Marathon Training Series

Week 4 – How Much Speed Work Should You Do?

If there's one thing that can make marathon training confusing, it's speed work. You know you need to run a lot of easy miles. You know you need to do long runs. But then you start hearing about tempo runs, marathon-pace workouts, speed repetitions, hills, strides, and all these different types of training that are supposed to make you faster. You see someone doing mile repeats at 6:30 pace and wonder if you should be doing them too. You hear about another runner doing a 10 mile tempo run and start thinking maybe your workouts aren't hard enough. Then you read about elite marathoners running incredibly fast intervals and suddenly your own training starts to feel inadequate. But here's the problem: speed work isn't about running as fast as you possibly can. And it certainly isn't about trying to copy someone else's workouts. The goal of speed work is to improve your ability to run your goal marathon pace, sustain a strong effort over a long distance, and get the most out of the aerobic fitness you're building through your weekly mileage. That requires a little more thought than simply running fast. Let's talk about how I approach speed work in marathon training, what different workouts are designed to accomplish, and how to determine the right amount of intensity for you.

1. Speed Work has a Purpose

Speed work matters in marathon training. It can improve your aerobic capacity, running economy, lactate threshold, and ability to sustain faster paces. Different workouts create different training adaptations, and the right combination can help you become a more efficient marathon runner. But I want you to understand something important. The purpose of a workout isn't to prove how fast you can run. It's to develop a specific ability that helps you become a better marathoner. If we're training for a marathon, I don't necessarily care whether you can run one mile at a pace that's much faster than your goal marathon pace. What I care about is whether you can sustain a strong, controlled effort over the distance you're preparing to race. A workout that leaves you exhausted might feel productive. But if it takes you three days to recover, compromises your long run, or prevents you from completing the rest of your training, we need to question whether it was worth it. The best workouts are the ones that provide the stimulus we're looking for without creating unnecessary fatigue.

2. Not All Speed Work Is the Same

One of the biggest misconceptions about speed work is that every workout is designed to accomplish the same thing. It isn't. There are several different types of workouts we might use during marathon training, and each has a purpose. Tempo workouts help improve your ability to sustain a comfortably hard effort for an extended period. These might include tempo runs or longer intervals at threshold effort. Interval workouts with shorter repetitions under a mile in length can improve aerobic capacity and your ability to sustain faster running. Depending on the workout, these might involve repetitions lasting a few minutes with recovery periods between them. Marathon-pace workouts help you become familiar with the pace and effort you intend to sustain on race day. They also help us evaluate whether your goal pace is realistic. Strides and shorter repetitions can improve coordination, running mechanics, and your comfort running at faster speeds without requiring the same sustained effort as a long interval workout. These workouts aren't interchangeable. And you don't need to do every type of workout every week. When I build a marathon plan, I'm thinking about what the runner needs most at that stage of training. The workouts should complement each other rather than compete for the same recovery resources.

3. Your Current Fitness Determines Your Workout Paces

This is where I see runners get into trouble. They decide they want to run a marathon in 3:30, so they start doing workouts based on a 3:30 marathon pace. Or they look at a training plan online and see a prescribed interval pace that they aren't currently fit enough to sustain comfortably. The goal time becomes the basis for the workout, even when the runner hasn't developed the fitness to support it. I'd rather work backward from your current fitness than ask you to train according to a time you hope to run months from now. If your current fitness supports a particular tempo pace, that's where we'll start. As your fitness improves, we can adjust the workouts. Your goal matters, but your current fitness determines how we train to get there. There's a difference between training at the pace you hope to achieve and training at the pace that produces the right adaptation today. We need to respect that difference.

4. Easy Running Still Does Most of the Work

This is one of the most important things to understand about speed work. Your workouts are important, but they don't replace easy running. Easy running allows you to accumulate aerobic training volume while managing fatigue. It helps develop the foundation that allows you to handle harder sessions and longer runs.

Speed work builds on that foundation. If you're running 35 miles per week, for example, we might include one quality workout and a long run, with the remaining miles performed at an easy effort. Depending on your experience, the structure might look different, but the principle remains the same. You don't need to turn every run into a workout. In fact, if your easy runs are consistently too fast, you may find that your quality sessions become less productive because you're carrying unnecessary fatigue into them. I want your easy running to support your speed work, not compete with it.

5. More Intensity Is Not Automatically Better

This is probably one of the biggest mistakes runners make when trying to get faster. They assume that if one hard workout is good, two must be better. And if two are better, maybe three will produce even more improvement. But training doesn't work that way. Every hard workout creates a training stimulus. It also creates fatigue. The benefit comes from combining that stimulus with enough recovery to adapt. If you add too much intensity, you can end up with a training schedule where you're constantly tired. Your easy runs become harder, your long runs suffer, and your workouts become something you survive rather than execute well.

