Mistake #1: Running Too Fast On Easy Days

I’m reminded of a comment made by the Australian distance runner, Ed Goddard, who, when appearing on an Inside Running Podcast bonus show, said something to the effect: ‘It doesn’t matter if you run 40 minutes for 10k or you’re an elite, easy pace is 4:30/km’ (1). Ed was rather sarcastically observing the tendency for recreational runners to run well above an easy intensity for general mileage runs. If you’ve been running long enough, you know how common this is; we laugh about it and I’m sure everyone’s Strava feed is full of evidence to this fact. Perhaps it’s the source of good-natured banter in your training group, where one runner’s always ‘half-stepping’ or there’s another who’s convinced anything slower than 5:00/km provides ‘no aerobic benefit’. It’s funny because it’s silly, and yet people still do believe these ideas and behave in this way to the point of compulsion, which can be quite tragic when it becomes detrimental to performance. Runners devote hundreds of hours every year to training, and if that training isn’t effective, then all of their hard work produces little more than frustration, if not injury or illness.

So, I’ve chosen to begin here, because I believe ‘running too fast on easy days’ is the most common cause of a dysfunctional training regime.

However, it’s no surprise that this is such a widespread occurrence. The running world is rife with conflicting ideas on this topic, which ultimately leads to confusion. Very few authorities prescribe a methodical approach to easy running that’s based on data. There’s plenty of vague advice, such as to run at a “conversational pace” or stick to “Zone 2”. This is all well and good for a new runner, for whom simply running more will yield rapid improvement. But as we develop, our training zones become more distinct, and improvements become more difficult to eke out. Therefore, we need to be more deliberate and precise with our training intensities. You can open any book on training and read endless prescriptions for VO2 max intervals, threshold runs, tempos, hill repeats, progressive long runs, etc., but very few offer any precision around easy paces or intensities, and the advice that is offered, doesn’t seem to line up with what the best runners in the world are doing. Despite easy running making up the majority of one’s training, it seems to be an afterthought. This allows people to:

1) undervalue easy running

2) remain ignorant of the physiological benefits of easy running (if done correctly)

3) develop bad habits early that they never seem to shake

In this article, I intend to explain the physiology of easy running and why running much easier between hard sessions is a more effective training approach. I’ll also analyse the training of elite runners and use this as the basis to prescribe easy paces for non-elites.

But first, let’s look at how training works.

Running, for the most part, is a simple sport. You stress the body, recover, then repeat again and again. Some runners may have never learned this pattern, while others suffer an amnesia of sorts and begin to think that they exist outside of the rules of physiology. Whether it’s through a misguided ‘no pain, no gain’ mentality, the belief that faster is always better, an egotism born of insecurity - or just plain stubbornness, many runners will resist the need to slow down on easy days - so that they can actually recover. Instead, they’ll continually push the pace, so that every day between hard workouts becomes a moderate workout in itself.

If you asked a weightlifter to follow a similar schedule; to work the same muscle groups every day, hard one day, moderate the next and so on, you’d be met with a quizzical look. He/she would immediately recognize that this is not a winning strategy, because it doesn’t conform to a pattern of stress and recovery. The weightlifter would know that the stress of a hard workout will break down the muscle fibres and then require a period of regeneration, during which time the fibres will heal – and ideally be a little stronger than they were prior to the stress. This process is called supercompensation (2).

Now, you might be thinking that this is a false equivalency, ‘running and weightlifting aren’t the same’, and in many ways they aren’t. However, if we wish to improve in either sport, we must adhere to the principle of supercompensation. After a stress, our bodies require a recovery period in order to adapt in a positive direction. This period of regeneration will vary depending on the severity of the stress and the powers of recovery possessed by the individual, but as The American College of Sports Medicine states, “at least 48 hours should be allowed between higher intensity exercise of the same muscle groups” (3).

 The graph above (Moffatt, 2019) illustrates the cycle of supercompensation. Ideally, we would introduce another intense stress at the height of the supercompensation period, when our performance is at its peak. The cycle would begin again, but this time from a higher starting point. If we were to re-stress the body while still in the recovery phase, we would start the cycle from a lower point than our baseline (and regress). If we continually re-stress our body while in the recovery phase, our performance will trend downward over time. This is regarded as overtraining and is depicted below.

Supercompensation (4)

The green lines above depict an effective pattern of stress and recovery. In this instance, the performance trends up over time. The red lines demonstrate a dysfunctional pattern; where the body is continually stressed while still in the recovery phase, and so the performance trends down. These are two extreme examples. It’s possible (and likely more common) for overtraining to manifest as a slight decrease and then stagnation of performance, rather than a downward trend.

Note: supercompensation is often confused for “crash training”, but this is a misinterpretation. All training that introduces a higher stress to the body, in order to provoke physiological adaptation, is attempting to utiliise supercompensation.

