I'd imagine a split helps in terms of volume of quality miles as you run a high number of miles slightly more rested but if you're training for an endurance event you're not acclimatising your body to the continuous activity you'll be putting it through.
that said my short-long runs could be seen as a more extreme version of the split long runs as you recover overnight covering a high volume of mileage spread across a number of days rather than put your body through it at once with a continuous effort.
I'd say ultimately it probably doesn't make a huge world of difference.
I'd imagine a split helps in terms of volume of quality miles as you run a high number of miles slightly more rested but if you're training for an endurance event you're not acclimatising your body to the continuous activity you'll be putting it through.
that said my short-long runs could be seen as a more extreme version of the split long runs as you recover overnight covering a high volume of mileage spread across a number of days rather than put your body through it at once with a continuous effort.
I'd say ultimately it probably doesn't make a huge world of difference.