Whenever you have an event time goal, your entire training program should be focused toward achieving the ability to sustain your target pace in that event. This doesn't mean you should always run at your target pace, of course. But it does mean you should include some target-pace running in your weekly training throughout your training program and do a fairly large amount of training at or near your target pace in the final weeks before your event.
In addition, the rest of your training—that is, your workouts at slower and faster pace levels—should support your objective of achieving the ability to sustain your target pace.
The reason target pace training is so important is that the body adapts very strictly to the specific exercise demands that are placed on it. One ramification of this principle of specificity is that your body will adapt well to running at your target pace if you regularly train at your target pace. It will achieve greater metabolic and neuromuscular efficiency and better fatigue resistance at this pace. And on a psychological level, you will also find it to be more comfortable.
Before you can train at your target pace you must, of course, choose a target pace, which means you must choose a goal time for your event.
In my experience, most runners are pretty good at selecting appropriate goal times. There's no need to complicate the process with a lot of pseudo science. If you've raced previously at the distance of your goal event, these performances will obviously provide a solid foundation for goal setting.
Once you have established a target pace, it's time to integrate target pace training into your training plan. How you do so depends on the distance of your goal event. If you're training for a short race such as a 5K, your target pace training should take the form of short intervals in the early weeks of training. Your target pace intervals should become gradually longer as your fitness improves.
Here's an example of a target pace interval workout progression for a 5K runner in a 16-week training plan:
|Weeks 1-4||10-20 x 200 meters @ target pace 30-second jogging recoveries|
|Weeks 5-8||6-12 x 400 meters @ target pace|
|Weeks 9-12||4-8 x 800 meters @ target pace|
|Weeks 13-15 |
(week 16 is an easy, "taper" week)
|4-5 x 1K @ target pace 3-min. jogging recoveries|