Yeah for the longest time I wasnt sure of all the lingo, being pretty much self taught. Still a bit uncertain if some of what I do would be called repeats or intervals (my fast runs, where I do maybe 1/2 mile to 1 mile at fast pace, then 1/4 to 1/2 slow recovery, then repeat).
Those McMillan links I posted are the best explanation I've found of runner's lingo and training protocols.
For intervals, my understanding is that they are anything you do below lactate threshold, with walking, jogging, or stopping breaks in between for recovery (to shuttle the accumulated lactate to other tissues to be used as fuel). Intervals can be anywhere from 40-100 yards in distance up to a mile or so, although I suppose you could do two- or three-mile intervals too, as a sorta slightly faster tempo run. Intervals aren't necessarily sprints, but it seems like people are getting that idea lately because of the popularity of Tabata intervals in Crossfit type programs. Or maybe it's the use of the word "interval" after "high intensity" in HIIT (High Intensity Interval Training) programs.
I just started doing intervals late summer/early fall last year, then stopped over the winter, so I'm still finding my way with them. Seems I like to do 440 and 880 intervals mostly. Yesterday I was going to do one-mile 'cruise' intervals, using my pace alert set at 8:30 mm. I haven't used a pace alert for a long time. But after the first mile I turned off the annoying alert, took a pee in the bushes, put on an old jam to listen to, and just ran. I clicked the lap button after each mile, except the last two, but other than that didn't pay any attention to my Garmin. Funny, miles 3 and 4 were the slowest. I picked up steam again once I switched to grass. Running on grass is really pleasing, such a different sensation. It had drizzled earlier in the day, so both the track and the grass were nice and cool.
I usually use simpler terms, fast day, long day, trail day.
Okay I do more than just those, but I really don't follow any training plan or even within the run I might change stuff up.
Yah, I use what I've learned as guidelines, but my overall approach is still pretty lackadaisical. I like to think about my run earlier in the day, to get psyched for it, but I often change plans once I'm out. My only real training plan is to get better. Right now I'm flirting with the idea of just running tempo, intervals, and hills until my endurance pace picks up a bit, but then I'd miss those little urban adventures I get from LSD runs.
I also tend to think of the runs as fast, medium, and slow, corresponding to intervals/hills, tempo, and LSD runs, corresponding to anaerobic, lactate threshold, and aerobic. Triads rule!