That doesn't mean you should avoid challenging workouts. It means you should be deliberate about them. For many recreational marathoners, one primary speed or tempo workout per week is a reasonable starting point, alongside a long run. More experienced runners may tolerate additional quality work, particularly when marathon-pace running is introduced into long runs. But there's no universal number that applies to everyone. We have to consider the runner's training history, weekly mileage, recovery, injury history, and the demands of the rest of the plan. The goal is to get the benefits of intensity without allowing intensity to take over the training..

6. Running Fast Is Different From Running Hard

I want to make an important distinction here. Running fast and running hard are not the same thing. You can run relatively fast without creating a tremendous amount of fatigue. Short, relaxed strides are a good example. They're quicker than your normal easy pace, but they're not meant to leave you gasping for air.

On the other hand, you can run at a much slower pace and still be working extremely hard if the effort is beyond your current fitness. This is why I don't want runners judging every workout by the pace on their watch. A tempo workout should generally feel controlled and comfortably hard, not like an all-out race. An interval session may involve a harder effort, but the repetitions should still be appropriate for the purpose of the workout. If the pace requires you to strain, lose your form, or turn the final repetition into an all-out effort, we may be asking too much. The right intensity is determined by the purpose of the workout and your current fitness, not by how impressive the pace looks.

7. Tempo Training Is Especially Valuable for Marathoners

If I had to highlight one category of speed work that is particularly useful for many marathon runners, tempo training would be high on the list. Tempo training helps improve your ability to sustain a strong aerobic effort. It allows you to become more comfortable running at paces that are faster than easy pace but still controlled. A tempo workout might look like this:

• 2 miles easy

• 3 miles at tempo effort

• 1–2 miles easy

Or we might break the work into intervals

• 2 miles easy

• 4 x 1 miles at tempo effort with 90 second jog recovery

• 1–2 miles easy

The exact structure depends on the runner and the training phase. What matters is that the effort remains controlled. You should finish feeling as though you've completed a productive workout, not as though you've raced a 5K. Tempo work can be particularly useful because it develops fitness without requiring every workout to involve extremely fast running. For marathoners, that's valuable. We need to improve your ability to sustain effort while still leaving enough energy to handle the rest of the training week.

8. Marathon-Pace Workouts Have a Different Purpose

Tempo training is important, but marathon-pace work serves a different purpose. These workouts help you become familiar with the effort and rhythm you intend to sustain during the marathon. For example, a workout might look like this:

• 2 miles easy

• 5 miles at goal marathon pace

• 1–2 miles easy

Or, later in a marathon build, we might include marathon-pace segments within a longer run. The purpose isn't simply to prove that you can run your goal pace for five miles. It's to develop familiarity with that effort, practice fueling when appropriate, and evaluate how comfortably you can sustain the pace. Marathon-pace work also provides useful feedback. If your goal pace feels controlled during training, that's encouraging. If it feels like a race effort after only a few miles, we need to consider whether the goal is realistic or whether fatigue is affecting the workout. One workout doesn't determine your marathon potential, but the pattern of how you respond to marathon-specific training can tell us a lot. And remember: goal marathon pace should be based on a realistic assessment of your fitness. We shouldn't force an unrealistic pace simply because it's written into the plan.

9. Intervals Have a Place, but You Don't Need to Race Every Workout

Intervals can be useful in marathon training. They can improve aerobic capacity, help you become more comfortable at faster speeds, and develop your ability to sustain strong efforts. But I don't want you to think that every interval session needs to be extremely difficult. A workout such as 5 x 1,000 meters at an appropriate interval effort, with easy jogging between repetitions, can be productive without requiring you to run every repetition as fast as possible.

The pace should be appropriate for your current fitness and the purpose of the session. If you're constantly trying to run the final repetition faster than the first, you may be turning a controlled workout into a competition with yourself. There's nothing wrong with finishing a workout strongly. But the objective is to complete the prescribed training at the appropriate effort, not to win your own workout. For many recreational marathoners, intervals are one tool among several. They don't need to dominate the plan.

10. Your Speed Work Has to Fit Around Your Long Run

This is where speed work connects directly to our discussion about weekly mileage. Let's say you have a challenging workout on Tuesday and a 17-mile long run on Sunday. If Tuesday's session is so hard that you're still fatigued on Thursday, and your Sunday long run becomes a struggle, we need to look at the entire week.

The problem might be the workout itself. It might be the pace. It might be the recovery between sessions. Or it might be that the total training load is too high. We can't evaluate speed work in isolation. Your workouts, easy runs, long runs, strength training, sleep, and nutrition all need to work together. Sometimes the right adjustment is to reduce the number of repetitions. Sometimes it's to slow the pace. Sometimes it's to move the workout or reduce the intensity of another session. The goal is not to complete the hardest possible workout. The goal is to complete the right workout while preserving the quality of the rest of your training.

