Part 2: Tempo Work Mistakes
Is Your Tempo Work Also Making You Slower?
In part 1, I discussed the three biggest mistakes runners make when approaching speed work, also known as intervals or repeats. While properly executed repeats are crucial in your quest to get faster, they’re not the definitive answer. To truly maximize your speed development in mid to long distance running, tempo work must enter the scene. But like repeats, tempo runs are often executed in a way that leaves runners scratching their heads, wondering why they’re putting in so much hard work but not seeing consistent speed progressions.
This article will discuss all things tempo work, as well as highlight the three most common mistakes I see in my coaching program when it comes to tempo work execution. Like speed work, tempo work isn’t overly complex, but it’s not as cut and dry as many people think.
There’s also more ambiguity around tempo work, because it can be run at different efforts depending on the runner’s goals. Tempo runs are commonly used interchangeably with threshold runs, and while a run coach may program tempo work to be done at threshold pace, a classic tempo run is actually run slower than threshold pace.
Let’s briefly touch on what threshold means and why it may not be appropriate for your tempo runs. An athlete's lactate threshold is the point at which blood lactate surpasses 4 mmol/l. This occurs when lactate accumulates due to glycolysis (burning carbs for fuel), leading to excessive blood acidity from hydrogen ion accumulation.
This acidity—what many incorrectly refer to as lactic acid—results in extreme fatigue and discomfort, causing the runner to involuntarily slow their pace. If you’ve ever run a middle-distance race or time trial where you were holding a certain pace for a portion of it, only to see your pace drop off significantly towards the back end (or even earlier) due to fatigue, you’ve experienced crossing your lactate threshold.
In a longer race or timed event, staying right at or below your lactate threshold is advised because you’ll actually be able to sustain the pace for the duration of the run. Most well-trained but non-elite runners can generally run at lactate threshold for 45-60 minutes. This is known as ‘sustainable threshold’.
After crossing your lactate threshold, your time horizon shortens significantly. While lactate itself is a fuel source, the real issue is the accumulation of hydrogen ions (H+) that accompany increased lactate production. These hydrogen ions cause the muscular environment to become more acidic, interfering with muscle contraction and leading to a rapid onset of fatigue.
In this state, you may be able to sustain the pace for only 3-5 minutes before performance degrades significantly. As such, the goal of tempo work is to slowly and incrementally increase your lactate threshold, and this is best achieved by sustaining a pace just below it.
Now that we’re clear on the basics of tempo work, let’s take a look at some of the mistakes that could be holding you back.
Too Fast
The first mistake is, hands down, the most common, and one I’m constantly emphasizing with my clients. While many less experienced runners find this fact counterintuitive, running tempos too fast won’t make you faster. The prirmay reason for this is the fatigue cost of overexertion on tempo runs, which makes continuous progression unsustainable. Many people aim to run their tempo runs at one of two paces:
Their time trial or race pace (at or past threshold pace)
Faster than last week (when mistake ‘a’ was made last week)
Why is this unsustainable? Let’s use a gym analogy to explain why running all tempo runs at threshold pace may not lead to the best results. Lifters who aim to maximize strength often make the mistake of training with weights too close to their 1RM (one-rep max) on a regular basis. While maxing out and continuously chasing PRs may make you stronger for a short time, it quickly leads to recovery issues due to excessive fatigue. On the other hand, training with more manageable loads—usually in the range of 75-90% of your 1RM—allows you to build strength without overtaxing your body.
Similarly, on tempo runs, working slightly below your lactate threshold allows for better long-term progress without the excessive fatigue that inherently accompanies constantly pushing to the limit. Again, while some runners may be able to manage it for a few weeks or even a month, eventually, the excessive, cumulative fatigue on the musculoskeletal system, nervous system, joints, connective tissue, and the runner’s psychology surpass their ability to adapt.
As such, you’ll want to be more calculated with your tempo pace. If you don’t know where to start, a great rule of thumb is the following (assuming the runner has built a base):
Run a ~4-6 mile time trial and calculate your per-mile pace.
