There are several camps on this one and for me, it seems, the best way to find out is by reading the literature and talking to people involved in the sport and finally trying an approach over an extended period and determining the improvements or the performance at the target event with your expectations.
There are generally helpful principles and maybe even exact laws but I think that there are many levels of fitness and particular ideas and strategies will only work on particular levels.
In preparation for a long race in the summer, I am running long and trying to stretch those longer runs so that for example my 6 hour run feels normal and my recovery time is reduced to no more than an hour or so.
However these runs are faster than my previous race pace which was somewhere around the 3-3.5 miles an hour range. It is impossible to replicate race conditions so strengthening the body with frequent long runs andÂ shorter runs, 2-2.5 hours plus, at my marathon speed, will over the next 6 weeks at least provide a depth of endurance missing in last years race.
Last year I ran the ran the 72 hour at ATY and then in March went to Houston for the 48 hour.Â After only a few hours at Houston I ha an inexplicable pain in the lower right leg that forced me to walk for almost 40 hours. It took one month or more before I could run again and the longest run from March until June was no more than 18 miles or so and that but once a week generating between 30-50 miles a week. The most frequent run was 6 miles at 85% of marathon pace.
My overall performance in the 3100 was the slowest of all my performances and this is due, I feel, to poor conditioning between January and the middle of May last year despite the long races I ran. Consistent high mileage at a comfortable to easy pace plus a good effort onceÂ a week will build the capacity to be able to raise my mileage rate in the 3100 by a quarter mile an hour.
The long run is absolutely essential for me. Without it, not only do I lack endurance, speed and power but also the legs and feet dont get the conditioning they need to be able to maintain activityÂ for 16- 17 hours a day. Blisters and chafing are weaknesses that put extra burdens on close and associated muscles and areas that also overload very quickly and put extra strain on the hips and the back and the whole exo-skeletal system. Pretty soon the body gets injured and/or has to walk.