Hone Your Marathon Speed Endurance with Speed-First Training

Run your target marathon pace by developing basic speed before anything else.

Woman sprinting across asphalt

Adapted from the book The Endurance of Speed by Jason R. Karp, Ph.D., MBA

I once coached a 33-year-old runner who ran a 2:48:39 marathon on 80 miles of training per week. Soon after she ran that time—she just missed the then-qualifying time for the U.S. Olympic Marathon Trials by 39 seconds—she joined a sponsored running group with a coach. The coach told me, “She can run mid-2:30s.”

After coaching her in person for two years and seeing what she could do, I was skeptical that she could run a marathon that fast. To do so, she would need to be able to run 5K in 16:00 to 16:15. At the time of the conversation with her new coach, her 5K personal best was 18:08—and that was after a lot of training.

Oftentimes, runners’ performances plateau not because of what they do, but because of what they don’t do. And one of the things that many people fail to do when they start running as adults is work on their basic speed. They never become fast runners.

What happens when runners take the traditional model of distance running training and turn it on its head—training speed first before training endurance? What happens when runners train at the right (target) speed rather than training the target distance?

At first glance, the notion of speed training for a marathon is ridiculous. Anyone who has employed traditional marathon training methods has likely experienced how running more miles, even when those miles are run slowly, leads to a faster marathon.

The concept of speed seems so contradictory to the long haul of the marathon as to deserve little interest. Ironically, it is just this contradiction that demands the concept be considered. It is often when there is a contradiction—by doing things differently than how you normally do them—that breakthroughs occur.

Focus on speed first for speed endurance

There are several reasons to train speed first for long-distance races. To start, it ensures that the training becomes more specific as the race approaches. Long runs, acidosis (lactate) threshold runs, marathon-pace runs, and higher overall mileage is more marathon and half-marathon specific than are VO2max interval workouts and speedwork.

A more traditional approach to training means the volume is reduced while intensity is increased as you get closer to the race. In contrast, with a speed-first approach, you start with higher intensity and decrease the intensity over time as you increase the volume, thereby doing more race-specific work as the race approaches.

Secondly, in my experience, speed-first training gives you an increased speed reserve, which makes pacing easier and enables you to run a faster marathon or half-marathon.

Thirdly, the speed-first approach recognizes that VO2max increases with anaerobic training and that VO2max should be maximized before training the fraction of VO2max that can be sustained.

Even though VO2max is considered an aerobic factor that represents the maximum volume of oxygen the muscles can consume per minute, it is often unrecognized that the running speed at which VO2max occurs depends largely on anaerobic metabolism.

In other words, when you rev your aerobic engine as fast as it can go, your muscles also rely on anaerobic metabolism to run at that speed. Research has shown that the amount of time individuals can sustain exercise at VO2max is positively correlated with their anaerobic capacity. In other words, individuals with a larger anaerobic capacity are able to sustain exercise at VO2max for a longer time than those with poorer anaerobic capacity.

This same research found that sprint-interval training itself improves VO2max—primarily via muscle fiber recruitment and muscular metabolic mechanisms—supporting the significant role that anaerobic fitness (speed) plays in VO2max and distance running performance.1, 2

The improved anaerobic fitness gained from speed training also makes the more metabolically demanding VO2max workouts seem easier.

Finally, focusing on speed first improves running skill and running economy (the amount of oxygen used to run at a given submaximal pace), both of which enable you to handle and even thrive from training, from what I’ve seen with athletes. Workouts in subsequent phases of the training will also feel easier and more fluid as you master your running skills.

The endurance of speed method

To train the endurance of speed, focus on developing basic speed, marathon-specific work closer to race day, training at the right speed, and interval training with high-volume reps.

1. Initial development of basic speed to become a faster runner

Most marathon training programs neglect the development of speed, instead focusing on the weekly mileage and duration of the long run. Most runners and coaches think that sprint training while prepping for a marathon is a waste of time. They believe that because the marathon is 100% aerobic, the training should also be 100% aerobic.

Logically, that makes sense. However, if you never devote any sprint training time to develop your basic speed, you’ll limit how fast your marathon can get. If someone cannot run 6:00 for 1 mile, they cannot run a 6:15 marathon pace. That’s impossible. So, if someone wants to run a faster marathon, ultimately, they will be limited by their basic speed. The best marathon runners in the world are also quite fast at 1 mile. And if you never train your fast-twitch muscle fibers, you can never rely on them for the power they produce or the fuel they store. When you become a faster runner, your marathon pace will feel easier, and you’ll be able to run a faster marathon.

2. More marathon-specific work as the race approaches

By starting with higher intensity and progressing to higher volume instead of the other way around (as is typical of most marathon training programs), you do the most marathon-specific work at the time you need it. The decrease in intensity with concomitant increase in volume doesn’t mean the training gets easier, only that the emphasis shifts toward marathon-specific endurance.

3. Training at the right speed rather than at the right distance

Runners and coaches often make a big mistake when marathon training: They fail to consider the demands of the race, which means they also fail to get specific in their training to meet those demands. There’s not much value in running long and easy all the time, since that is not specific to running a fast marathon.

After years of running, much more of the marathon runner’s training should be specific to the demands of the marathon. It’s much easier to run at 90% of your maximum speed if your baseline running is done at 80% rather than if your baseline running is done at 60%. It is easier to improve endurance than to raise the intensity (which requires an improvement in speed).

It is also much easier to extend a familiar intensity than it is to introduce an unfamiliar intensity. How you accomplish this is by increasing the volume of intensity—the volume of specific workouts and the volume of running at marathon pace. The goal is to be able to sustain your target marathon pace for longer and longer periods of time—ideally, for the entire 26.2 miles. This process takes months to years, not weeks.