Beyond the need for muscular recovery, when performing intense exercise, many hormones are released into the bloodstream, including Cortisol. According to the exercise physiologist, Alexandra Rose, Cortisol breaks down fats and carbohydrates providing “a rise in blood sugar for immediate energy” (5). It also activates the sympathetic nervous system which generates a fight or flight response.  By doing so, Cortisol may allow us to train at higher intensities, but if done too frequently and without adequate recovery, Cortisol can constantly ‘float’ in the bloodstream, which can cause an array of negative consequences. Among them:

·      chronic fatigue

·      muscle fatigue or a noticeable decrease in power while exercising

·      sleeplessness

·      suppressed immune system resulting in consistent illness

Therefore, the need to slow down on easy runs is all the more important, as even moderate intensity efforts can raise Cortisol levels, and too frequent a Cortisol response may prevent our bodies from eliciting a training effect altogether. As Mullner writes, excessive amounts of Cortisol in the bloodstream “can interfere with the body’s attempts to recover and adapt to the exercise stimulus” (6). This can place a runner into a catabolic state, wherein their body breaks down muscle, when it should be repairing those muscles.

So, what is an easy run?

An easy run, commonly referred to as a “general mileage run” or “recovery jog” is a type of run that we can perform while still in the recovery phase between hard workouts. Easy runs make up the “base” or “foundation” of an effective training program, and allow us to accumulate more training volume, which is among the ‘greatest predictors of long-distance running performance’ (7). By increasing our training volume, we acquire more running-specific adaptations, including:

·      Greater mitochondrial density: mitochondria are responsible for energy production in the muscle cell. In the presence of oxygen, they break down fats, carbohydrates and proteins, giving our muscles the energy to contract. Mitochondria also oxidize lactate, which can reduce the amount of lactate entering the bloodstream during moderate to hard exercise (8). Mitochondrial density is strongly linked with increased endurance performance. As Huertas writes, “The increase in mitochondrial volume seems to be one of the most important effects that improves endurance performance” (9). Athletes can increase mitochondrial density through intense efforts (close to VO2 max), but also through the accumulation of training volume (10). In a recent study, Sindre Mølman et al. also found that “higher training frequencies were associated with larger increases in mitochondrial content” (11). That is, athletes who ran more than 6 times a week had higher mitochondrial content than those who ran 2-5 times a week.

·      Capillarization: the process of increasing capillaries, which are small blood vessels in the muscle fibres. When we exercise, blood flows through capillaries in the working muscles, delivering oxygen, nutrients and clearing waste product. Gliemann writes that “capillarization is vital for exercise capacity” (12). Athletes can increase and maintain capillarization through both low-moderate intensity exercise and high-intensity exercise. Easy running, therefore, offers an opportunity to increase or maintain capillarization while still recovering from high-intensity workouts.

·      Improvements in running economy: greater running volume results in neuromuscular changes which allow athletes to run at higher speeds while expending less energy. One study, which compared people running more than 30 miles a week (~49kms) with others running less than 10 miles a week (~16kms), found that “The better trained runners demonstrated more spring-like behaviour in their lower leg tendons, which helped propel the body forward more efficiently” (13).

So, we can see that easy running has many benefits, and if done properly, can complement our harder workouts. However, if the intensity is too high, we not only risk further delaying our recovery, but we also risk entering a cycle of overtraining, where we’re less and less recovered for each proceeding session, and our performances either stagnate or continue to burrow further and further down over time. 

Note: Some people make a distinction between “easy runs” and “recovery runs”. However, given the nature of our supercompensation cycle, easy runs should be performed at an intensity that allows us to recover in between hard sessions. Therefore, strictly speaking, easy runs are recovery runs.

Just to be clear, easy runs are not long runs (though some long runs are done at an easy intensity), they are not progression runs, steady runs or tempos - all of which will require their own designated recovery period.

Now, there may be certain periods of the year when an athlete isn’t following a strict system of 2-3 hard workouts (plus a long run) a week. Perhaps they’re in a base period with no formalized hard sessions. In this instance, recovery may not be as much of a priority for general runs, and so license is given to push the pace. But this isn’t the structure that most runners adhere to for most of the year. The structure does tend to revolve around 2 or 3 hard workouts a week, and most runners do recognize that when running easy, there is a threshold of intensity, beyond which they’ll further delay their recovery from the previous stress. The problem is - this threshold is at a much lower intensity than most runners estimate.

The estimations:

“Zone 2”

The phrase “Zone 2” has become very trendy of late, most likely due to the success of Tadej Pogacar in cycling, whose coach, Inigo San Milan, is one of the leading proponents of this training intensity.

However, I’m skeptical of its application in running.

For starters, we get varying and contradictory definitions of what it is. In the words of Senior Fitness and News Editor, Amber Sayer, the common understanding is: “because Zone 2 training is quite easy, it fully allows your body to recover from hard workouts” (14). That’s all well and good, and it lines up with Weidenbach’s definition of Zone 2 occurring at 60-70% of heart rate max (15). However, others claim that it’s an intensity much closer to LT1 (the point at which lactate rises above baseline; usually around marathon pace intensity, which can be close to 85% max heart rate in trained athletes). Inigo San Milan defines it as the latter, and in a podcast with Peter Attia, he mentions that “Zone 2 often occurs at a lactate concentration between 1.7 – 1.9 mmol/l” (16) or as Vossen puts it, “for trained athletes, this lactate concentration is slightly above resting values. This corresponds very closely to the intensity of Lactate Threshold 1 (LT1)” (17). This certainly isn’t the same intensity that Sayer or Weidenbach are referring to above or what Matt Fitzgerald (author of books such as 80/20 Running and How Bad Do You Want It?) is referring to when he invokes the term “Zone 2”. Fitzgerald defines the upper limit of Zone 2 as “80% of heart rate max” (18) or 65% of “maximal aerobic speed” (which is the fastest pace you could sustain for 6 minutes)”. If you’re not familiar with that term, it’s commonly referred to as “Velocity at VO2 Max” (19). Using myself as an example, I estimate, based on a recent 3,000m performance of 9:16, that I could hold roughly 19.7km/h (~3:03/km) for an all-out 6 minute effort. If I plug these calculations in, I’d be given a pace at the upper limit of Zone 2 of 4:41/km. Now, let’s compare this pace with Inigo San Milan’s definition. My conservative estimate for LT1, based on a marathon result of 2:49:22 (LT1 is commonly defined as a pace one could hold for 2-2.5 hours), is a pace of 3:56/km. 

