This might sound a bit demented, but bear with me. I started the following thread a few years ago:
and put the finishing times down to the father & son's innate talent, not the Crocs.
I absentmindedly Googled "are crocs good for running" earlier and there's a lot of (admittedly anecdotal) evidence that they're akin to wearing 'ultra lightweight trainers' or 'running barefoot on grass'. So I've taken the plunge and ordered a rather fetching white pair (all they had in a 12) from SportsDirect. I'll not be running outside in them - my neighbours think i'm a lunatic as it is - but will see how they perform on the treadmill.
It they're bobbins, it's only an £18 outlay, and they'll become my go to 'taking the bins out' footwear of choice.