Hard days are hard, easy days are easy
Despite the simplicity of this message, polarised training is a topic that has excited, infuriated and baffled many amateur endurance athletes.
Popularised by top physiologist Stephen Seiler, polarised training has since been promoted in countless articles and books like 80/20 Running and 80/20 Triathlon by Matt Fitzgerald. However, despite the volume of material written on the topic, it remains a popular topic to debate on internet forums and seems to divide people like nothing else (apart from almost anything on Twitter).
Dr Seiler has published a series of papers that examine the training patterns of elite athletes across various endurance disciplines like cycling, running, skiing and rowing. He found a remarkably consistent pattern in the balance between easy sessions and hard workouts. Before we discuss what that pattern was, let’s establish a system for categorising workouts.
Three Zone Model
It’s common practice for endurance athletes to assign training zones to sessions in terms of power, pace or heartrate. The number of zones varies, often between 5 and 7, with rather complicated names like “anaerobic capacity” and “neuromuscular power”. Dr Seiler has helpfully simplified this to just 3 zones, which we’ll call “low”, “moderate” and “high”.
Unfortunately, these are defined by rather more complex physiological parameters that we could refer to by a number of different names. For the sake of argument, we’ll refer to them in terms of lactate as that’s what endurance athletes are most likely to be familiar with, even if they haven’t had a lactate test themselves. We could use ventilatory thresholds (VT1 and VT2), for example, but the discussion would be much the same.
Dr Seiler has helpfully simplified this to just 3 zones, which we’ll call “low”, “moderate” and “high”
When we exercise at low intensity, most of our energy comes from the aerobic metabolism, which doesn’t generate any lactate. This means lactate levels stay low, possibly even lower than at rest because we start to use some as fuel.
Zone 1 is defined as being below LT1 (lactate turning point 1), where lactate levels are no higher than at rest. It’s characterised by easy breathing, where you could comfortably hold a conversation. Think recovery pace and steady endurance work.
As effort ramps up, we start to rely more on anaerobic pathways that generate lactate to supplement our aerobic metabolism. This generates increasing amounts of lactate. In response, our body shuttles that lactate around and uses it as fuel and we see lactate levels in the blood start to increase. However, we’re still in control and lactate is being used as fast as it is generated.
In Zone 2, between, LT1 and LT2 lactate turning point 2), lactate concentrations are elevated in the blood but would stay constant if we stayed at the same pace. Breathing is a bit heavier but you might be able to speak in short sentences.
Eventually, we can’t handle all the lactate that is being generated and it starts to build up. Now the metabolic clock is ticking!
Zone 3 (high intensity) begins at LT2, which is pretty close to functional threshold power (FTP) or threshold running pace. It’s roughly the intensity we could maintain for an hour of continuous work. Anywhere above this point, lactate continues to accumulate in the blood and eventually we are forced to slow down. Breathing is heavy and you can only manage single words or short phrases, most of which might end in “off”.
Theory into practice
Using this three zone model, here are some typical sessions and where they would fit in this system:
The Polarised or 80/20 model
When Dr Seiler looked across different endurance sport, he found that elite athletes’ training had converged to a remarkably similar pattern - across the season, 80% of sessions were “easy” aerobic development and just 20% were “moderate” or “hard”.
I believe some of the confusion with polarised training comes from the early studies, which found that athletes were training almost entirely in zone 1 and zone 3, with very little work in zone 2. This led to the idea of zone 2 training as being a “grey zone”. Consequently, people argued that zone 2 training had no value and should be avoided at all costs. Later studies found that some disciplines (typically longer steady state efforts) favoured a pyramidal distribution, with more work in zone 2 than zone 3.
However, the one fact that remained constant across all studies was the high volume of zone 1 training – almost always around 80%.
Typically, longer events like Ironman triathlon might favour more time in zone 2, while a short event like a UK hill climb might benefit from a more polarised approach. The most effective strategy will also depend on the individual athlete, their athletic history and how they respond to different types of training.
Selles-Perez et al. (J Sports Sci Med. 2019;18(4):708‐715. Published 2019 Nov 19.) found, in their study “Polarized and Pyramidal Training Intensity Distribution: Relationship with a Half-Ironman Distance Triathlon Competition” found that a pyramidal training distribution (77.9%/18.8%/3.3%) with more time in zone 2 than in zone 3 was more effective than a polarised distribution (84.5%/4.2%/11.3%). However, note that the pyramidal distribution still involved 78% of training in zone 1.
An alternative to this is to focus training on intensities in the middle zone in the belief that zone 2 training, being harder, must be more effective than zone 1. This results in a threshold intensity distribution.
Is polarised training right for recreational athletes?
It’s fine for the pros, but I can’t be noodling around at easy intensity all the time. I need to get fit!
Pros have more time to train so accumulate a huge volume of easy aerobic training. Even a pretty dedicated amateur athlete (depending on the discipline) might only train 10 hours a week. Should you really spend 8 hours of that going easy? Wouldn’t you get fitter just training hard most of the time?