So, in one instance, I’m given an upper limit of roughly 4:41/km and the other, I’m given 3:56/km. Even with an adjustment for error, that’s a very big disparity, which would have huge ramifications depending on which I followed. One would correspond with a percentage of max heart rate (on a flat surface without dehydration or fatigue) roughly in the range of 68-74%, and the other of 79-85%. If we compare this with Weidenbach’s definition (60-70% of heart rate max), we see a slight overlap with Fitzgerald’s, but in Fitzgerald’s own words, “a little above Zone 2 is still above Zone 2” and “if you’re above Zone 2, you’re not getting the full benefits of Zone 2 training”.

But how can we know we’re not above (or below) Zone 2 when the prescriptions vary so widely? And if “Zone 2” refers to anything at all, then surely all three of these definitions cannot be correct.

But perhaps that’s just it, Zone 2 is so broad a term that all of these definitions are encompassed within it (as the graph below demonstrates). If that’s the case, then there may be very different ways of following the advice to “stick to Zone 2 during easy runs”. Some may do it in the lower half of the zone, where they stand a much better chance of adequately recovering between hard workouts. Others may do it right at the very top of the range, pressing up against LT1, with a heart rate 20-30 beats higher. In this instance, the likelihood of injury or overtraining would be substantially raised. However, both would still technically be in Zone 2. Therefore, “sticking to Zone 2” for easy runs is too general a rule to have much utility in the program of a serious runner. And the top of Zone 2 certainly isn’t a delineation point between a recovery intensity and a further stress. In other words, it may be true that the right intensity for an easy run is found in Zone 2, but not all intensities in Zone 2 are right for easy runs.

Above: A visual representation of how HR training zones relate to an athlete’s lactate profile (Eastman, 20).

Aside from this, the proliferation of Zone 2 training is largely down to San Milan and the benefits he claims this intensity produces. If these benefits are best acquired by running at a higher intensity, one that more closely resembles Canova’s “Aerobic Fat Power” (21) runs, then we may want to question the claims made by Fitzgerald, Sayer and Weidenbach in relation to Zone 2. If our goal is to best stimulate mitochondrial activity, then perhaps we could structure our training to better accommodate a San Milan style workout. But as it stands, with such conflicting information on Zone 2, we have no incentive to do so. What seems to be happening at the moment is a mixing together of all the information from different sources on what Zone 2 is, and what it does for us.

Therefore, many runners are operating under one of the following false assumptions:

·      I’ll fully recover in time for my next workout as long as I run at a pace that’s slightly slower than LT1 in between.

·      Running at 60-70% (or 65-80%) of max heart rate is the best way to stimulate mitochondrial activity.

·      Zone 2 is a pace that’s faster than my usual easy run pace, but slower than marathon pace (partly true, but not wholly true, for the same reason given at the end of the preceding paragraph).

·      I’ll see greater improvements in performance if I run at the above-mentioned intensity on easy days, rather than a lower intensity.

Finally, my last point on Zone 2 training relates to San Milan and the sport in which this training was popularized: cycling. We can’t ignore that cycling is a low-impact sport, which enables athletes to spend more time in higher intensity training zones compared to running. It may be possible – and even optimal – for cyclists to do 4-5 x 4 hour rides per week at an intensity close to LT1. However, the high-impact nature of running causes considerable muscle damage that exponentially increases as we go up the intensity spectrum. To return to the example of famed coach Renato Canova – widely considered to be the best coach of marathon runners in the world – he does prescribe lengthy runs at this intensity throughout his marathon blocks, but they are in no way “easy runs”. They are performed at 95% of goal marathon pace, which in elite athletes, sits roughly below LT1 or right at “Fat Max”, the intensity at which the maximum amount of fat is burned per hour. If we once again compare this with San Milan’s “Zone 2”, we find that while in conversation with Peter Attia, he agreed with the statement: “what we’re seeing is zone 2 occurring at the point of maximum fat oxidation” (22). In other words, at “Fat Max”. Therefore, we already have an example of how San Milan’s Zone 2 can be applied with great success in running. However, it is not an easy intensity. Canova treats these runs as workouts in themselves, with lots of recovery programmed either side.

Daniels’ E Pace

Another estimation for the right easy running intensity/pace is found in Daniels’ Running Formula (23). The exercise physiologist and running coach, Jack Daniels (dubbed the “world’s best running coach” by Runner’s World Magazine) describes “E running” as the lowest intensity run that a distance runner will undertake in a training program. It is defined as “typically an intensity 59-74% of VO2 Max or about 65 to 78% of maximum heart rate”. When discussing the purpose of E runs in a training program, Daniels states “E days are included so that you get proper recovery from the quality sessions…” Daniels then goes on to list particular paces for E runs, relative to a runner’s “VDOT” score (an estimate of VO2 Max, based on race performances).

