-tmk is right about HS kids. I work with several who are in programs that have a history of less than stellar distance running. In Colorado runners can qualify for state by time. The "qualifying" meets are designated in advance (not all meets are qualifiers). One sophomore I am working with started his season running a 2:12, 4:50 and 10:20 triple at his first meet in March. By early April he had run 9:50 (9:57 qualifies), 2:06 and this last Saturday a 4:27 (4:28 qualifies) and I expect to see more improvement by the May 20th state meet. All of his qualifiers were in meets where he also ran the other two distances. We focused on specific distances based on his racing performances (hard time with pace of the mile, next meet focus is the 800, problem with holding pace in the mile, next meet focus running negative splits in the 3200). He also then came back in one meet ran a 9:53 for 2nd while pacing two teammates to 9:57 (qualified for state with that) and 10:08.
The other group includes 3 ladies. Two had broken 20 for the 5 km in cross country, the 3rd was at 22. They started the season running 2:40, 5:45 and 12:20 to 12:10, 5:58 and 13:00. They are now running 2:28, 5:22, 11:30 to 2:38, 5:40 and 12:20. Two of these three are sophomores. As with the guys above, I expect that at least one more of these 3 will qualify as individuals (requires 5:17 or 11:37) and they have a chance of making it in the 4 x 800 relay with these 3 and another 800 runner who is approaching 2:40.
Both sets of these youngsters do weekly runs of at least 90 minutes up to 120 and a second run of 75 to 80 minutes with a 20 minute threshold run in the middle. These are not exceptionally talented kids. They are just doing the running to develop their endurance. Then using a straight Lydiard approach to work toward state qualifiers and when they get there, they will be rested and ready to race.
Glenn