Marathon Indicator Workouts
When it comes to the marathon there are many ways to train to reach the same goal. Some will be more successful than others depending on the individual. The variety in training approaches partly stems from the fact that marathoners, including elite marathoners, will race anywhere from 85-95% of their lactate threshold (LT). That 10% difference can have a major impact on what type of training will produce the best results. For example, runners who are running at 95% might respond better to higher volume and a higher volume of marathon-specific tempo work, where those close to 85% would likely respond better to lower volume and more speed work.
No matter what the training involves, though, there must be some clear indicator workouts in all programs of which are so marathon-specific that they leave very little doubt as to what is possible on race day. These include workouts and results like:
18 miles at goal pace
Half-marathon at ½ of goal marathon time minus 10 minutes
6 miles, 5 miles, 4 miles, 3 miles at goal pace with 1-2 min rest in between
Mile repeats, Yasso 800s, or 10k race results also give some indication, but these are only showing part of the picture. If they alone are used to gauge fitness for a marathon, race day might be a bit disappointing. For example, Tom might be able to run 8*800 @ 3:00 with a 3 min rest and therefore think a 3 hr marathon is going to happen, but he never extended a tempo run beyond 10 miles during training, and thus never really became fully efficient at his marathon goal pace. This makes the last 10k of the marathon a guessing game, though the safe bet is the pace will fade.