Good question. I think it depends on the size of the loop, but were do you draw the line
It's called a lollipop, apparently.
Thats a good name for it!
Thing is, I'm morally against doing out-and-back runs - so where do you draw the line is an important question for me ;) Agree with Jimbo, it's down to tail vs loop ratio. (stick:lolly ratio)
Lollipops come in all shapes and sizes. Are you running at the cornershop or the county fair? If you're training for 30k plus it'll probably be a toffee apple. Anyways, that's what i'd heard it's called. I try and avoid them. They tend to go straight to my hips.