Looking for some opinions here:
For a marathoner running in excess of 85 miles per week which of the the following three workouts are the most stressful on the body (require the most recovery time):
1) 10 min w-u, 20-30k @ 85-88% of Max HR (marathon pace), 20 min c-d
2) 30-40k @ 78-83% of Max HR (steady pace)
3) 40-50k @ 70-75% of Max HR (easy pace)
or are they fairly even
I think that #1 would be the toughest, due to the fact that it's a lot of work period.
#2 is probably the easiest, even though it's at a higher effort level. I think that the extra 10K of distance really makes #3 tougher, despite it being "easier".
It depends a bit on how fast marathon pace is (because a four-hour marathoner will be on their feet for a LONG time compared to a 2:20 marathoner for a 40-50k run). I think the very long runs will beat up the legs most (DOMS and so on).
The first option may cause less overt pain and soreness, but it will cause some serious fatigue that takes time to recover from. I know I always felt more or less okay after doing that sort of run, but would then crash five or six days later if I hadn't been really careful to take a couple of easy days after the long run.
On another note, a 50k run would be pushing it for a 85mpw runner. A typical rule of thumb is that your long run should be 20-25 percent of your weekly total.
My guess would be number 3 if you are not acclimated to running over 20 miles at a time otherwise I would say 1, if you were leaning toward 30K. Big difference between MP pace for 12.4 as opposed to 18.6.
#3 is definitely the least stressful.
I would think #1 and #2 might be fairly close because you are giving ranges for each. If #1 were 20k at 85%, that is noticeably less demanding than 30k at 88%. (Sorry for stating the obvious). Anyway, I think #1 or #2 would require similar recovery time, while #3 would certainly require less.