When I locate the score that best aligns with my own performances from 3-10k, I’m given an “E pace” range of 4:02 – 4:34/km. Immediately, I’m wary. Almost 20 years of running experience tells me that these paces are far too intense to be considered “easy”, in the sense that they would allow me to “get proper recovery from the quality sessions”. However, maybe my own biases are preventing me from training at optimal intensities. Perhaps my approach is too conservative. If I plug a much faster time into these “VDOT” tables and see how it stacks up against the reality of what the world’s best runners are doing, maybe then I’ll get a better idea of the practicality of this prescription. If I place a performance of 27:24 for 10k (roughly 6 minutes faster than my own personal best) into the tables, I’m allocated an “E pace” range of 3:19-3:46/km. The great thing about running in 2024 is we have access, via exercise apps and running forums, to the entire training logs of many of the world’s best runners. I’ll explore this in more detail in later paragraphs, but for the moment, I can assure you that no elite runner of this calibre (that I can find) is getting close to the upper three quarters of that range during anything considered an “easy run”. Some may touch the very bottom end at times, but most stick to the range that I was prescribed (as a 33 minute 10k runner) of 4:02-4:34/km.

So, are the elites getting it wrong? Are they also being too conservative?

I find this hard to believe, as running is an extremely competitive sport. Through a process akin to that of natural selection, the best talent rises to the top, but so too do the best training approaches. In the 21st century, one cannot be among the top 0.000001% of the world’s distance runners without exceptionally effective training.

Therefore, if I too am to carry out exceptionally effective training, how can my easy pace be the same as someone who is 6 minutes faster than me over 10k?

It can’t.

So, if we can’t simply “stick to Zone 2 for easy days” (because it’s too broad) and Daniels’ “E pace” isn’t practical, what intensity should we be running?

As hinted above, we should be looking at what works for the very best. If running at paces close to LT1 or “Fat Max” or even close to 80% of heart rate max for easy runs was the most effective way to train, then we would see it in the training of elites. If we examine the training of the very best runners, we don’t see this trend. In fact, we see something very different. Elite runners tend to do the bulk of their mileage at a much lower intensity than the Zone 2 defined by San Milan or even the one defined by Fitzgerald.

Let’s look at examples:

We’ll start with famed coach, Renato Canova. Fortunately for us, he’s a regular poster on the running website Letsrun where he recently published Emil Cairess’ entire training log leading into the 2024 London Marathon (24). Emil went on to run 2:06:46, and then finished 4th in the Paris Olympic Marathon.

Thanks to John Davis at Running Writings (25), a sample week (with paces) has been organised below:

M 88’ at 4:05–3:55/km 5 x 120m strides 41’ at 4:10–4:00/km

Tu 20’ warmup + 12 sets of: 1k avg. 3:26.2, 1k avg. 2:49.6

W 89’ at 4:05–3:55/km 56’ at 4:10–4:05/km

Th 41’ at 4:10–4:00/km 39’ at 4:00–3:50/km

F 39’ at 4:05–3:50/km 40’ at 4:05–3:55/km

Sa 5’ warmup + 45 km at 3:17/km

Su 49’ at 4:10–4:00/km 31’ at 4:10–4:00/km Total for week: 204 km

This sample is week 11 of a 16 week block, with the race (The London Marathon) taking place on a Sunday at the end of the 16th week. I chose this example as it’s done at sea level (in Leeds, UK) rather than at altitude in Kenya. Therefore, we get a better picture of Emil’s easy pace relative to his marathon time (also done at sea-level).

We immediately see that the majority of Emil’s runs are done between 3:50-4:10/km. We would classify this as easy mileage. Emil’s half marathon personal best is 60:01, which is 2:50.6/km, and his marathon personal best is 2:06:46, which is 3:00.2/km.

That means his easy runs are between 60-80 seconds/km slower than his half marathon pace, and between 50-70 seconds/km slower than his marathon race pace. When we look at this as a proportion of race speed (a much better way of doing conversions in instances such as these), we see that Emil’s speed during his easy runs is roughly 68-74% of his half marathon pace, and 72-78% of his marathon pace.

If we map Emil’s conversion onto a 2:59 marathoner, someone who holds a pace of 4:15/km for the 42.195km distance, we get an equivalent easy pace range of 5:27/km-5:54/km. I doubt you know many sub 3-hour marathoners who run anywhere near this slowly on their easy days.

Perhaps you haven’t done a marathon, and so this conversion doesn’t give a clear point of reference. In this case, Emil has also run 27:34 for 10k; a pace of 2:45.4/km. Mapped onto a 36 minute 10k runner, we get an easy pace range of 5:00 - 5:26/km. Again, very few runners of this ability ever run close to the lower end of this pace range.

To compare this with Daniels’ E Pace range, I’ll return to my own conversion. A 33:19 10k converts to an easy pace range of 4:38-5:02; a drastic shift away from the 4:02 – 4:34 encouraged by Daniels.

So, you might be thinking, ‘okay, that’s just one marathon runner, that doesn’t prove anything.’ But again, thanks to the internet, we can access the training of many elite runners and quickly gather a big enough sample group to spot trends.

