I can run pretty indefinitely on soft trail, maybe its the technical terrain encouraging more knee bending too, but when I set off on the road I feel my form and knee drive diminish. I can stride out and the knee will rebound, but the pounding required to do this worsens the ACL tightnesss. I suspect this is due to a problem with calf activation, because when I run on the trail I feel much more energy traveling up the calf into the hamstring, slow calf activation apparently. Thing is Ive been skipping rope biking and running distance long enough (for years) that whatever calf problem I had, the atrophy is gone. So I am starting to think it might not be that anymore, but overdevelopment of the quad. I understand hypertrophy and activation while running are two different things, but my one footed jump, sprinting, etc is all fine the calf is firing until I run long.
So if I were to anser this myself, Id run primarily trail miles to solve this dillemma, but How have you found it possible to run longer road miles without runners knee acl problems etc?