The 3 Biggest Speed Work Mistakes

Is Your Speed Work Making You Slower?

 

While this subtitle may give off click-bait vibes, it’s actually a common problem among individuals preparing for various selections, races and time trials. My hope is that after reading the article, you’ll be equipped with the tools necessary to utilize speed work as it’s intended: to get faster at a mid to long distance endurance run.

I pride myself on programming with rigorous attention to detail and using the individual’s current abilities to guide pacing, intensity and volume prescriptions. However, there’s a distinct difference in results between individuals who stick to the prescribed paces and those who don’t.

Speed work isn’t overly complex, but it’s also not as straightforward as many people tend to believe. On the programming side, it requires specific instructions that, when adhered to, produce excellent results. On the execution side, it requires practice to develop the skill of pacing and discipline to stick to the prescriptions.

This article will discuss the intricacies and efficacies of speed work (intervals/repeats), as well as the top 3 mistakes most trainees make when conducting these training sessions. In part 2, I’ll discuss tempo work, which is another area of struggle for runners at various levels of proficiency. Let’s start by defining speed work.

 

Speed Work; Repeats > Intervals

Speed work is the lynchpin of a running speed development program. In the context of endurance running, speed work is often referred to as repeats or intervals. As I do in my coaching program, I’ll refer to them only as repeats throughout this article. Although there’s nothing wrong with calling them intervals, there’s a very specific reason for this distinction: ‘repeats’ indicate that paces should be REPEAT-able.

Intervals can absolutely be run at repeated paces, but I’ve found that referring to them as repeats helps solidify the point that each work period should be done with ‘repetition’ in mind. In other words, whether you’re doing 200 meter repeats, 400s, or miles, you should be aiming to run consistent paces within a small pacing range. Thinking of them as repeats rather than intervals can help a less experienced runner conceptualize the goal and ensure they’re putting appropriate effort into each one.

Speed work is the most effective way to move the needle from where you’re at now to where you want to be in the future. If you’re reading this, chances are you want to improve your running speed, and speed work (repeats) will be the main strategy in doing so. By running repeats consistently with the right volume, paces, rest periods and intent, you’ll watch your run times get faster and faster. 

A repeat session combines mainly the aerobic and glycolytic energy systems, and allows runners to improve their ability to maintain faster paces for longer periods. The main adaptations derived from speed work include increasing your VO2 max, and—more importantly—raising your lactate threshold. Running skill development is another crucial component of speed work, which will in turn improve your running economy. These three adaptations—VO2 max, lactate threshold and running economy—comprise the entire formula for running success. Now that we’ve attained a clear cut understanding of speed work and its intended adaptations, let’s take a look at the first mistake; running too fast.

 

# 1 - Repeats Too fast

It’s crucial to delineate the difference between speed work in a distance running sense versus speed work in a top-speed development sense. Repeats are NOT the same as sprints. Speed work for a runner aiming to improve their 5-mile time should look and feel drastically different from that of a sprinter developing their 100-meter sprinting speed.

‘Sprinter’ Speed Work

Sprinting is fueled by the ATP-PC energy system, responsible for short bursts of speed and power. As such, sprinters focus on maximal intensity efforts, running at full speed with long rest periods to ensure complete recovery between reps. This allows them to maintain top-end speed, which is their intended adaptation. Often, they will cut the workout as soon as sprint speed drops off. For example, a 100-meter sprinter may do 5-6 reps at max effort with 10+ minutes of rest between each round, as fatigue is the enemy of speed and power development.

If the sprinter slows on lap 3, for instance, a high-level coach may suggest discontinuing the session to avoid interference with max-speed adaptations. There are two key reasons for this: first, running slightly slower than usual yields adaptations to running slower, which is not ideal for a sprinter. Second, it can indicate that the athlete is not fully recovered and/or prepared for the session, and continuing will further impede recovery.

‘Endurance Runner’ Speed Work

In contrast, distance runners perform submaximal effort repeats, focusing on maintaining a fast—but sustainable—pace with shorter rest intervals. Their goal is to improve endurance and the ability to hold a faster pace for longer durations, rather than achieving peak speed in a single burst. While both types of athletes perform speed work, the intensity and recovery structure are adapted to suit the differing physiological demands and energy system requirements of sprinting versus distance running.

For endurance-focused speed work, while cutting the session short isn’t out of the question, the adaptations are less sensitive to small drops in performance. The goal for repeats aimed at endurance development is to adapt to a realistic pace that’s slightly faster than the runner's current ability, with incomplete rest between efforts.

As such, your repeats should NOT be sprints. They should occur at reasonable, realistic paces based on your current ability or goal pace. When repeats are performed too hard, even if they are repeatable in the short term, the fatigue and recovery debt accrued often prove unsustainable, especially considering the additional training in a block. In other words, although you may complete the session, how will the excess fatigue affect your performance, recovery, and injury susceptibility in the following days or weeks?