Below is a chart that lists 24 current elite distance runners, who specialize in distances ranging from the 1,500m up to the marathon. They were selected based on the quality of their performances in 2024 and the accessibility of their training (from Strava, 26). All appear in the top 20 continental performances in a distance event for 2024. I’ve listed their personal best at a preferred distance in the first column; their easy run pace range gathered across a random 2 week sample in the second; and the percentage at which they run their easy pace relative to their 10k best (taken from their World Athletics (27) profile or The Power of Ten (28) website) in the third. I’ve selected 10k as a yardstick for uniformity’s sake; it’s also somewhat of a middle ground for the athletes below and should be relevant to a large population of runners. I’ve avoided using athletes who only partially upload their training (in a set period), as easy runs tend to be the first culled and so we don’t get the full picture of their easy pace range.

To calculate the percentage of paces, I’ve divided the speed of an athlete’s easy pace by the speed of their 10k. For example, a 40 minute 10k runner has a speed of 15km/h. Their easy pace might be 5:00/km, which is 12km/h. 12 divided by 15 equals 0.8 (or 80%). Therefore, in this example, the 40 minute 10k runner’s easy pace would be 80% of their 10k pace.

Athlete (Nation)	Best Distance - PB	Easy Pace Range	Easy Pace as Percentage of 10k Pace
Brett Robinson (AUS)	Half Marathon – 59:57 (NR) (2:50.5/km)	4:01 - 4:35/km (6:28 - 7:22/mile)	61-69%
Andy Buchanan (AUS)	Marathon – 2:06:22 (NR) (2:59.7/km)	4:08 – 4:37/km (6:39 - 7:26/mile) (Some “recovery” runs as slow as 5:04/km)	62-69%
Isobel Batt-Doyle (AUS)	10k – 31:12 (NR) (3:07.2/km)	4:14 – 4:42/km (6:48 - 7:34/mile)	66-74%
Rose Davies (AUS)	5000m – 14:41 (NR) (2:56.2/km)	4:07 – 4:46/km (6:37 - 7:40/mile)	66-76%
Emil Cairess (GBR)	Marathon – 2:06:46 (3:00.2/km)	3:50 - 4:10/km (6:10 - 6:42/mile)	66-72%
Jack Rowe (GBR)	5000m – 13:04 (2:36.8/km)	3:59 – 4:31/km (6:25 - 7:16/mile)	62-70%
Hannah Nuttall (GBR)	5000m – 14:52 (2:58.4/km)	4:22 – 4:46/km (7:01 – 7:40/mile)	*65-71%    (equivalent based on 5k) (29)
Charles Hicks (GBR)	5000m – 13:09 (2:37.8/km)	4:07 - 4:22/km (6:37 – 7:01/mile)	63-67%
Clayton Young (USA)	Marathon – 2:08:00 (3:02/km)	4:08 – 4:36/km (6:39 – 7:24/mile) (altitude)	62 – 68%
Joe Klecker (USA)	5000m – 12:54 (2:34.8/km)	3:57 – 4:20/km (6:21 – 6:58/mile) (altitude)	63 – 69%
Keira D’Amato (USA)	Marathon – 2:19:12 (3:17.9/km)	4:32 – 5:05/km (7:18 – 8:11/mile) (altitude)	61-69%
Alicia Monson (USA)	5000m – 14:19 (NR) (2:51.8/km)	4:21 – 4:47/km (7:00 – 7:42/mile) (altitude)	63-69%
Robert Farken (GER)	1500m – 3:32.1 (2:21.4/km)	3:56 – 4:32/km (6:20 – 7:18/mile)  (altitude) *Some “recovery” runs as slow as 4:50/km	*62-71% (equivalent based on 3,000m PB)
Malindi Elmore (CAN)	Marathon – 2:23:30 (3:24.1/km)	4:26 – 5:02/km (7:08 – 8:06/mile)	65-74%
Sintayehu Vissa (ITA)	1500m – 3:58.1 (NR) (2:38.7/km)	4:25 - 4:46/km (7:06 – 7:40/mile) (altitude)	*65-70%          (equivalent based on 3,000m PB)
Jacob Boutera (NOR)	3000m Steeplechase – 8:21 (2:47/km *with barriers)	4:20 – 4:45/km (6:58 – 7:39/mile)	*59-65%  (equivalent based on 3,000m PB)
Jacob Simonsen (DEN)	Marathon – 2:07:51(NR) (3:01.8/km)	4:22 - 4:51/km (7:01 – 7:48/mile) (some “recovery” runs as slow as 5:05/km)	59-66%
Maureen Koster (NED)	5000m – 14:44 (2:56.8/km)	4:22 - 4:55/km (7:01 – 7:55/mile) (altitude) *Some “recovery” runs as slow as 5:05/km	64-72%
Juliette Thomas (BEL)	Half Marathon – 1:09:48 (3:18.5/km)	4:25 - 4:49/km (7:06 – 7:45/mile)	66-72%
Emma Bates (USA)	Marathon – 2:22:10* (Boston) (3:22.2/km)	4:28 - 4:58/km (7:11 – 7:59/mile) (altitude)	65-72%
Yemaneberhan Crippa (ITA)	Half Marathon – 59:26 (NR) (2:49/km)	3:43 - 4:17/km (5:59 – 6:54/mile) (altitude)	63-73%
Nick Griggs (IRL)	3000m – 7:36 (2:32/km)	4:09 - 4:27/km (6:41 – 7:10/mile)	*62-66% (equivalent based on 5k)
Marta Perez	1500m – 3:57.7 (NR) (2:38.5/km)	4:17 - 4:49/km (6:54 – 7:45/mile)	*65-73%  (equivalent based on 3k)
Sophie O’Sullivan	1500m – 4:00.2 (2:40.1/km)	4:20 - 4:46/km (6:58 – 7:40/mile)	*66-72%  (equivalent based on 3k)

