The Tempo Run is typically one of the first quality sessions added to the base phase and can be maintained throughout a complete training cycle. Tempo Runs can range in effort depending on the goal race distance, nevertheless, these workouts should be performed fairly close to race pace. Tempo Runs can serve as an indicator workout with regards to how you are progressing throughout a training cycle. I recommend using the same course a few times throughout a training cycle.
When: Base phase and pre-competitive phase
What: Medium to longer length at a smidge below race-pace
Where: Somewhere you can run without stopping or have to worry about uneven footing
Why: To improve lactate threshold
4-6 miles at lactate threshold pace