In my opinion, few things changed in training about short distances (800 - 1500m).
One of the best designed strategies is, without any doubt, the "mathematic approach" of Peter Coe with Seb.
It's not a case that 800m really didn't improve too much in almost 30 years, and 1500m only a little bit better.
Analysing the top 30 performers all-time, we can see the following distribution per year in all the Olympic distances, limited at male events only :
800 1500 5000 10000 3000st Marathon
80 - 90 : 6 4 - - 3 -
91 - 00 : 8 8 7 6 10 -
01 - 10 : 10 13 15 15 8 7
11 - 13 : 6 5 8 9 9 23
How it's possible to see, in the during the 10 years period between 2001 - 2010, we can find the most important improvement under the point of view of QUANTITY, which is a parameter more important than looking at the top 5 only.
Some period was characterized by some champion of superior level. This fact provoked big interested, also in normal people, for track and field, and organisers of the big meetings prepared many competitions for trying to better the WR, with several pacers at very fast and even speed.
Due to this fact, we find "groups" of performances, during the best years, run in the same race : typical example are the 800m of the period 2011-2013, when 5 of the 6 performers improved their PB following Rudisha in Olympics Games.
So, we need to remember that the best improvement of 5000 and 10000m during the period 2001-2010 is mainly due to the presence of Kenenisa Bekele, who increased the interest for the long distances in meeting as Bruxelles and Hengelo, and gave the opportunity to run fast for all the athletes competing with him.
Same thing looking at steeple during the period 1991-2000 : behind Moses Kiptanui, always pacing fast, the athletes had the possibility to enhance their performances, finding perfect conditions for running fast.
Completely different is the picture we can have looking at Marathon.
In top 30, we find only 2 athletes with their best in 2003, and 28 during the last 5 years (2008-2013).
To think that this trend is due to the improvement of external factors (shoes : in many cases were better 40 years ago ; roads : I don't see differences in the quality of tarmac in Fukuoka between 1980 and today ; supplements : about Marathon runners, I think the specialists of 40-30 years ago used more supplements than today), and also, looking at track, the quality of spikes and tracks (tartan existed from 1968, and for long distances continues to remain the best surface), is to refuse the idea that training changed in direction of more volume of quality.
Of course, running is Always "only" running. But little differences in speed must be considered "different means of training", since can provoke great changes in the physiology of the athletes.
This involves a change of mentality, for example : in periods where running 13:00 in 5000 put you out of prizes in Diamond League, who wants to remain a runner of 5000m trains with the idea that 12:50 - 12:55 MUST BE A NORMAL GOAL. When in 1987 Said Aouita went for the first time under 13:00 in Rome, his performance seemed something absolutely superhuman ; today, a lot of athletes running under 13:00 are totally unknown, and finish a season with an income of less than 20,000 USD.
In 1980, there was not the idea to use long intervals on track. A lot of volume with long slow run, many competitions (that saved the shape of the athletes, producing the intensity they didn't use in training), and on track only short distances with short recovery, many times burning the athletes.
I remember an incredible training during the World Universitary Games in Torino (Turin), 1970, with Dick Buerkle running 30 times 400m under 60" (the fastest 58") with 100m recovery jogging in 30" / 40", continuing running (so really 30 times 500m, 15 km on the track), 6 days before the race. In the race, he ran... more than 31' !
About Marathon, Toshihiko Seko used running more than 300 km per week, with a peak of 480 (average almost 70 km per week). During their preparation, Japanese Marathon runners used, may be twice, running 100 km continuously (80 for the ladies), a process they called "mentalizazion".
Now we changed completely these absurd training, having only more the effect to destroy the body structures (because kilometers are in any case consumption for tendons and jointures) without any other benefit under the bioenergetic and organic point of view.
The best Marathon runners in the World run about 200-230 km per week, that is not low mileage, but is not comparable with the mileages of 30-40 years ago.
The big difference : inside this mileage, the VOLUME OF INTENSITY is very much bigger than in the past.
So, the real change of today is not in the volume, is not in the intensity, BUT IS IN THE VOLUME OF INTENSITY. And this fact can also explain why, shortest is the distance, more difficult is to do something new : THE INTENSITY IS ALREADY AT THE LIMIT, and the only room of improvement is to work on the neural situation.
Like example, look at the event of 400m.
In the Olympic Final of Rome 1960 (not synthetic track), two athletes, Otis Davis and Karl Kaufmann, ran the same time (44"9), after 4 different rounds, with qf and sf the same day (one day before the final, without resting day as today). With their times, they could be in top 6 in WCh this year, and in OG last year.
Their training was vey much different from today : not lifting weights, not using specific plyometric exercises, not pulling some tyre, not training twice per day.
But they did the MOST IMPORTANT PART OF TRAINING : for example, 3 times 300m at max speed with 15' recovery, and in any competition there were several rounds. Particularly, in the activity inside the US Universities the best athletes ran 100 -200 - 400 - 110 hs - long jump, and relays, using as training a lot of competitions.
So, no periodization, but a long competition season for developing the specific quality.
Now, athletes do this type of intensity in training, for having time to use a lot of other training systems, following some precise periodization.
But at the end of every talk, what did change in the dimension of performances ?