Males have been highlighted in blue; females in red. Paces may have been affected by altitude (roughly 1-2%) and so I’ve marked where relevant, but this may not be as severe for athletes living at altitude most of the year, especially given the relatively low intensity of these runs. Hills, running surface and weather will also slow the pace. However, elite track and road athletes tend to have a habit of seeking out the flattest routes and the most manicured paths. Other things to note; I’ve excluded an athlete’s weekly long run from the overall calculation, as it doesn’t sit comfortably within the definition of an ‘easy’ run. Also, to satisfy those who claim a recovery run and an easy run aren’t the same, I’ve excluded runs that have been marked as “recovery” (or clearly appear to be so), provided they fall well outside the general range, and are less than 40 minutes in length. Warm-ups, cool downs, strides and sessions have all been excluded.

Some noticeable trends:

The overall easy pace range was between 59 and 76% of 10k pace. However, 19 of 24 athletes did not exceed 72% of 10k pace on easy runs. All athletes ran at 66% or lower on at least some of their easy runs. The average easy pace range was between 63 and 70% of 10k pace. The average raw pace range was between 4:12/km and 4:41/km. However, when we separate males and females, we notice a few differences. Despite the men running at slightly faster raw paces, the females tended to run at a slightly faster pace range relative to their 10k pace; 65 – 72%, compared to 62 – 69% for males. 11 out of the 12 males did easy runs at 63% of 10k pace or below, while this was replicated by only 2 out of 12 females. Despite this, the equal slowest average pace for a run (recovery or otherwise) was recorded by a male (Jacob Simonsen) at 5:05/km. When we consider that Jacob’s marathon personal best is 2:07:51 - a pace of 3:01.8/km – we can see that runs more than 2:00/km slower than marathon pace still have a place in an elite distance runner’s training regime.

So, let’s look at how this conversion translates to the sub-elite, club and recreational levels. If we use our average easy pace range of 63-70%, we get easy paces for athletes running the following 10k times:

30:00	4:17 - 4:46/km (6:54 – 7:40/mile)	40:00	5:42 – 6:20/km (9:10 – 10:11/mile)
31:00	4:26 - 4:55/km (7:08 – 7:55/mile)	41:00	5:51 - 6:30/km (9:25 – 10:28/mile)
32:00	4:34 - 5:05/km (7:21 – 8:11/mile)	42:00	6:00 – 6:40/km (9:39 – 10:44/mile)
33:00	4:42 - 5:14/km (7:34 – 8:25/mile)	43:00	6:09 - 6:50/km (9:54 – 11:00/mile)
34:00	4:51 – 5:24/km (7:48 – 8:41/mile)	44:00	6:17 – 6:59/km (10:07 – 11:14/mile)
35:00	5:00 - 5:33/km (8:03 – 8:56/mile)	45:00	6:26 - 7:08/km (10:21 – 11:29/mile)
36:00	5:08 – 5:42/km (8:16 – 9:10/mile)	46:00	6:34 – 7:18/km (10:34 – 11:45/mile)
37:00	5:17 - 5:52/km (8:30 – 9:26/mile)	47:00	6:43 - 7:28/km (10:48 – 12:01/mile)
38:00	5:25 – 6:02/km (8:43 – 9:42/mile)	48:00	6:51 – 7:37/km (11:01 – 12:15/mile)
39:00	5:34 - 6:11/km (8:57 – 9:57/mile)	49:00	7:00 - 7:47/km (11:16 – 12:31/mile)

So, what to make of this?

I can hear the ever-present argument that this isn’t relevant to recreational runners because “recreational runners shouldn’t copy the training of elites’, but in this instance, where the elites are being far more conservative than the rec-runners, it should at least guide us in our training intensity and present a red-flag for those who constantly exceed this conversion and wonder why they’re always battling injuries and/or never seem to improve.

Others will argue that ‘of course elites run slower on their easy days, they’re doing such big mileage that they have to.’

But this is a self-defeating argument for two reasons:

·      Firstly, if our intention is to improve as much as possible, and others who’ve managed to reach the highest level have done so by slowing down their easy runs (so that they can run more), then shouldn’t we all be following this process? If the argument then follows that ‘rec-runners can’t run more because they’ll get injured’, then surely running faster on easy days will only raise that risk. Running slower (but more) has obviously proven (in the eyes of elites) to not only be the more optimal way of training, but also the more effective way of managing load. And that’s before I point out the obvious inverted argument; ‘rec-runners have to do such low-mileage because they run everything too fast’

·      Secondly, training load is relative to the individual. Athletes who regularly run 160-200kms a week have accumulated a much greater capacity for load than athletes running 70kms a week (for example). Given that the vast amount of the additional mileage carried out by high mileage athletes is done in the form of easy running, then each workout is a much smaller portion of their overall load. A hard workout is thus a much greater stress (relatively) for a lower mileage athlete, and therefore, recovery (running slower on easy days) is all the more necessary.

