Training Intensity Domains

Fatbiking in winter forest (Photo by Juho Kuva)
Your body’s physiology is really complicated - luckily, training that physiology doesn’t have to be so intricate. I recently saw a tweet from the coach of 12 time Ironman champion Michael Weiss, which I think sums up how uncomplicated effective training can be:

“Easy, Hard and Long. Learn how to do those properly and they’ll be the only training sessions you’ll ever need to be as good as you’ll ever get.” - Garth Fox

Of course, learning how to execute these sessions properly takes time and discipline. One mistake I see people make over and over again in training, is a lack of intensity discipline. This is when the plan calls for an easy day but for reasons you end up riding harder than you should have. Training like this every day at the same moderately-hard intensity is sure to lead to a decline in performance, stagnation and over-training. For this reason training in this style is often referred to as blackhole training.

In this week's blog post I want to briefly talk about training intensity domains, what intensity domain your easy, long and hard sessions should be made in and give you some different cues that you are exercising in the correct intensity domain and getting the desired response from your training.

Training Intensity Domains

If you were to perform a graded exercise test in a laboratory, three exercise intensity domains defined by physiological thresholds would be visible. These intensity domains are what your training zones are based on and they are useful because when you exercise in a specific domain you can expect a certain physiological response from that exercise.

In the picture above we can see the three intensity domains coloured in green, yellow and red. The extreme intensity domain represents intensities well above your VO2 max like 30 second maximal sprint efforts. We will ignore this intensity domain for now. In the picture I added abbreviations (PK, VK and MK) which are three training zones that most of the Finnish readers will be familiar with. You may also be using another intensity zone model that has more zones. As an example it’s quite common to use a 5 zone training model when training by heart rate. The next picture shows how the 3 zone model is divided into smaller arbitrary zones to get 5 training zones. Next, let's look at the different intensity domains and try to describe how best to execute the training in that specific zone.

This is where your easy and long rides should take place, under the aerobic threshold where blood lactate does not rise above resting levels. It’s quite difficult and time consuming to determine where this threshold is even in a laboratory. So in the field we describe this type of training as
  • Low Intensity
  • Low Perceived Exertion 1-3
  • Talking Pace
  • Comfortable Breathing
  • Low Stress
  • 55-70 % of heart rate max
  • Z1-Z2 55-75% of FTP


If you’re following the training plan some of your hard sessions will be in this intensity domain. Training in this domain should be treated as a high intensity session because these sessions will cost you. They are stressful and require greater recovery time compared to moderate training. In this intensity domain blood lactate levels are elevated above resting levels but are stable, allowing you to exercise at quite a high intensity for a quite a long time. Think 40km cycling time trials, half marathon and marathon events.

There are many different ways to assess your anaerobic threshold or find a close proxy. If you have power you could use a critical power test or FTP. If you are using heart rate you could use 70-80% of your maximum heart rate for an estimate. Training in this domain is characterised as

  • Medium Intensity
  • High Perceived Exertion
  • Short Responses Only
  • Heavy Breathing
  • High Stress
  • 70-80% heart rate max
  • Zone 75-100% of FTP


Your hard training sessions, about 2 out of every 10 sessions that you do should be made in this training intensity domain. Exercise in this domain causes blood lactate levels to rise quickly, breathing rate increases along with oxygen consumption until V02max is attained and shortly after that you will have to stop. Training in this intensity domain typically takes the form of interval training since taking a short rest between these effort will allow you to accumulate more minutes at a higher intensity than you would be able to if you tried to do a continuous ride at the same intensity. The training in this domain is characterised by

  • High Intensity
  • Very High Perceived Exertion 7-8
  • Speechless
  • Breathless (Gasping)
  • Very High Stress
  • 80-100% heart rate max
  • Greater than 100% of FTP

If you found this interesting I’ll leave you with an excellent TED Talk from Dr. Stephen Seiler who is one of the foremost experts on training habits of elite performers:

Training Plan

See below for more details about Easy Day and Hard Day routines.


Monday - Easy Day

  • 60-90 min continuous exercise

Tuesday - Hard Day

  • Session 1: 20-30 min strength training
  • Session 2: 2 x 10 min neuromuscular high torque, low cadence intervals

Wednesday - Rest Day

  • Complete rest or make an easy 20-60 min walk

Thursday - Easy Day

  • 60-90 min continuous exercis

Friday - Easy Day

  • 60-90 min continuous exercise

Saturday - Hard Day

  • Session 1: 30 min strength training
  • Session 2: 2 x 10 min neuromuscular high torque, low cadence intervals

Sunday - Long Day

  • 100-120 min continuous exercise


Monday - Rest Day

  • Complete rest or make an easy 20-60 min walk

Tuesday - Easy Day

  • 60-90 min continuous exercise

Wednesday - Easy Day

  • 60-90 min continuous exercise

Thursday - Rest Day

  • Complete rest or make an easy 20-60 min walk

Friday - Easy Day

  • 60-90 min continuous exercise

Saturday - Easy Day

  • 60-90 min continuous exercise

Sunday - Rest Day

  • Complete rest or make an easy 20-60 min walk

The Training Sessions

Easy & Long Sessions (marked with green color)

These continuous slow long distance sessions typically range from 1-6 hours in duration and are made at an intensity where breathing feels comfortable and you are able to carry on a conversation without much effort.

If you’re on the bike try to maintain a cadence between 90-115 cadence throughout the session. If you’re doing a session 90 min or longer you could add 4-5 X 15 seconds cadence sprints where you spin an easy gear at maximum leg speed for a full 15 seconds.

It’s not absolutely necessary to train exclusively with the bike. If you prefer to run, cross country ski, snowshoe, swim or row I would recommend spending your training hours doing something you enjoy..

Hard - Interval Training (marked with orange color)

In week 3, high torque, low cadence intervals are back with the purpose of improving your neuromuscular system. Start with a 20-30 minute warm up. Then do 2 X 10 minute intervals in a big heavy gear that you can just turn over at 40-60 rpm. Rest 10 min between efforts and use an easy gear that you can spin at a cadence of at least 90 rpm. These are not maximal efforts, you should not have to lay down after them but they should feel somewhat hard while you are doing them.

If you’re not on the bicycle you could turn this into running hills/stair repeats. Or you could do 3 X 8 minutes hard in any other exercise modality. With up to 8 min recovery between efforts.

Hard Days - Strength Training (marked with orange color)

Core and body conditioning will make you a more robust rider and strength training has been used to increase both short and long duration endurance capacity. If you’re new to strength training give this session a try.

Warm Up - Dynamic Stretching 6 exercises 1 set 8 reps

  1. Prisoner Stand Ups
  2. Down Dog with Toe Touch
  3. Cat-Camels
  4. Kneeling thoracic rotations
  5. Down Dog to Runner's Lunge
  6. Glute Raises-Fire Hydrants

Block A – Strength Training: 3 exercises 1 set 8 reps (each side)

  1. Back Leg Elevated Single Leg Romanian Deadlift
  2. Skater Squat (you can hold on to something)
  3. Split Squat

Block B – Strength Training: 3 exercises 1 set 8 reps (each side)

  1. Tall Kneeling Press Up
  2. Single Arm 1.5 Floor Press
  3. Single Arm DB Row Off Floor

Block C – Core Training 3 exercises 1 set 6 reps (each side)

  1. Deadbugs
  2. Forward Off Knee Crawls
  3. Half kneeling Side Plank Hip Lifts
  4. Side Plank Half Kneeling

All the movements for this strength training session can be found here:

That’s it for this one, I will be back in a couple weeks to talk about another training topic and give you another two weeks of training.