is sixteen miles (not a long run) at once better than 17 mile day split between two runs. is 80-90mpw on singles better for you than 85-95 mpw on singles.
i basically need someone to explain the difference between training on singles and training on doubles
Check out Pete Pfitzinger's website. He has an article about doubles.
If you're going to ask dumb questions like is 16 singles better then 17 doubles this thread is stupid.
BUT yes 16 single is better then 17 double. Now 16 single is not better then 20 double. And 80-90mpw in single is probably closer to being equal to 90-100 in doubles.
SIMPLE FACTS: doubles gives your body more recovery allowing you to put more quality in, as in two ten mile runs at 6 minute pace. Doing 20 miles at 6 minute pace is a greater accomplishment but its also a greater stress on the body and not everyone can handle that. I think if you're doing anything over 90mpw doubles is more beneficial. It lets you get i better quality without sacrificing quantity.