There’s also the common argument that ‘rec-runners’ don’t have the time to do high-mileage (because they have work and families), and so running faster is a “hack” to get more gains with less volume.

Working full time and family commitments will certainly be a barrier to effective training, and many people will find themselves compromising in this position. I don’t begrudge these people; however, I’m attempting to address the runners who are capable and willing to make the time for the most effective training.  Running, for the most part, is a relatively time-efficient sport, and most people could reach their full potential off a commitment of no more than 15 hours a week. Regardless, I disagree that running faster on easy days would produce better results than running the appropriate intensity, for the reasons previously mentioned; most notably, supercompensation. In this instance, running faster on easy days is actually less time efficient, because it delays the recovery period until the body is ready for another hard workout (where more potent gains are made). I stress again, if an athlete’s training program doesn’t include adequate recovery to enter the supercompensation phase, they will limit rather than enhance their gains, and their performances will stagnate much sooner - or even regress – as a result. However, this only applies if one is interested in an effective training system. It’s very easy to have a time-efficient training system that isn’t effective. In this instance, you don’t have to adhere to a supercompensation cycle at all. You simply stick to a routine that’s convenient but doesn’t produce improvements in performance.

Conclusion:

If we choose to follow a weekly training schedule, because it’s proven successful for elites, then why do we not follow the relative intensity of their easy runs? We emulate the intensities of every other type of run. We do 400s at mile pace, relative to our own ability level, rather than the raw pace that elites do them. We do vo2 max intervals proportional to our own ability level, rather than the raw pace that elites do them. We do threshold sessions, either as continuous runs or intervals – (Norwegian Method aside) at roughly 1 hour pace, and again proportional to our own ability – not at the raw pace that elites do them. So, why do we not follow the same logic for arguably the most important piece of the puzzle?

If we know that running at the same raw pace of elites (or as close as we can get) in these workouts would not produce the same adaptations, because we’d be working completely different energy systems, then why do we think “easy running” at the same or a similar raw pace will produce the equivalent training effect in us as it does in elites?

To add to this, we understand in other workouts that running at a slightly lower intensity delivers a more desirable stimulus than running at a faster pace. Tempo runs or threshold intervals are done sub-maximally. Everyone understands that pushing the pace on these runs defeats the purpose of the workout, and yet, a similar reasoning fails to be employed for easy runs.

At the risk of overstating my case, I give one last analogy. We should look at the training schedule of elite runners as a recipe for creating the best possible performance. To make this analogy as cliché as possible, let’s compare this recipe to that of a cake. If we wanted to create the same cake albeit in a smaller portion, then we would simply reduce all the ingredients by the same proportion across the board. We would not say, ‘well I’ll take out 50% of the flour, but add 30% more sugar’. If we did, we wouldn’t have the same cake at the end, and we wouldn’t be following the recipe that’s proven time and again to create the best possible performance. 

References:

1.         Goddard, Ed. In, Threlfall, Brady, host. ‘Road to Gold Coast: Episode 3’. Inside Running Podcast. 2023. insiderunningpodcast.com/

2.         Moffatt, Nick. ‘The Principle of Supercompensation’. NDM Sports and Personal Training, April 3, 2019. ndmcoaching.co.uk/2019/04/03/applying-the-principle-of-super-compensation/ Accessed December 22, 2024

3.         American College of Sports Medicine. ‘A Road Map to Effective Muscle Recovery’. ACSM, October 3, 2019. www.acsm.org/docs/default-source/files-for-resource-library/a-road-map-to-effective-muscle-recovery.pdf 

4.         Rutten, Leon. ‘Supercompensation’.  Equestic, November 11, 2022. www.equestic.com/supercompensation/ Accessed December 22, 2024

5.         Rose, Alexandra. ‘The Cortisol Creep: Is HIIT Stressing You Out?’. Healthline, April 14, 2021. www.healthline.com/health/fitness/the-cortisol-creep Accessed December 22, 2024.

6.         Mullner, Justin. In: Mateo, Ashley. Cortisol and Exercise: What You Need to Know. www.runnersworld.com/uk/health/mental-health/a60125903/cortisol-and-exercise/

7.         Casado, Arturi, et al. ‘World-Class Long-Distance Running Performances Are Best Predicted by Volume of Easy Runs and Deliberate Practice of Short-Interval and Tempo Runs’. The Journal of Strength and Conditioning Research. Vol. 35, No. 9, 2021. pp. 2525-2531. journals.lww.com/nsca-jscr/fulltext/2021/09000/world_class_long_distance_running_performances_are.25.aspx Accessed March 5, 2025

8.         Brooks, George A, et al. ‘Role of Mitochondrial Lactate Dehydrogenase and Lactate Oxidation in the Intracellular Lactate Shuttle’. Proceedings of the National Academy of Sciences of the United States of America. Vol. 96, No. 3, 1999. pp. 1129-1134. www.pnas.org/doi/full/10.1073/pnas.96.3.1129 Accessed February 27, 2025

9.         Huertas, Jesus R, et al. ‘Stay Fit, Stay Young: Mitochondria in Movement: The Role of Exercise in the New Mitochondrial Paradigm’. Mitochondria at the Crossroads of Survival and Demise. Special Issue of Oxidative Medicine and Cellular Longevity. Para. 19. onlinelibrary.wiley.com/doi/10.1155/2019/7058350 Accessed February 27, 2025

