anything wrong with all long runs?

[Jeff Linger]

Arthur Lydiard also supports the varied plan. 12-8-12-8-12-8 would be better than 6x10. USATF certification courses often use phrases such as "hit it and rest, hit it and rest". Pfitzinger, Daniels, etc, etc, etc, the message is the same as this. Hit it and rest, hit it and rest. You stress a system, you provide the system time to recover, and you re-introduce it to stress again.  The improvements do not occur during the stress, rather, during the recovery.

[Tom]

Having tried both methods I'll cast my vote for the varied plan as well. Varying mileage through the week rather than same every weekday just seems to keep things more interesting if nothing else, but it also sounds like there may be training benefits as well.

[Sasha Pachev]

My thoughts on variation is that what should vary the most is intensity. If you need to recover, ease off the pace. If you need a workout run a portion of your run quicker. The distance itself is an almost free aerobic stimulus, you should push to the max that you have the time for and ability to recover from daily. Since the pace wears out more than the distance, easing off on the pace can help you cover the same distance even if you need recovery.

[Jeff Linger]

I'm not sold on the simple decrease in pace as a indicator of rest. Decreasing pace but maintaining mileage yields a longer time spent on the road and a longer time the body is subject to a degree of stress, although a lighter load of it. I'm not sure really about the science behind it, but I know for certain that Lydiard promotes the idea that if you're going to run 10 miles/day average, you're better off running more than 10 one day and less than 10 the next. I think he indicates this in his book Running the Lydiard Way

[Sasha Pachev]

Time on feet is not very much of a factor. Extreme example - 3 hour walk vs 1 hour run at a brisk pace. Clearly 3 hour walk is not as strenuous except maybe on the back even though it is 3 times as long. Less extreme. If I do 9 miles in 57 minutes every day I'll be stale at the end of the week. If I do 13 in 1:40 instead I will be a whole lot fresher, even though it is extra 43 minutes on my feet every day. Pace is a very very important factor.

[Steve P]

These two approaches are slightly different, and I don't think there is one right answer. This topic has been debated for decades. Personally, I like changing up the mileage, and if I felt I had to do the same distance almost every day to be successful, running would be less enjoyable for me, and I might quit out of boredom. Others may find comfort in repetition and familiarity each day. As long as we get consistent volume in our training, which I think is the key principle here, the differences in performance between either approach would likely be minimal.

[Jon Allen]

Well said, Steve.  We know Sasha enjoys his daily repetition (often down to the same route).  Other's enjoy variety.  Whatever works for you and keeps you running is great.

[Sasha Pachev]

For me the boredom increases in proportion to the distance. That is one reason my long runs are significantly faster than my normal daily runs.

[Rhett]

I know I was proven wrong with all the above science, that my running just 3 days a week with two runs between 12 and 14 miles and one around 20 is not the best way to train, but for the record it worked for me.  I just PR'd Boston with a 2:58:03 and have not run more than 3 days in a week in over a year.  Just shows there is no one right way to train for everyone.

[Steve P]

Way to go! And good to know this worked for you.