There have been a few studies that looked into this for trained (but not elite) runners and cyclists and the results suggest not.
Munoz et al (International Journal of Sports Physiology and Performance, 2014, 9, 265 -272. DOI: 10.1123/ijspp.2012-0350) found “Polarized training can stimulate greater training effects than between-thresholds training in recreational runners."
Neal et al (J Appl Physiol (1985). 2013;114(4):461‐471. doi:10.1152/japplphysiol.00652.2012) found “Six weeks of a polarized training-intensity distribution leads to greater physiological and performance adaptations than a threshold model in trained cyclists”
ok, so I’ll do some low intensity training. But what if I just throw in a few more high intensity sessions? A few is good so more must be better!
Billat (she of 30/30 fame) et al. (Medicine & Science in Sports & Exercise: January 1999 - Volume 31 - Issue 1 - p 156-163) looked at some trained endurance runners and found that they were able to increase running speed at VO2 max with a programme of 4 continuous (easy pace) runs, one high intensity (HIT) session, and one lactate threshold (LT) session. When they changed this and added intensity, with two continuous runs, three HIT sessions and one LT session each week they found no additional adaptive benefit, increased subjective training stress and indicators of overtraining.
All of which tells us that polarised training works for recreational athletes and there’s a limit to how much high intensity work you can and should do.
A typical week
Although the training plan for every athlete should be tailored to their history, goals and progression during the season, here’s a typical week that might result in a polarised 80/20 intensity distribution for a cyclist. The details would be different for a runner, but the principles would be the same. It includes some hard efforts, longer endurance rides and easy recovery days. The hard days are hard and the easy days are easy! It’s a sustainable, effective approach to training that could be repeated over and over, building on fitness gains over time like compound interest building up in your savings account.
What is Sweetspot Training?
Sweetspot means training just below your threshold (FTP). It’s a moderately hard effort that you could sustain for long periods of time. It was popularised by Dr Andy Coggan in his book “Training and Racing with a Power Meter”, which suggests sweetspot strikes a balance between physiological strain and training duration to achieve a maximum training effect.
"sweetspot strikes a balance between physiological strain and training duration to achieve a maximum training effect"
To work in your sweetspot zone, aim for roughly 88-93% of FTP or 85-85% of your threshold heart rate.
Why do Sweetspot Training?
Sweetspot training has a wide range of benefits for your aerobic engine – increases in blood plasma volume, mitochondria, glycogen storage and muscle capillarisation, for example. It’s also an enjoyable level for training where the athlete feels they’ve had a great workout without the mental fatigue of maximal efforts. Don’t discount the value of motivation!
This means sweetspot is a great option for those on a limited time budget, especially during a base phase of the season.
"sweetspot is a great option for those on a limited time budget"
Sweetspot intensity, especially combined with low cadence / high torque work, is also effective in decreasing the amount of energy you produce through an anaerobic glycolytic pathway (referred to as your VLamax). It might seem counterintuitive to want to decrease your energy production, but according to sports scientist Sebastian Weber, your FTP is balance between lactate production and lactate clearance. Reducing your VLamax can, therefore, increase your FTP without changing your VO2max or aerobic capacity. This means sweetspot should be a regular session for steady state athletes like time triallists, triathletes and duathletes. However, sprinters would be advised to stay away from this kind of work, especially close to race season. Finding the delicate balance between VO2max and VLamax has helped shape the training and success of Sebastian Weber’s elite riders like Tony Martin, Peter Sagan and André Greipel.
"sweetspot should be a regular session for time triallists, triathletes and duathletes"
However, sweetspot training will only get you so far. To reach your potential you’ll also need to incorporate other low and high intensity sessions, especially if your event demands include bursts of power like in road racing, criteriums, cyclocross, MTB, track sprinting or draft legal triathlon. Also, for most athletes, two or maybe three sessions a week is enough. Remember sweetspot does have a metabolic cost, so there is a limit to how much you can or should do.
"two or maybe three sessions a week is enough"
How to do it
Sweetspot work can be part of a longer endurance ride or a dedicated session on the road or trainer. Completing sweetspot work on long hills or on the trainer also allows you to get the added benefits of sustained low cadence work.
Sweetspot Hills – Include 2-3 climbs of 15-30 minutes at sweetspot intensity during a ride of 1.5 hours or longer.
Trainer workouts – make sure you bookend these intervals with a suitable warmup and cooldown
Q - Why do you think so many athletes get injured?
Dalia - From my own personal experience of working with athletes, the most common reasons I see for people getting niggles are usually ramps up in training, over training but also sticking to one discipline, i.e. just running and no mobility work/cross training/strength training. I also feel that our general modern lifestyles play a part too. We sit at desks for several hours a day, we then sit in cars or public transport and then we sit again at home. Therefore we don’t spend as much time exercising our range of movement in different ways.