4. Interval training with unlimited reps

Nearly all coaches prescribe—and nearly all runners perform—a specific number of reps during interval workouts. That number is almost always decided before the workout begins. However, the number of reps is not all that important and is usually an arbitrary decision. There’s no magic in doing five, six, or 10 reps. What is important is causing fatigue during the workout, because fatigue is what your body responds and adapts to. Do as many reps as it takes to cause a sufficient amount of fatigue on that day. In other words, until you feel like one more rep would be absolutely exhausting.

Beyond the physiological reasons for training with unlimited reps, there are psychological benefits: You avoid limiting yourself. If you focus on one rep at a time without any preconceived idea as to how many reps you’ll do, you’re forced to stay in the moment and focus only on the rep you’re running. When you do that, you may end up completing the workout running more reps than you thought you could.

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5. Interval training with a high volume of reps

Running many miles per week is a great (and necessary) way to build general endurance, but not specific endurance. To build specific endurance—the endurance of speed—you need to run faster paces for longer.

And one clever way to do that is to break up your interval workouts into shorter reps so you can do more of them and spend more time per workout at a given intensity. The shorter the distance run, the more total distance (and time) you can complete in the workout at the same pace.

To become a faster runner, start by running faster. And then train the endurance of speed.

How to train the endurance of speed

Speed-first training is divided into three phases: General Preparation, Specific Preparation, and the Taper. The General Preparation phase is made up of four training cycles and emphasizes anaerobic power and anaerobic capacity.

The Specific Preparation phase is made up of five training cycles, emphasizing aerobic capacity, acidosis threshold, and marathon (or half-marathon) pace.

The latter part of the program includes more race-specific endurance training as you approach your marathon or half-marathon race to improve your ability to maintain a high fraction of the speed you trained in the General Preparation phase.


  • Speed (Anaerobic Power) and Speed Endurance (Anaerobic Capacity)
  • Weekly Mileage: 55-70% of peak

Training Cycle 1

Emphasis: Speed (Anaerobic Power)
Weekly Mileage: 55% of peak

Very fast sprints for 5-20 seconds, with standing/walking recovery intervals of 3-5 minutes.

Training Cycle 2

Emphasis: Speed Endurance (Anaerobic Capacity)
Weekly Mileage: 60% of peak

Long sprints of 30-90 seconds, with jogging recovery intervals at least double the length of time as the reps.

Training Cycle 3

Emphasis 1: Speed Endurance (Anaerobic Capacity)
Emphasis 2: VO2max (Aerobic Power)
Weekly Mileage: 65% of peak

Hard runs of 3-5 minutes at or very near 100% max heart rate (about 6-9 seconds per mile faster than 5K race pace, or about 15-18 seconds per mile faster than 10K race pace), with jogging recovery intervals slightly less than or equal to the time of the reps.

Training Cycle 4

Emphasis: VO2max (Aerobic Power)
Weekly Mileage: 70% of peak

As above, hard runs of 3-5 minutes at or near 100% max heart rate (about 6-9 seconds per mile faster than 5K race pace, or about 15-18 seconds per mile faster than 10K race pace), with jogging recovery intervals slightly less than or equal to the time of the reps.


  • Acidosis Threshold and Marathon Pace
  • Weekly Mileage: 75-100% of peak

Training Cycle 5

Emphasis 1: VO2max (Aerobic Power)
Emphasis 2: Acidosis Threshold
Weekly Mileage: 75% of peak

Comfortably hard runs at 85-90% max heart rate (about 15-18 seconds per mile slower than 5K race pace or about 9-12 seconds per mile slower than 10K race pace).

Training Cycle 6

Emphasis 1: Acidosis Threshold
Emphasis 2: Marathon Pace
Weekly Mileage: 85-90% of peak

Runs at realistic goal marathon pace, extending the amount of time to sustain the pace.

Training Cycles 7, 8, & 9

Emphasis: Acidosis Threshold
Emphasis 2: Marathon Pace
Weekly Mileage: 90-100% of peak

Runs at realistic goal marathon pace, extending the amount of time to sustain the pace.


  • Marathon-Specific Endurance
  • Weekly Mileage: 30-50% of peak

Workouts are of the same intensity but of a lesser volume than what was done during the Specific Preparation phase.


  1. Faina, M., Billat, V., Squadrone, R., De Angelis, M., Koralsztein, J.P., and Dal Monte, A. Anaerobic contribution to the time to exhaustion at the minimal exercise intensity at which maximal oxygen uptake occurs in elite cyclists, kayakists and swimmers. European Journal of Applied Physiology, 76:13-20, 1997.
  2. Sloth, M., Sloth, D., Overgaard, K., and Dalgas, U. Effects of sprint interval training on VO2max and aerobic exercise performance: A systematic review and meta-analysis. Scandinavian Journal of Medicine & Science in Sports, 23(6):e341-e352, 2013.

About the Author

A competitive runner since sixth grade, Dr. Jason Karp quickly learned how running molds us into better, more deeply conscious people, just as the miles and interval workouts mold us into faster, more enduring runners. This passion found as a kid placed Jason on a path that he still follows as a coach, exercise physiologist, author, and TED speaker.

He is the 2011 IDEA Personal Trainer of the Year and two-time recipient of the President’s Council on Sports, Fitness & Nutrition Community Leadership Award. His REVO₂LUTION RUNNING certification, which has been obtained by fitness professionals and coaches in 26 countries, was acquired by International Sports Sciences Association.

In 2021, he became the first American distance running coach to live and coach in Kenya. The Endurance of Speed and his other books can be found on Amazon.