Good morning,
For me it was 1973-1974. Double workouts Monday through Saturday, once Sunday. High mileage was about 150, with average around 110 per week. Igloi type interval training Monday and Wednesday, with shorter tempos sprinkled in. Saturdays typically featured races or repetitions, large sets of 400s, for example 4 x (4 x 400m @ 62-63 / 200m easy) with 400m between sets. The Igloi interval days featured two training sessions of repetitions, where the daily volume was 20-26 miles. These were the critical days, where volume was marathon specific with speeds exceeding 2:20 pace. In hindsight, there was probably a more effective way to accomplish the goal, I am certain.
Igy