Ty:
Great question! On the days you are feeling really good, push the HR and speed up into the upper Z2 range. Those days may take a bit longer to recover from due to that mechanical load you are referring to, so don’t push this effort if you are tired. On most days, stay in the lower half of Z2. On those days when you can tell you’re tired, drop down into Z1 or shift to a non weight bearing modality like cycling.
I hope that helps.
Scott