Looks like there are two threads going on the same subject.
When I trained for the Games I decided to use short intervals up to 400 meters. 95% ws run on grass and the 5% was on a cinder track when I did timed 400's, usually on a Sunday, every other week, beginning in April of 64. 20 x 400 with 60 meters walk and 60 meters jog between each. 3 in 60 seconds and each fourth in 58. I ran the 20th all out and was always in :54 something. All on a cinder track.
In the a.m. at 5:30 I did 72 times a distance. 50 to 60% were 100 meters at different speeds and 150's and 200's at different speeds for the other %.
In the afternoon it was 150, 200, 300 and 400 meters at different speeds. Normally three sets back and forth on a grass field. 10 times 100 meters between each set. Somewhere between 9 and 12 miles in the afternoon depending on how I felt.
The question is do I or have I ever trained my athletes in the same manner. Only in the afternoon and then only three to four days a week. Runs of various distances and tempo's for other days.
Why? I enoyed the intervals at the time but it was very difficult