I went to the Run Across Texas Camp and I hear the North camp is a great one!
Well the SI and PI phases do vary depending on season. For instance, this cross season we did the base phase (ppm program) until late August. What we aim for is to run a very fast time on the lppm to try to get to intervals. The lppm base determines what each SI pace will be. For example, I did an 8 mile ppm at 5:17 pace, this then translated into a SI range of 71-75 seconds per 400. I don't know the exact calculations because my coach has them in a binder but I know the SI pace is based off the lppm pace. Say you don't have a great week of ppms and you run a slower lppm than normal, what you would do is just do another week of ppms to try and run a fast time to have a fast SI pace. It's mostly the coaches decision and him trying to judge whether or not he thinks the lppm time is good enough to get a good SI pace. As for the time between intervals the rest is jogging, NON-STOP. Emphasis on non-stop haha. The rest is the most important part of the interval in a sense. The pace of the rest is supposed to be fast. For us our resting pace was at about 6:30 pace, in retrospect our CT pace was around 6:00-6:05. There is no set pace for the jog but to get better the jog should be fairly fast. On the first week of SI the runner must go at least 4 minute jogging rest before starting the next interval. On the second week, and on, the rest is based on the heart rate of the athlete. The runner must check his/her own heart rate and once it is 120/60 you start your next interval. What happens is eventually your resting time will decrease and that is when you know you are getting in better shape. Anything above 120/60 when you start and you begin to go into lactic acid and anything below and you aren't maintaining the oxygen delivery system.
Yes cross is a little different progression of the SI and PI phase as would be track. Since track is more speed oriented the progression is the same just quicker. So you're going to spend less time on the ppm program to get to SI and then PI faster.
Pace intervals is essentially just adding one more speed day to the normal SI week. So normally what happens is on your first week of SI you have a "low set" of intervals say on a Monday. The amount of intervals on the low set is the mileage of the lppm you ran (8 mile ppm = 8 intervals on low set). Then the next 2 days (Tue. and Wed.) are Ct's (based off of the lppm pace to get to intervals). Thursday would be a "high set" of SI which is just adding 4 to the low set (low set 8, high set 12). Then Friday would be another Ct. During season most meets are Saturday (so race day Sat.) and then Ct Sunday and repeat for the next week. Every week of SI you increase by 1 for each the LSI and HSI. We normally only do this for 3 weeks so we end up adding 3 to each SI day (8-11 and 12-15). Be careful moving up with the intervals though because it really takes a runner who has a large running base under them to be able to move up that much on the # of intervals. You do this only for the SI though the PI are always the same #.
The first week of SI what happens is on the low set say, after your intervals, you do 3 all out 100's. This gets the legs used to going fast and also gets you a 100 time which you use for the 2nd week of SI. On the second week of SI, low set day, after the intervals you again do 100's but this time you have a range (fastest 100 time from the week before on the low end and then + .5 sec on the high end). Ex. 12.00 for fastest your range would be 12.00-12.50. You do the amount of lppm mileage for amount of 100's (8 mile ppm = 8 100's) or until you are out of range. There is nothing wrong with getting out of range it just it to estb. a pace for the PI 200's.
So that is the first 2 weeks of SI, then on the third week is when you begin the PI 200's. You take your 100 time to know what your 200 range should be. Again I don't know the exact conversion and my coach has that table.
The PI 200's you do the day after your low set. (mon - lsi, tue - pi 200, wed - ct, thurs - ct/hsi, friday - ct/hsi, sat - race, sun - ct) When it comes to thursday and friday it is up to the coaches decision whether or not the runner needs 2 recovery days in between the PI and HSI. Personally, the PI day is easy on the legs because it is just speed work and I feel I can recover fast. So I would take just 1 ct then do my HSI on thursday. Everyone reacts differently so it's based on the athlete. The amount of PI 200's is based off the lppm (8 mile ppm = 16 pace 200's). The rest between is walking. What we do is start at the 50, run to the 250, then walk back across the middle of the track so about a 100 meter walking rest. Since it is not an aerobic workout the rest isn't as important. And you may notice that you might do a HSI the day before a race. Yes this is true, we normally try to run the HSI in the morning > 24 hours before your race. Some people think its crazy to do interval work before a race but it actually opens you up much better for a race then just taking an easy day. Again some people react differently and like to do a HSI on thurs. so they can CT fri. and race sat. Just depends.
In cross we normally do 2 weeks of 200 PI before moving up to 400 PI. In track it would be 1 week because you are trying to progress faster because there is more focus on speed work. Pace 400's is again based on the lppm (8 mile lppm = 8 pace 400's). The rest between each 400 is standing. The athlete must take his/her heart rate and once it is at 120/60 you start your next 400. After 4 you have an 800 meter rest. First lap is walking and second lap is jogging. Once the 800 rest is finished you wait 45 seconds (standing) and then repeat what you did for the first 4. You must stay in a 4 second range for all the 400's. If you are out of range once it is fine, twice in a row you most then go down to 200's. So say I run 4 400's and they're all in range, if I then have my 5th and 6th out of range (high end) then I must continue the workout but just on 200's. So if I have 2 400's left I would just do 4 200's to finish the workout. Personally the 200's are much easier than the 400's. You're never really going to get out of range much on the 200's but it is more likely in the 400's.
As for CT mileage on the SI and PI program. It is all based off of the mileage level the athlete is on going into the SI and PI. Say I'm on the 60 mile week going into my SI and PI. I would then need to adjust my CT's to ensure I get in 60 miles for the week. You WOULD include warm up/cool down mileage for the SI and PI when calculating your total mileage for the week. The CT's can be adjusted as such. The CT's need to be as close to pace as possible because if they aren't than the oxygen system will begin to decline.
I know it is confusing and there are many things that go into doing the SI and PI properly. The PPM program is where you build the system, and SI and PI is where you fine tune the system.