little red,
it's all in how you do it. For beginners, after they've got a little running in them, they can do a few minutes of LT and if they do a race, subtract the race distance/time/effort from the workout during the week.
drop intensity when you bump, once you're established at hte new volume you can bring it back up.
As they increase training volume, volume of intensity can go up. If you keep a rule of now more than ~15% of the week can be hard (including ALL running), you limit the risk of injury or burnout. If they're runnign a 30mi week, they have ~4.5mi of hard running they can do. When they're training more, years later, like 60mi weeks, that allows for 9mi of hard running.
If you keep everything as a percent of their totla volume, the kids will be fine.
here is a sample peak week schedule:
peak week
Sunday - 16mi run
Monday - 8a-3p school, 20min warmup 16x60m w/ 340m jog, 20min cooldown (9mi, probably 2hr workout)
Tuesday - 8a-3p school, 20min warmup, 6x1mi w/ 60s rest, 20min cooldown
Wednesday - 6:30am 45min easy, 8a-3p school, 60min easy
Thursday - 8a-3p school, 20min warmup 20x200m @ 1500m pace w/ 200m@90s rest, 20min cooldown
Friday - 60min easy
Saturday - 2mi flat, 4mi up Mtn., 4mi down, 4mi flat.
Total: 80.5mi
miles @ intensity: 13.1
percent of week @ intensity: 16.3%
Overall, the week has relatively little intensity.
Sunday is long, but not high intensity. It can't be because they won't be able to do much for the rest of the week. That's the value of speed limits.
Monday is long, but very low intensity. They're at 400m effort for 8-10s and then jog for 2.5 min. Nothing big. It will make you sore the first few times you'll do it.
On Tuesday these most advanced kids are running ~40min at half-marathon/marathon effort (this is nothign new, remember we began with just a few minutes of broken up running).
On Wed. they have one double day (remember these are advanced kids; the swimmers do two a days for beginners) and everythign is very very easy.
Thursday is a big endurance workout, because it's long. They end up averagin slower than 8min/mi space, and their running for 30-4x's at 1500m effort with a 90s 100m jog. Very low intensity; it's when you either lengthen th einterval or shorten the rest that it starts becoming hard.
Friday is very easy running or a day of no running.
Saturday is a medium effort day, basically spending 6mi of easy flat running, 4mi of medium effort, uphill running and 4mi of very easy downhill running.
As far as racing, it's very taxing and shouldn't be done often. When you do race, subtract the race effort volume from the quality during the week.