For this example, we’ll use a 5 mile: Hypothetical time - 37:30 or 7:30/mi
For your first tempo run, aim for a duration of ~40% of your 5 mile time
40% of 37:30 is exactly 15 minutes
Calculate a pace 15-20 seconds/mile slower than your 5 mile split (7:30/mi) = 7:45-7:50/mi
This is your target tempo pace; your first tempo run will be 15 minutes at 7:45-7:50
This will likely feel easier than you’d expect it to, because you’re running SLOWER than your 5 mile pace and a 60% shorter duration. This is FINE, and exactly how it should feel. Progression may look like:
Week 1: 15:00 @ 7:45-7:50 pace (hypothetical result: 7:47/mi RPE6.5-7)
Week 2: 17:00 @ 7:45-7:50 pace (hypothetical result: 7:46/mi RPE6.5-7)
Week 3: 20:00 @ 7:45-7:50 pace (hypothetical result: 7:48/mi RPE 7)
Week 4: 22:00 @ 7:45-7:50 pace (hypothetical result: 7:46/mi RPE 7)
Week 5: 22:00 @ 7:40-7:45 pace (hypothetical result: 7:42/mi RPE 7.5)
Week 6: 24:00 @ 7:40-7:45 pace (hypothetical result: 7:40/mi RPE 8* - last tempo before deload at RPE 8 is perfectly acceptable!)
Week 7: deload - no tempo (easy run w/ strides or pickups, or a non impact substitution)
Week 7: 26:00 @ 7:35-7:40 pace (hypothetical result: 7:37/mi RPE 7)
Week 8: 28:00 @ 7:35-7:40 pace (hypothetical result: 7:36/mi RPE 7.5)
Week 9: 30:00 @ 7:30-7:35 pace (hypothetical result: 7:31/mi RPE 7.5)
Week 10: re-test 5 mile (hypothetical result: 36:10 or 7:14/mi)
Result: 15 seconds off per-mile split, no injuries, consistent improvement.
This is an example of a textbook tempo run progression. That said, because It’s a hypothetical scenario and most runners won’t be able to execute 10 weeks of tempo runs with such consistency, your progression will likely look a bit different. This is totally fine, but having a clear understanding of ‘optimal’ will help guide your programming and execution.
Let’s take a look at what your tempo work may look like if you run it too hard.
Week 1: 15:00 @ 7:45-7:50 pace (hypothetical result: 7:29/mi RPE 8)
Week 2: 17:00 @ 7:30-7:35 pace (hypothetical result: 7:34/mi RPE 7.5)
Week 3: 20:00 @ 7:30-7:35 pace (hypothetical result: 7:33/mi RPE 8)
Week 4: 22:00 @ 7:25-7:30 pace (hypothetical result: 7:32/mi - RPE 8.5 aka too high)
Week 5: 22:00 @ 7:25-7:30 pace (hypothetical result: 7:28/mi - RPE 9 aka too high)
Week 6: 24:00 @ 7:20-7:25 pace (hypothetical result: 7:33/mi - RPE 9.5 aka way too high - runner should not have increased pace after last week’s RPE 9)
Week 7: 26:00 @ 7:15-7:20 pace (hypothetical result: 7:31/mi RPE 9 - signs of stagnation and excess fatigue - runner should deload)
Week 8 (deloads? Never heard of her): 28:00 @ 7:15-7:20 pace(hypothetical result: 7:48/mi RPE 9.5 - runner is overreached and slowing down because of their unsustainable progressions)
Week 9: 30:00 @ 7:10-7:15 pace (hypothetical result: 7:50/mi RPE 9.7 - runner stubbornly continues to decrease pace range and increase duration, despite falling behind)
Week 10: re-test 5 mile (hypothetical result: 37:52 or 7:34/mi)
Result: All that work ended up producing a SLOWER performance by 4 seconds, extreme fatigue, potential nagging knee/lower leg pain, lots of frustration.