10.  Hutchinson, Alex. ‘How to Maximize Your Mitochondria’. Runner’s World, June 7, 2016. www.runnersworld.com/training/a20800596/how-to-maximize-your-mitochondria/ Accessed December 22, 2024

11.  Mølman, Knut S, et al. ‘Effects of Exercise Training on Mitochondrial and Capillary Growth in Human Skeletal Muscle: A Systematic Review and Meta-Regression’. Sports Medicine. Vol. 55. 2024. pp. 115-144. para. 4. https://link.springer.com/article/10.1007/s40279-024-02120-2 

Accessed March 5, 2025

12.  Gliemann, Lasse. ‘Training for skeletal muscle capillarization: a Janus-faced role of exercise intensity?’ European Journal of Applied Physiology. Vol. 116. 2016. pp. 1443-144. link.springer.com/article/10.1007/s00421-016-3419-6 Accessed March 6, 2025

13.  Verheul, Jasper, et al.‘How High-Mileage Running Makes Muscles and Tendons More Efficient’. Independent, February 20, 2017. www.independent.co.uk/life-style/health-and-families/healthy-living/how-highmileage-running-makes-muscles-and-tendons-more-efficient-a7586096.html Accessed December 22, 2024

14.  Sayer, Amber. ‘Zone 2 Training: Unlock Endurance, Boost Performance, and Go the Distance’. Marathon Handbook, December 5, 2024.  marathonhandbook.com/zone-2-training-the-science-benefits/ Accessed December 22, 2024

15.  Weidenbach, Charlotte. In: McPhillips, Kellis. ‘Why Easier Efforts Might Just Improve Your Cardiovascular Fitness’. Peloton, December 21, 2023. www.onepeloton.com/en-AU/blog/zone-2-cardio/ Accessed December 22, 2024

16.  San Milan, Inigo. Attia, Peter. (2022). In: Vossen, Loek. ‘Zone 2 Training: Benefits, Science and How-To Guide’. INSCYD,  inscyd.com/article/zone2-training/#:~:text=In%20a%20podcast%20with%20Peter,that%20stimulates%20mitochondrial%20function%20most Accessed December 22 2024

17.  Vossen, Loek. ‘Zone 2 Training: Benefits, Science and How-To Guide’. INSCYD,  inscyd.com/article/zone2-training/#:~:text=In%20a%20podcast%20with%20Peter,that%20stimulates%20mitochondrial%20function%20most Accessed December 22 2024

18.  Fitzgerald, Matt. ‘You’re Not Really Training In Zone 2 (You Just Think You Are)’. Strava Stories, March 20, 2024. stories.strava.com/articles/youre-not-really-training-in-zone-2-you-just-think-you-are#:~:text=Zone%202%20training%20sessions%20%2D%20long,intensity%20interval%20training%20(HIIT). Accessed March 6, 2025

19.  Walker, Owen. ‘Maximal Aerobic Speed (MAS)’. Science for Sport, April 9th, 2024. www.scienceforsport.com/maximal-aerobic-speed-mas/#:~:text=Maximal%20aerobic%20speed%20(MAS)%20is%20simply%20the%20lowest%20running%20speed,monitor%20training%20loads%20more%20accurately. Accessed December 22, 2024

20.  Eastman, Renee. ‘Lactate Profile’. CTS. trainright.com/lactate-threshold-and-how-do-cyclists-train-it/ Accessed December 22, 2024

21.  Canova, Renato. In: Davis, John. ‘Review and summary of Marathon Training - A Scientific Approach by Renato Canova’. Running Writings, June 19, 2023. para. 37-38.  runningwritings.com/2023/06/canova-marathon-book.html#:~:text=Canova%20and%20Arcelli%20recommends%202,fat%20cells%20and%20muscle%20fibers. Accessed March 6, 2025

22.  Attia, Peter, host. ‘Deep Dive Back into Zone 2: Inigo San Milan, Ph.D (Pt.2)’. The Drive. Episode 201. March 28, 2022. peterattiamd.com/inigosanmillan2/ Accessed March 8, 2025

23.  Daniels, Jack. 2014. Daniels’ Running Formula: Third Edition. Human Kinetics. Champaign, IL. pp. 47-50, 81, 86.

24.  Renato Canova. ‘Renato, Can You Talk About the Preparation of Emil Cairess 2:06. LetsRun. April 22, 2024. www.letsrun.com/forum/flat_read.php?thread=12669697#post-9 Accessed March 6, 2025

25.  Davis, John. ‘Modern Marathoning with Renato Canova: Analysis of Emile Cairess’ Training Before the London Marathon’. Running Writings, May 1, 2024. runningwritings.com/2024/05/renato-canova-marathon-training-emile-cairess.html  Accessed March 6, 2025  

Additional Resources:

26.  Strava. Athletes. www.Strava.com 

27.  World Athletics. Athlete Profiles. Personal Bests: worldathletics.org/athletes

28.  Power of Ten. www.thepowerof10.info/ 

29.  Humphrey, Luke. ‘Race Time Equivalency Calculator’. lukehumphreyrunning.com/hmmcalculator/race_equivalency_calculator_reverse.php