I've just been out and completed my W4 R1 run and I'm just amazed at this programme. Each time there is a step up, I'm convinced it's going to be "one step beyond" my ability but again I managed it. Not quick and not pretty and my mantra for the last running section went something like "ouch, no I can't..... ouch, gonna... stop... soon" but I made it. Still loving reading everyone's posts; I run alone so it feels like my own running club.
This is also the first run where I didn't feel like my calves were going to stop me before my lungs. I've been running in Nike Frees and I believe they can be a bit harder on unfit calves.