Originally Posted by
knotty
I had long past the point where breathing did any good and the legs started to slow down on their own no matter how much harder I tried.
It sounds like your legs could have given out before reaching your MHR. Kinda like the feeling one gets on hills. You can breathe but your legs just won't do it. More like lifting weights than anything. If your legs could, you would be pushing your HR way over the top.