I have read about the training of some top athletes and I saw that one of them had put all the hard training on only 3 of the days in 1 week.
This would seem more logical than spreading it out in the week. Bacause with this approach the hard days will be tiresome but u are sure to recover on the other days.
It was something like this:
m: m:easy 10km evening easy 10km
t: m: 6×5 min AT e:6x1000m
w: m:easy 10km evening easy 10km
t: m:5x300m, 5×200, 5×150 e: 10x80m hill sprint
f: m:easy 10km evening easy 10km
s: m: 6×5 min AT e:6x1000m
s: m:easy 10km evening easy 10km
Think it would be a good idea? instaed of having 4 hard days pr week, or use 10-14 day cycle to get in the quality work