Extend First, Then Intensify
The temptation is to dive right into intense workouts like repeats and long tempo runs, almost with a sense of urgency. And many plans have you start on such work right away, and then slowly build up the quantity—for example, first 4 x 800m, then 6 x 800m, etc. While such workouts have their place, it's important to keep in mind that the marathon is 99 percent powered by your aerobic energy system. Thus, the emphasis should be on developing your aerobic endurance, and that generally comes through volume. And volume is a cumulative concept—having a dazzling peak week with a slow build-up isn't going to be as helpful as getting to a good mileage early in the program and staying there. "Extend" your volume first and then "intensify" the workouts.
Early in the season, focus on building mileage with relatively easy runs, punctuated with regular sessions of strides (short bursts of speed) to develop your running economy. As the season progresses, start introducing harder tempos and repeats, specifically designed to improve your lactate threshold (LT) pace and increase your ability to maintain such an effort. Initially, tempos should be near your lactate-threshold pace—or roughly your 10K pace plus 10 seconds. Marathon-specific repeats should be longer and slower (at lactate threshold pace), and incorporate shorter recoveries than what you might complete when preparing for a 5K or 10K. Example workouts include:
- 5 miles at LT pace, or, better yet, progress from half-marathon pace through your LT pace to finish at around 10K pace
- "Cruise intervals" such as 3 x 2 miles at LT pace, with 2:00-3:00 recoveries between
- 8 x 1000m at LT pace with 1:00 recoveries between
As you get closer to the race, such tempo runs should get more race-specific. These efforts could include long miles at or near marathon pace, perhaps done as repeats like 4 x 2 miles, or 2 x 6 miles embedded near the end of your long run. Such sessions should be spaced out by 10 days or more, depending on such factors as your age, experience or injury history. Dialing your race pace in on longer runs is the best form of race-specific training available, getting you both mentally and physically ready to meet your marathon goals.
Maintain Your Strength and Mobility Work
Over the course of the season, running will take up more and more of your available time. You'll obviously need to find that time somewhere, and reducing strength training or flexibility work may be a tempting place to look. While some reduction is in order, not only to save time but also to focus your energy on running, completely eliminating it is never a good idea, as this can leave you vulnerable to injury.