Is the runner actually slower? Maybe, or maybe not. But because this runner started too fast in week 1 and stubbornly continued to decrease the pace range while also increasing the duration, progressions weren’t sustainable due to excessive fatigue. Most of the runs were RPE 9+, which is far too high for tempo work. The week 10 re-test example was also generous, and solely based on tempo progression mistakes. If, like many, this runner also made speed work mistakes highlighted in part 1 and ran his easy runs too hard, he’d have likely put up an even slower time in the re-test. As you can see, these mistakes are rather subtle and won’t be apparent unless you’re highly calculated and honest with yourself or your coach. Now that you’re clear on the potential cost of running too hard, let’s take a look at the next common mistake: finishing too strong.
Strong Finish?
An effective tempo run should be conducted at a rhythmic, sustainable pace with minimal fluctuations. Ideally, doing tempo work on mostly flat surfaces is best, unless you’re training for an event that’ll take place in hilly terrain. In this case, you should still run some of your tempos on flat or slight rolling hills, but an occasional hilly tempo (every 3-4 weeks) would be warranted to get accustomed to uphill and downhill running. But regardless, a common mistake with tempo work is to execute most of the run perfectly, only to turn on the jets at the end to ‘finish strong’ as if you’re racing. Let’s take a look at an example using a 24:00 tempo run broken down into four, six minute splits:
Min 0-6: 7:24/mi (RPE 6)
Min 7-12: 7:25/mi (RPE 7)
Min 13-18: 7:23/mi (RPE 7.5)
Min 19-24: 6:55/mi (RPE 8.5-9)
This runner stuck to the game plan in the first ¾ of the tempo run, but then the ego took over for the last split and while it didn’t completely ruin the workout, it would absolutely result in more fatigue than a more disciplined finish. Doing this once wouldn’t be the end of the world, but this is rarely a one-off occurrence because it feels good (for the ego) to finish strong. We’ve also been led to believe that ‘finishing strong’ is always a good thing, as it shows how tough and dedicated we are. But unfortunately, there are no free lunches in running (or fitness in general). When done consistently, the pursuit of the strong finish will backfire; that prideful finishing push at a ~9 RPE will inevitably result in needless, excessive fatigue and therefore lower potential for adaptation. Whent running tempo runs, a sublte negative split is an excellent habit, but finishing at a realistic tempo pace is still paramount. I can’t stress this enough. Here’s what a solid split would look like using the same run:
Min 0-6: 7:25/mi (RPE 6)
Min 7-12: 7:24/mi (RPE 7)
Min 13-18: 7:24/mi (RPE 7.5)
Min 19-24: 7:21/mi (RPE 7.5-8)
This is about as textbook as a tempo run gets, and while it doesn’t need to be this precise (especially if you’re less seasoned), it again allows you to see what optimal looks like so you can start to piece it together. You may notice that the RPE increases each split, and be wondering why. Glad you asked! That’s the final mistake we’ll discuss: RPE blunders.
RPE Too High
The rate of perceived exertion (RPE) of a tempo run should be approximately 7.5, occasionally 8. I emphasize to my clients that in the context of a hybrid training plan in particular, RPE is more important than hitting a perfect pace range week to week. Your running preparedness will fluctuate day to day, week to week due to fatigue from other training, stress, sleep, nutrition, hydration, weather, and other factors. While it’s common practice to throw RPE out the window and just shoot for a specific pace (‘faster than last time or bust’), let’s assume you’re dedicated to the plan and are willing to abide by the above ‘RPE > pace’ guidelines. Where many go wrong in this regard is that they try to achieve this RPE too early on in the run, then sustain it for the duration.
