The most important of the speed/quality workouts is designated as the primary workout (and is usually the first workout of the week). The other speed/quality workout is designated as the secondary workout. What is actually done in each of these workouts depends on the phase of training. See the runbayou website for phase details (www.runbayou.com).
For example: Suppose we're in Phase 2 of the program (repetition phase). The primary workout might be 6x400s at repetition pace. The secondary workout might be a 20 minute tempo run. And the long run might be done on Saturday or Sunday. We'd do the primary workout early in the week (to make sure we get it in), run easy for a day or two, do the secondary workout, run easy for a day or two, and then do the long run.
Okay; so far, so good. Now the exceptions.
- If circumstances dictate you can only do one speed/quality workout during the week, do the primary workout.
- If you're going to race on the weekend, skip the secondary workout during the week.
For example: If your race is on Saturday, you might do your primary workout on Tuesday or Wednesday. Take it easy for a few days and then race. Skip the secondary workout.
- What about back to back speed/quality sessions during the week?
For example: Suppose your schedule says speedwork on Tuesday and Thursday and a long run on Saturday. What happens if you miss Tuesday? Can you do a primary workout on Wednesday and secondary on Thursday? This is a tricky situation and requires a lot more individual information. That said, this can be done in some situations but certainly not on a weekly basis. With very few exceptions, I would not recommend it. It would be better to put an easy day between the speed sessions and move your long run to Sunday.
That's it for now.
Good running and have fun.