I have a question for the "seasoned runners" (and anyone else who might know the answer). I started doing HIIT several weeks ago. I am running on a track to do it. A few days ago, I noticed that there was a different sound when my left foot hit than when my right foot hit. Paying closer attention, I noticed that the left foot was hitting a lot harder, then I noticed that while my right foot was hitting in a heel to toe manner, my left foot was hitting almost completely flat. I also do this when I walk, but it's not as noticeable because I don't make as much noise when I walk. Has anyone else experienced this? Do you have any suggestions to remedy this problem? Thanks in advance.