Here is a link to an article written by Juantorena about how Juantorena trained:
http://www.athleticscoaching.ca/default.aspx?p=search&s=juantorena
You have to sign up with the website but they have lots of good stuff, some free, some not.
Here is a link to the BMC News which has Tom Courtney's training on page 6:
http://www.britishmilersclub.com/bmcnews/2002spring.pdf
Plenty of 300s and some 1200s.
Here is Renato's discussion of the training of Marcello Fiasconaro (first guy under 1:44, also ran 45.5):
I had a personal experience with Marcello Fiasconaro. In 1971-73, I was the assistant coach of the Italian responsible for 400m / 400 hs / 4x400 (Salvatore Morale, in 1962 winning European Championships in 400 hs with the WR of 49"2, and in 1964 bronze in Olympic Games), and I was the first working in Italy with Marcello, coming from South Africa. He came Italy on 28th June 1971 with a PB in 400m of 45"9 (Italian Record) in South Africa, and ran his first Italian competition winning, on 1st July, his 400m during the meeting "Notturna di Milano" (in the same occasion, Marty Liquori beated Franco Arese in the fastest 1500m of the year, 3'36" vs 3'36"3). After few days (we had a training camp in Viareggio) we had a match against Cuba, and he ran 400m against a new Cuban (Alberto Juantorena, very young and in Europe for the first time). Marcello bettered the Italian Record with 45"7.
Morale sent me as responsible for a period of 2 weeks in altitude (Abetone, 1800m) without any track, with the athletes of the relay. One day, I went running 30' fast with March (nobody of the other 400m runners in Italy was able to stay with me) and he was very comfortable with my pace. I remember I told him "you must try 800m, you can become the European Record Holder", and he told me "I never want run 800m, are too long".
In European Champs (Helsinki) March won the silver medal in 45"49 (NR) behind Dave Jenkins, and in the relay Italy won bronze medal for the first time in its history.
In 1972 March had a stress fracture in the navicular bone of his left foot, and in OG he couldn't run. This happened because of the first syntetic tracks, so at the end of September he went to Johannesburg, and in December started training on grass under the programs of Stewart Banner,a coach owner of a chain of restaurants.
Increasing his long run till one hour 3 times per week, and using long intervals (400-600m) during the other days, he bettered 3 times the Italian Record of 800m (1'45"7 / 1'45"2 / 1'44"7) in epic duels against Malan and Botha. He came to Italy at the end of March.
I organised for him in Turin morning training sessions on the Golf Field in La Mandria, and March went there 5 times per week, running every day 10 km between 35' at the beginning of the period and 33' at the end of May. On the track, his program was very easy : twice per week (Tuesday and Friday) alternating this type of workouts :
a) 10x150m in 18" with 2' recovery
b) 6x300m in 36" / 36"5 with 6' recovery
c) 3x600m in 1'21" / 1'19" with 8' recovery
d) 6x150m in 16"5 with 5' recovery
e) 3x300m in 33"5 / 34"5 with 8' recovery
I remember that the week of the WR (he ran 1'43"7 in front from the first meter with splits of 50"1 / 1'16"5) he ran, 5 days before, on the track (earth) of the Club Fiat, 3 times 600m in 1'18"7 / 1'19"2 / 1'18"8 with recovery of 8' between the first 2, and 10' between the second and the third. I remember also that after the second he was very tired, so I advised him to run slowly (about 1'23"), and I asked to another runner with a PB of 1'51" to pace him for the last 300m in 41". But this athlete, fearing to run too slow, started when March was still 15 meters before the line of 300m (he ran the first 300m in 42"), running very fast. March, that didn't want to lose also in training, started to increase his speed, and overtook the other athlete with 10 meters to go, running the second 300m in 36"8 !
Read more:
http://www.letsrun.com/forum/flat_read.php?thread=4030549&page=9#ixzz2GRSTNIa5