11. You Don't Need to Run Fast Every Week to Improve

Another misconception is that progress requires constantly making your workouts harder. You complete 4 miles at tempo effort one week, so the next week you think you need to run 5 miles. Then you run 5 miles, so the following week you want to run faster. But training doesn't need to progress in a straight line. Sometimes we increase the duration of the workout. Sometimes we keep the duration the same and allow the effort to become more comfortable. Sometimes we repeat the same session because consistency is exactly what we need. And sometimes we reduce the workload because the runner is carrying fatigue. There is value in repeating a workout and seeing how it feels several weeks later. If the same session feels more controlled at a similar effort, that can be a sign that your fitness is improving. You don't have to make every workout a new personal record. The goal is to build fitness over time, not to prove that you're faster every Tuesday.

12. What If You're Feeling Great?

This is similar to what we discussed when talking about easy pace and weekly mileage. You have a great workout. Your legs feel fantastic. You finish your intervals feeling strong. So you think, "Maybe I should add two more repetitions." Maybe there's a time and place for that. But most of the time, I would rather you complete the planned workout and finish feeling as though you could have done a little more. That doesn't mean every workout should feel easy. Some sessions are supposed to be challenging. But there's a difference between completing a challenging workout and pushing beyond the intended training stimulus simply because you feel good. Sometimes feeling great is the result of your training working. You don't need to spend that fitness by adding more intensity every time you have a good day. If the current workload is producing good workouts, good recovery, and consistent progress, there's value in staying with it.

13. What If Your Workouts Are Slower Than Everyone Else's?

This is another trap, especially with social media. You see someone posting mile repeats at 6:00 pace. Someone else is running tempo intervals at 7:00 pace. And you're running your own workout at 8:30 pace, wondering if you're doing enough. But you don't know the context. You don't know their current fitness, running history, weekly mileage, recovery, or marathon goals. And you don't know whether the pace they posted was appropriate for the purpose of the workout. Your training isn't a competition with someone else's watch. If 8:30 pace is the appropriate tempo effort for your current fitness, then that's where you should train. Running faster simply because someone else does won't necessarily produce better results. In fact, if you turn every workout into an effort that's too hard for you, you may compromise the consistency that allows you to improve. Your job is to execute the right workout for you.

14. Use Your Workouts as Information

One of the best ways to evaluate speed work is to look at how you respond to it over time. Imagine a runner who completes a tempo workout of 3 x 1 mile at a controlled effort. A few weeks later, the same runner repeats the session and finds that the pace feels more comfortable. That's useful information. Maybe the runner has improved fitness. Maybe recovery has improved. Maybe the original workout was simply better matched to their abilities this time. We shouldn't draw sweeping conclusions from one session, but repeated workouts can help us understand whether the training is working. I want to look at more than the pace on the watch. How did the workout feel? Were the repetitions consistent? How was your recovery? Were you able to complete your next easy run and long run as planned? Those details help us decide whether to maintain the workload, progress it, or make an adjustment. Your training history becomes evidence. We don't have to guess as much when we pay attention to how you respond.

15. Speed Work Should Serve Your Marathon Goal

This is ultimately how I want runners to think about speed work. Don't ask, "How fast can I run this workout?" Ask, "What does this workout need to accomplish?"

If your goal is to finish your first marathon healthy and strong, you may need a different approach from an experienced runner trying to set a personal best. If you're building an aerobic foundation, your training might emphasize consistency and controlled threshold work. As you get closer to race day, we may introduce more marathon-specific sessions. If you're already running substantial mileage and recovering well, we may have room for more demanding workouts. The right approach depends on the runner and the goal. Speed work is a tool. It's not the goal. The goal is to develop the fitness, endurance, and efficiency required to run your best marathon.

16. The Bigger Picture

This brings us back to the philosophy we've been building throughout this series. Easy running gives us aerobic development without unnecessary fatigue. Weekly mileage allows us to accumulate training volume. Long runs develop endurance and durability. Speed work helps improve the ability to sustain stronger efforts. Marathon-pace training prepares us for the specific demands of race day. And recovery allows us to adapt to all of it. None of these things exists independently.

You can have a great interval workout and still have a poor training week if you can't recover from it. You can run a fast tempo and still struggle in the marathon if your long runs and aerobic development aren't sufficient. And you can become a much better marathoner without running every workout at the fastest pace possible. The goal is to put together the right combination of training stress and recovery. That's why I don't want runners chasing speed work for the sake of speed work. I want them to understand what each session is designed to accomplish, execute it at the appropriate effort, and recover well enough to continue training consistently. Because ultimately, marathon fitness isn't built by one incredible interval session. It's built by stacking good training weeks together. And that's how you become a better marathoner.