Heel strike running my 1.65 miles to and from work would result in the bottom of my foot having a spasm like muscle or tendon that would produce a stabbing pain. My ankle feeling the old car crash injury. Also, my knees would have an ache and not want to do much. This would mean running a couple of days, then walking the rest. Or depending upon how badly I was hurting, take the truck.
Today was my fifth day running out of six days. Which is fairly unprecedented. The hill still requires a bit of will power to keep running up and over. But, that is minor.
Ankle feels fine. Bottom of the foot does not hurt, although walking fast can still flare it up. Knees do not hurt, unless I do not do the stride correctly. The only way I can describe the needed motion is a slight kick. Which is a further extension of the leg prior to your foot landing. If I shorten that kick I start to feel a twinge in my knee. Adjusting the stride eliminates that twinge.
It is very interesting.
Never having been much of a runner there are certain notions I had that were left unchallenged until recently. One of the bigger ones was the thought of recovering while still running. That is to say, if you do a sprint, at the end of the sprint, you stop and breath hard until you have re-gained your "breath". Now I realize you can do the same thing and keep running.
The second was that a marathon consists of some small stopping here and there instead of a continuous run for the full 26 miles.
In retrospect it is a 'Duh!' in my mind.