For example, many run programs containing repeats suggest running them at ‘goal pace’. In some cases, this can be excellent. If, for example, you’re running a 12:00 2 mile and your goal is to run an 11:45 2 mile, you’ll likely see great, sustainable results running certain repeats at your goal pace.

But if you’re running a 15:00 2 mile and you have a lofty goal of running a 12:00 2 mile, while this isn’t too far-fetched to ever achieve, running your repeats at goal pace is wildly unrealistic, even if you’re able to grind your way through them and hit the prescribed paces. It’s very unlikely you’ll be able to sustain and improve upon them in subsequent sessions due to the extreme fatigue cost of such high relative effort.

In such cases, it’s more appropriate to use your current pace for determining your repeat paces. There are a multitude of running pace calculators available on the internet, but here’s a quick cheat-sheet for repeats of various distances for a runner looking to improve their 2 and 5 mile times.

Current Vs. Goal Paces (using hypothetical round #s for simplicity)

• Current 5 mile: 35:00 or 7:00/mi

• Goal 5 mile 23:30 or 6:30/mi

• Current 2 mile: 13:00 or 6:30/mi

• Goal 2 mile: 12:00 or 6:00/mi

First off, while still difficult to achieve these run improvements in one training block, it would be realistic to achieve them over 12-16 weeks of deliberate training (not just with repeats, but other running as well).

Repeat pacing guidelines for shorter repeats geared towards 2 mile improvement: 

• 200s - workout 1: 16x200m repeats at 15-20 sec/mi faster than current 2 mile pace (6:10-6:15/mi or ~45-47 sec/200) w/ 1:1 work:rest

• 400s - workout 1: 8x400m repeats at 10-15 sec/mi faster than current 2 mile pace (6:15-6:20 or 1:33-1:35/400) w/ 1:1 work:rest

• 800s - workout 1: 4x800m repeats at 5-8 sec/mi faster than current 2 mile pace (6:22-6:25 or ~3:09-3:12/800) w/ 1:1 work:rest

*Subsequent workouts (progression):

• Add volume (1-2x200s, 1x400, 1x800 every 2 sessions) 

• Reduce rest times (1:.9, 1:.75 etc)

• Match/increase pace by 1-2 sec/lap (200s), 2-3 (400s), 3-4 (800s)

(sometimes these progressions can overlap but it’s best to focus on one per session, especially early on in a training block)

As you can see, the paces for each individual distance is different—as it should be—thus allowing the runner to adapt to paces slightly faster than they’re currently able to run 2 miles. Over time, the volume and speed increases slightly, and/or rest periods decrease as fitness improves. This approach is far more sustainable than either a) doing everything at your goal pace or b) treating each repeat as a full on sprint. It’ll also help you avoid the next common mistake; non-repeatable repeats.

 

# 2 - Repeats Not Repeatable

Dovetailing off of the previous mistake of going too hard, a great litmus tests for newer runners is to identify whether their repeats were actually repeats, or if they were just ‘hard’, or ‘fatiguing’ efforts. Again, I refer to them as repeats instead of intervals for a specific reason: they should be repeatable. Although few people are skilled enough at pacing to make every single repeat exactly the same, that should be the goal. The longer the repeat, the more of a pace range is acceptable, but even so, there shouldn’t be massive pace discrepancies between rounds. Commonly, I’ll see a repeat session that looks like:

Runner’s current 2 mile: 16:00

Runner’s goal 2 mile: 12:00

Workout: 8x400m repeats @ goal pace (6:00/mi aka ~1:30/400m), 1:1 work:rest

Lap 1: 1:28

Lap 2: 1:32

Lap 3: 1:36

Lap 4: 1:39

Lap 5: 1:49

Lap 6: 1:48

Lap 7: 1:59

Lap 8: 2:03

It should be obvious that there’s nothing ‘repeat’ about this session. As is common amongst less experienced runners, he started out way too fast on the first few, and due to the inherent fatigue, wasn’t able to continue with the repeated effort. His last repeat was a full 35 seconds slower than his first one. Adaptations from this session are virtually non-existent, because he was running too fast at the beginning and too slow (due to fatigue) at the end. The recovery cost for a session like this is also very high. The overall result? Lots of fatigue. Little adaptation. 

If we refer back to the previous point’s examples of pacing, we can reconstruct a workout plan for this runner that’ll actually move the needle in his running speed, without the extreme recovery demands. (Repeats are still a high-fatigue endeavor, but less so when executed correctly.)