Chris - There are many reasons for injury to strike but increased training load is often a factor. This might be an acute load from a single session or a more chronic issue where total training load over time leads to breakdown. Athletes love their sport and always want to do more. Sometimes the hardest part of coaching is convincing people to do less! If people paid as much attention to their recovery as they do their training then we’d definitely see fewer injuries.
Q - What techniques can athletes use to keep their body in top shape?
Dalia - Cross training is great for athletes! Perhaps there is a weights class you can do at the gym. Not only does this provide you with extra power for your sport, stronger muscles will help injury prevention. Swimming is a great low impact exercise that can help work on our breathing but also a sport that can be done on rest days (we are talking easy here). Range of movement is great for athletes so a yoga class is perfect, it doesn’t have to be high impact either or even an hour long. Sometimes just a 20 minute yoga video in the morning before work is fine. Sleep is really important, something many of us struggle with but it’s important not only for our health but for our performance and recovery.
Chris - I agree that cross training is great advice, particularly for runners. Participation in other sports has been shown to reduce injury risk and can be used to provide aerobic conditioning without the pounding of running. On the flip side, cyclists can suffer from very low bone density unless they supplement their training with activities that place a mechanical load on the skeleton, like running or lifting weights.
Another important issue is diet. Many athletes undereat because they are trying to reduce body fat, thinking that this will improve performance. This can lead to a condition called Relative Energy Deficiency in Sport or RED-S. This is characterised by low-energy availability and low bone mineral density. In women, it typically results in menstrual dysfunction, including loss of period. It may not be as obvious in men, but results in low testosterone and can lead to long term health issues. To stay healthy, athletes need to fuel the work they do!
Q - Athletes love their foam rollers! How should foam rolling be used?
Dalia - I’m not a big fan of foam rolling personally. If I do it then I do it quite lightly. It’s rather superficial and I would just rather have a massage! I get why it can feel good and *feels* like it’s releasing muscle. Most people do it wrong though! People often believe that foam rolling has to be painful but this could be doing more damage than good. Foam roll to level that’s comfortable, like a deep massage. If in pain, muscles could tense up and we put our body through unnecessary stress.
Here are a couple of articles that are worth a look:
What foam rolling is actually doing when it hurts so good
Your IT band is not the enemy but maybe your foam roller is
Q - What advice do you have for self coached athletes?
Chris - Concentrate energy on getting the basics right and be patient. When you start training or increase your training load, your aerobic fitness can increase very quickly. All that exercise capacity is like a new toy that you just want to play with all the time. Ride further! Run faster! Unfortunately, our musculoskeletal system (bones, muscles, cartilage, tendons and ligaments) takes a bit longer to catch up. One possible reason for this is that connective tissue only adapts to the first 5-10 minutes of each activity. As we become capable of training sessions much longer than this we increase the gap between our capacity to do work and our body’s ability to withstand the load. The result is often a disappointing and frustrating battle with injury.
To avoid this, I prefer to work on exercise frequency before extending duration and intensity. Light to moderate exercise 4-6 days a week is a safer way to build fitness than two monster training sessions at the weekend.
There are some popular guidelines out there, like increasing your mileage by no more than 10% a week, but these are far too generic and can quickly lead to a greater load than athletes can handle. Increase your training slowly and then hold at that new volume. See how your body responds and then decide whether it’s safe to add more. Long term development comes from consistency over weeks, months and years so don’t rush it!
Think about your equipment but don’t overcomplicate it - fit and comfort are the most important factors.
For runners, the choice of running shoes can be bewildering. Look online and you’ll get evangelical insistence that there is only one true path to running shoes enlightenment - cushioned, minimalist, barefoot, maximalist! Forget all that and just wear shoes that feel comfortable, rotate through several pairs of different shoes and replace them when they’re worn out. Simple.
For cyclists, a bike fit isn’t just for the pros! A bike fit from an experienced practitioner can help keep you pain free. Something as simple as an incorrectly set seat height has been shown to increase the risk of knee injury.
Finally, don’t wait for injury to strike before you take action. A history of injury is consistently the biggest risk factor for future injury so the best thing you can do is stay injury free to start with!
Q - What should athletes do if they develop a niggle?
Dalia - Don’t google it! Or ask on Facebook! See a physio/medical professional. Very often we feel a pain in our knee and just assume it’s the knee, we may foam roll, book in a massage, google our symptoms, ask on Facebook but my advice is to always see a professional who can take a look at your biomechanics, like a good sports physio. Very often people lack strength in core, glutes and ankles, range of movement is limited, muscles compensate. So whilst you think you may have a knee problem, it could be coming from other areas. With some injuries or niggles rest is advised, others can sometimes benefit from continuing our sports (but steady) and/or loading exercises. A good sports physio can advise you on this.
Chris - Firstly, stop doing things that hurt! A niggle is often the first clear sign that something isn’t right. Next, assess your training leading up to this point. Have you had a particularly hard session? Has your overall training load increased? How about rest and nutrition? Has equipment changed or is it worn out? If a short period of rest or reduced training doesn’t resolve the situation, definitely go and see a professional for advice.
Q - How can a massage therapist help?
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