Trackhead and Coach Duke
For me, the final answer to the benefits or prejudices of 2 hour long runs for 800m-1500m middle distance events, or for 5000m and 10000 events and also for the marathon event -that´s i know not by science argument or justification, but by mainly by real performance results - that are facts.
Ok, there are 2 large groups: those who do 2 hour long runs and those who don´t. take a look for national rankings, internacional ranking season PB or all time PB - and we will see thar´s a VAST MAJORITY that tends for those that don´t do long runs they are at the top of 800m-1500m-500m-1000m lits at any class that you want consider.
But if we do the same "exercise" to those who do workouts or those who don´t, or those who train more than 100miles and those who train less; or to those who do taper for peak shape, or whatever you want relate with the perfromance you can´t take such a conclusive answer that you will take about the use 2hour long runs or you don´t.
The case is that in running history it did happen that long ago a great long from the english language (don+´t forget that) did a tremendous sucess with a few of their top class runners - that´s Arthur Lydiard with Halberg, Snell, Dick Taylor and more. It did happens that that coach did prescribe 2 hour long runs for their runners event for 800-1500m. Of course that many other they copied that Long one - and also did and do some sucess - but that´s not enough. The large majority in europe or all over the world get their targets without including the long run in thier schedules.
To try to justify the use of long ons by science arguments when here we are with top rankings to dismiss completly the profits or benefits of that use seems to me unrealistic, not factual.
But if you look to a marathon ranking or a marathon olympic classification it happens the opposite. There´s a large majority of the top runners that they all use long runs - but even those ones - they use that mainly in the specific marathgon training periods and not all season long.
Now i ask in the opposite direction. That will be enough to justify that 90 minutes that´s enough for a marathon specific plan just because one day Carlos Lopes did win marathon olympics or did the marathon WR but he never did more 90 minutes runs - and even that very rarely? Of course not !
Please, look for the rankings at any level of categories. Look for meetings performances and big games results.
Look for the figures, numbers, statistical range avarages. That´s accurate than scientific arguments. Besides that´s the transfer of training concepts and training use to the reality.