I am BT using maf formula, up to 50mpw. Hoping to raise that to 70mpw, then introduce some faster runs a couple of times a week. I do notice an improvement in 4 weeks (10:30min/mi down to 9:50min/mi), but part of that is recovery from FLM. It's frustrasting to run so much slower than usual I find. Also my legs always feel really heavy at this speed - but maybe I'm still recoveing. I bought a pair of flat trainers (boxing trainers actually) to try some short runs in, to see if I can manage more of a midfoot than heel strike. Anyone else do that?