For example, let’s look at a 30 minute tempo run at RPE 7.5. If you’re 3 minutes into the run and it’s already feeling like an RPE 7.5, what do you think the RPE will be 10 minutes in? 18 minutes in? 25 minutes in? In most cases, if you continue to sustain your RPE 7.5 pace from 3:00 into the run, there’s absolutely no chance that pace will still be a 7.5 RPE in later portions of the run. Let’s take a look at a 30:00 tempo run done right (split into five, six minute splits):
Run prescription: 30:00 tempo run @ RPE 7.5 or 7:20-7:30 pace (favor RPE > pace)
Min 0-6: 7:25/mi (RPE 6)
Min 7-12: 7:24/mi (RPE 7)
Min 13-18: 7:24/mi (RPE 7.5)
Min 19-24: 7:24/mi (RPE 7.5)
Min 25-30: 7:22/mi (RPE 8)
This is a realistic depiction of what an RPE progressions should look like throughout a run. During the first 12 minutes or so, the runner is less hampered by fatigue, and therefore the RPE at their goal pace is lower. Later in the run as fatigue accumulates, RPE will inherently increase, but NOT because the runner is running harder or faster.
Why, then? Because when you sustain a tempo pace for longer and longer, fatigue occurs as a byproduct which inherently raises the perceived effort. So while the entire run wasn’t a 7.5 RPE, the AVERAGE RPE was a ~7.5. (RPE is always subjective and never perfect, but it’s still critical to learn and be honest with.) The result? The adaptation-to-fatigue ratio for this run was realistic and sustainable, allowing for better recovery and room to improve in next week’s tempo session (and the week after, and so on). However, let’s use the exact same runner and the exact same prescription, but today, the runner will be shooting for RPE 7.5 from the get-go and since it says ‘RPE>pace’, will not be as calculated with their pacing.
Run prescription: 30:00 tempo run @ RPE 7.5 or 7:20-7:30 pace (favor RPE>pace)
Min 0-6: 7:04/mi (RPE 7.5)
Min 7-12: 7:11/mi (RPE 7.5)
Min 13-18: 7:24/mi (RPE 8)
Min 19-24: 7:29/mi (RPE 8.5)
Min 25-30: 7:21/mi (RPE 9)
The mistake the runner made was subtle, but would prove costly if done regularly. He aimed to hit a 7.5 RPE from the get-go, and maintain it throughout the entire run. Since he’s going into the run fresh, an RPE 7.5 in the first 6 minutes will inevitably be faster than the prescribed pace range. But since the run is 30 minutes long, sustaining this pace at this RPE won’t be realistic due to natural fatigue accumulation.
The result? While the average pace of the run was slightly faster (7:23/mi in example 1, 7:17/mi in example 2), the RPE was likely in the 8.5 range, which is too high for sustainable weekly tempo work. This runner will pay largely the same price as runners making mistakes 1 & 2: high fatigue, lower stimulus, stagnation, regression or injury.
Using another lifting analogy, think of hitting a 5 RM back squat. Since you’re hitting a true 5RM, the RPE of the set will ideally be very close to 10. But will rep 1 be a 10? How about rep 2 or 3? You can’t go any higher than 10, or else you’ll fail. So by default, the RPE of each rep will be different, likely ascending from 6-7 all the way up to 10. The same concept applies to tempo runs. The take home for this is that like any other fitness discipline, your RPE will ascend as the training progresses and fatigue accumulates. Trying to manually maintain an exact, constant RPE throughout the session will lead you astray. Discipline, repetition and pushing aside your ego are key skills to develop when it comes to managing your intensity.
In Closing
Well-executed tempo work can be transformative for mid to long-distance runners, but only if approached with patience, precision, and without ego. Running your tempos too fast, pushing to ‘finish strong,’ or ignoring the nuances of RPE can all lead to stagnation, regression or even injury. The most effective way to improve your lactate threshold and overall speed is by staying disciplined and adhering to manageable pacing and effort prescriptions. When tempo work is executed with consistency and respect for your body’s limits, it becomes a powerful tool in your training arsenal that yields lasting improvements without compromising recovery. Remember, small, calculated gains will always beat reckless intensity over time.
Learned a lot from this, thanks