137. This is good. Lower heartrate, faster miles! I can't really explain the difference, other than that I may have had more sleep this week than last week. Last Thursday was a rest day and this thursday was a swim, so my legs were equally rested in preparation for both runs (I have very little kick in my swim style.)

It's interesting to me how some days feel so great, and other days like running through molasses. Sleep, hydration, nutrition, weather, apparel choice... there's so many variables!