I gave my heels and calves some tough love last night with a foam roller - and could certainly tell the difference afterwards. No running until I can go a couple of days with no heel-cord tightness. All I need is to put an already tight tendon under too heavy a load trying to trail run... The solution seems pretty obvious given the aftermath of my treatment last night! Tight calves (and shins) are also part of this, of course. Hamstrings and quads are fine and indeed my hammies are super-flexible