Since this runner’s goal 2 mile pace is 2:00/mi faster than his current 2 mile pace (6:00 miles vs. 8:00 miles), it would be more reasonable to program based on current pace. We’d simply subtract 10-15 seconds per mile off his current pace (8:00/mile) and aim to run the 400s at that pace. It would look like:

400m repeats @ 10-15 sec/mi faster than current 2 mi pace (16:00 2 mile = 8:00/mi), 1:1 work:rest

Every lap, the runner should shoot for a 1:54-1:57 (1 sec buffer on each side). This would be a far more sustainable and REPEATABLE pace. 

A common rebuttal from athletes is that this session would be ‘pretty easy’. But let’s recall that this is simply your repeat pace for day 1, week 1 of a program or training block. Your repeats shouldn’t be a ‘barely got it done’ experience every single week. That’s unsustainable. As you continue to progress by adding speed, volume, and reducing rest periods, these sessions would continue to prove more difficult. 

For example, 6 weeks from now, this runner may be running 12x400s w/ 1:15 rest at 1:44-1:47. And how about 3 months from now? 6 Months from now?

Running is a long game. No single workout is make or break. It’s the ability to execute them again and again and make continuous, subtle improvements. However, it’s crucial that I define ‘again and again’, because some people take this too far and run repeats too frequently.

 

#3 - Repeats Are Too frequent

Repeats—even when executed with precision—are a high-fatigue training session. They result in not only physiological fatigue, but also a higher degree of psychological fatigue compared to many other forms of training. 

As such, they must be programmed carefully and not overused. In general, doing a classic repeat workout more than once per week is, at best, only appropriate for very short periods of time. At worst, it’s simply too much for most runners, especially in the context of a tactical athlete for whom running is just part of their overall fitness equation. If you’re running repeats 2x/week, you better have a good reason for it. 3x a week? I don’t know many people who can sustain that, and even if they could, they’d likely be better off cutting back and focusing on quality more so than quantity. 

For most people, running repeats 1x/week—sometimes even every 10 days or biweekly—is typically the best option, at least to start out. When done too frequently, you increase the risk of overtraining, injury, or stagnation of progress, all of which result in frustration. Additionally, even if you are running them at a frequency that works for you, you’ll also want to consider having ‘non-speed weeks’ during which you take some time off from running, or at least from running fast.

There are multiple bodily systems in which fatigue accumulates from higher intensity sessions like this, and allowing them to recover adequately will keep you progressing at a faster rate, even if that means taking a ‘down week’ or deload. For some general rules of thumb—not concrete rules, but general guidelines—I recommend the following:

• Do consistent speed work for 12-16 weeks at a time, then take a few weeks to a month off from it. During this off time, you can run hills, strides and pickups/surges, but refrain from true speed work.

• Do 1 speed work session/week, ideally after a rest day or easy training day. If you want to run fast another day, tempo work, fartlek runs, hills, strides or cruise intervals can be great.

• If you’re struggling to recover/progress, consider dropping to 1 speed session every 10-14 days.

• If you’re doing weekly speed sessions throughout this time, take a ‘non-speed week’ every 3-6 weeks, even if you’re recovering and progressing well

• Consistently check in with yourself with the following questions:

1. How are my joints/connective tissue/bones feeling?

2. Am I making progress with my repeat sessions (running faster, more volume, reduced rest or combo)?

3. Am I making progress with my other runs throughout the week?

4. Am I making progress in my non-running training?

5. How do I feel in regards to overall fatigue, both physically and mentally? (am I dragging ass through the day, noticing changes in appetite, feeling smoked ½ way through sessions, not sleeping well, unable to focus, very unmotivated to train, etc?)

Being mindful of these questions—not just for speed work or running, but all training—is a critical aspect of managing your training load and recovery, as well as ensuring what you’re doing is actually bringing you closer to your goals. 

Remember, we don’t get faster from simply training more. We don’t improve from crushing this week’s repeat session even though it was a ‘smoker’.

We get faster from recovering from more training. We get faster from stringing together week after week of high quality, yet sustainable, workouts.

Therefore, learning how to assess yourself as you go is crucial when it comes to prolonged speed improvements and training progress in general. 

 

In Closing

Now that you’re aware of the 3 most common speed work mistakes, the rest of it is up to you. Do you take this advice and put it into action, or do you bury deep down in your bank of ‘things that are good to know, but don’t apply to me’? If you opt for the former, you can expect long term sustainable progress and a lower risk of injury. Whereas, opting for the latter leaves more variables to chance, and often results in disappointment. 

Speed work is the foundation of endurance running improvement, but only when executed correctly. Once you’re equipped with the knowledge, it’s time to go to work on fighting your ego’s tendency to push for a ‘bit more’ or a ‘tad faster’. Pacing is a skill. Sticking to the pace is a game of discipline. Develop the skill by conscious practice and repetition. Develop the discipline by exercising it in your training and elsewhere.

Thank you for reading part 1. Part 2 will discuss the top 3 most common mistakes when it comes to tempo work. Let me know in the comments which of these mistakes speaks to you most!