I will try to answer some of your questions:
The boys are 18 and 17 years of age. For the past 3 months they have averaged 80k (50miles) and 60k (40miles).
We are 5 weeks away from our National Athletics Championships. Both boys have good speed but are not super fast. 400m speed would be around 51-52 for both. Both will be threats to win Nat'l medals in 1500m in April and have in the past.
I have a large group of athletes with varying levels of ability.
Question about why weekday runs in minutes and weekend specific? It is hilly where we are and I just want them to get out for time. On Weekend long run the course we do is flat so easier to tell them exactly how far I want them to go. I see my athletes 4x per week.
We train on the track once per week usually on Tuesday. Our Thursday session is on grass. Our Saturday sessions vary from a very hilly circuit which we cover between 9-12k, a flatter dirt circuit which we do progressive runs over 10k or back on grass xc course.
Question how do I determine threshold? This is very difficult as many of my athletes haven't raced 10k and most of our threshold efforts are on grass which is slower than track. On grass my 17 year old's threshold pace is around 3:25-3:30K pace and 3:15-3:20 on the track.
Background on athletes 18 year old was recently preparing for World XC Junior trials here and ran 26 minutes on a tough circuit. 6 days later he ran 1:52 and the following weekend ran 3:51. Prior to 800m fastest track work was a series of 200's in 30 seconds and 150m accelerations. Although we have done some very good hill sprint sessions.
Breakdown of training
Mondays for our group is recovery day. Athletes run on their own for 35-40 minutes their pace may be as slow as 4:30-4:50k pace but once again if they chose a hilly circuit that is sufficient.
Tuesday's in December and January have been track sessions with alternations. Pace of most hard efforts is 3k pace with float in between. The focus is still on developing endurance. A few sample workouts 3x4x200/with 100m recovery float 2 minutes between sets or 3x3x300 with 100m recovery both workouts would finish with 150 accelerations ie change of pace every 50m. Two weeks ago our group did 2x5x400 at 75 seconds with 45 second recovery. Early in the season pace work is 3k-5k with most efforts but we keep touch with speed with 150 or 100m efforts. Now as end of season gets closer we start specific work at 1500m pace over 300/400m and 800m pace efforts over 200m /300m. Rest during early part of season is always 1-2 minutes. As more specific to 800/1500 increase rest to 2-3 minutes. Remember these athletes are juniors so never too much anaerobic work.
Wednesday easy aerobic running day 40-60 minutes
Thursday we do hills! We have 5 different hills that we do and they all give the athlete a different training stress. Hill #1 is 60m 12% hill we use this for power and strength, Hill #2 120m hill at 10% is for power and strength but obviously harder than previous one(used more during XC season) Hill #3 100m slight hill 4% can still run fast but allows for good running mechanics. Hill #4 300m hill for lactate tolerance sessions. this hill wraps around last 50m flattens out we do this on a 3 min cycle, Hill #5 100m road hill 10% another great steep hill for developing great strength but because on the road athletes get some energy return.
All of our Thursdays have either a threshold run before or after the hills. I generally like to do hills first then threshold but sometimes have them do threshold before and after. Example recently was 1500m threshold followed by 6x300m hill
Friday OFF or easy jog of 30 minutes
Saturday varies last week our 1:53 runner did 10k progressive run. He finished with a few k's under 3:30 and walked away feeling strong and refreshed from interval work during the week. Now you might think that a 17 year old who run 1:53 and will run soon 3:55 is very aerobically fit but he still can't keep up with my elite female preparing for World XC! He still has room for improvement!
During January a number of Saturdays training included a 10k hilly circuit in which athletes surge hills during the run. If they are doing this the Thursday session may be a shorter fartlek session or longer repeat session.
Sundays are easy running with athletes running between 15-20k or 60-85 minutes although my elite female is run 25k generally
This training is similar for my elite female but her volume is 120-130k per week and her efforts on the track are different with longer reps and longer alternations. She does hills but her threshold efforts are up to 5-6k afterward instead of 1200-2k.
If you have any questions let me know.
Cheers