[This post is still in rough draft form.]
I was going to start with Arthur Lydiard, but that would require a second introductory post, so instead, I'm going to lead in with the proponents of long slow distance. Joe Henderson wrote "Long Slow Distance: the Humane Way to Train" in 1969 and "Run Farther, Run Faster" ca. 1980 and Ernst Van Aaken wrote "The Van Aaken Method" in 1976. I haven't read any of those in 30 years, so it's going to be impossible to discuss them fairly. I'll try to give an idea of the LSD method of training, however. Oddly, Henderson's book "Marathon Training" (1997,2003) has little useful information.
First a thought experiment. Imagine that you run exactly 5 miles in exactly 40 minutes every day for a year. This workout is completely comfortable, but you cannot improve, as you always do exactly the same run. Now, if you make one run per week 6 miles at the same pace, it's difficult at first, but becomes easier and your fitness improves slightly. If you later make that 6 miler 7 miles or make another 5 miler 6, you improve again. As long as you keep running further, you improve in fitness and eventually this improved fitness means that, if you ran 5 miles comfortably, you'd do it in less than the 40 minutes you used to take. In theory, one can improve indefinitely, without ever having to run fast.
Millions have attempted to do just that. It doesn't work very well for most runners, for a number of reasons. Van Aacken, recognizing that one ends up running the longer runs slower, had runners increase their mileage by running multiple times per day (all I really recall was that he had top 10K runners run a 10K four times per day). As odd as this sounds, Gerry Lindgren, one of the most talented 10K runners of all time, ran an average of 250 miles per week for a decade just this way in the 1960's.
To compare training regimens, I'm going to limit myself to the marathon and when possible, specifically to those running 2:15 - just because it's convenient. I'll try to write a typical schedule based on my own work following each method in turn.
Very Boring (and skippable)
When I started looking at training, I did it empirically, seeing how people trained who weren't following someone's plan (something perhaps impossible to do today). Marathoners, regardless of finish time, averaged 75 minutes of running per day (70-80 was common, 65 or 85 the extremes) and their longest run was 165 minutes (150-180 common, 135 or 195 unusual). At the 2:15 level, runners average training pace was one minute per mile slower than marathon race pace and 80% effort (ie, if one can race 10 miles in 60 minutes, a training run would be 10 miles in 60/0.80 or 75 minutes). Runners also raced 4-5% of their total miles, with half the time as a racing season, so 8-10% raced when racing. Additionally, runners usually spaced their races so that there was 1-2 days per mile raced between races.
It just happens that 80% of 2:15 turns out to be close to 165 minutes, so one could comfortably run a marathon for a long run at this level. One possible way of training would be to run a marathon every single day. The secret to doing this is racing oneself into shape. After two weeks of training one would race a 20K, then two weeks later a 25K, then a 30K and finally a marathon, with only the marathon being run all-out. This has one racing a marathon every 8 weeks, which with this mileage is possible for a long time. The problem, however, is obvious: almost no one can run that many miles without injury. Also, it's not a method that any runner not planning on running a world-class would have time to do.
An alternative that fits in better with my own ideas is:
M: 150-165 min.
T: 0-30 min.
Sa: 150-165 min. or race (20-25K on 4th week, Marathon on 8th)
This makes for a manageable amount of work per week, but has some other built-in problems.
The whole point to this post is to give a contrast ot Lydiard's method, which has often been confused with Long Slow Distance training. That almost no one any longer follows the LSD method does not mean that it has no merit, but it cannot be recommended.
Going up the country
20 hours ago