Threshold Explained

The essential physiological asset required to do well in most cycling events is a competitive threshold power to weight ratio coupled with the ability to endure. If you are capable of generating competitive watts at your threshold, you are likely to be a successful rider within your group or at your chosen event.

Competitive Threshold

All competitive cyclists require both muscular and cardiovascular systems capable of delivering such threshold power. This coupled with the ability to endure and an adequate supply of fuel and hydration will allow a rider to complete both long and short distances at a high sustainable competitive pace.

A good performance at threshold, both aerobic and anaerobic, is compulsory for winning a cycling race. Tactics, technical skills, VO2 max and sprinting prowess also matter, but having a competitive threshold power or more importantly a competitive threshold power to weight ratio makes it unlikely that you will get dropped before the finish line or find yourself struggling at a time trial, hill climb or sportive.

The good news is that anaerobic threshold, as well as aerobic threshold for endurance, are highly trainable and we will show you how.


Threshold in detail


The Shift

During low-intensity exercise, blood lactate remains at or near to resting levels. As exercise intensity increases there comes a point where blood lactate levels rise sharply. This signifies a shift from aerobic to anaerobic energy production. Several terms have been used to describe this shift and many coaches and athletes believe it is the same phenomenon. In simple terms, we call it "threshold", however, it is a little more complex. It is also extremely important that you understand the principles as threshold plays a crucial role in both training and pacing during events. 


Aerobic threshold leads to Anaerobic threshold

In exercise zone 3 we progress through aerobic threshold (AeT) to anaerobic threshold (AT), also known as lactate threshold which has been defined as the intensity of effort after which during exercise the body can no longer remove blood lactate at the rate of its production. This results in blood lactate levels building within the active muscles until it is no longer possible for the athlete to maintain the effort. In training, we often talk about FTP (Functional Threshold Power)  ) is the maximum power output an athlete can maintain without reduction for 1 hour.

FTP and LT have become confused to mean the same thing because your maximum effort for 1 hour is commonly almost the same if not a fraction lower than your lactate threshold. Dr. Andy Coggan realized this, so he came up with the FTP concept.

So, to recap: what is the difference between lactate threshold and functional threshold power? LT is the point at which lactate increases in the bloodstream exponentially whereas FTP is the maximum effort an athlete can maintain for 1 hour without reduction.

Lactate or Anaerobic threshold is often referred to as the burn. It’s painful and the onset of anaerobic threshold is the beginning of the end as far as increasing the intensity of effort is concerned. In a graded ramp fitness test, most athletes can only hope to increase the intensity of effort by approximately 15-17% before failure once anaerobic threshold has been reached.

In simple terms below anaerobic threshold lies what we call the aerobic exercise zones (exercise zones 1, 2 & 3) where the body is burning firstly fatty acids and oxygen, and later as the intensity increases carbohydrates and oxygen. In exercise zone 3 as the intensity of exercise increases the aerobic energy systems are gradually replaced by the anaerobic energy systems.  At anaerobic threshold due to the increase in the intensity of effort, the body starts to use more carbohydrates as fuel until only carbohydrates are being used. Oxygen supply at this point cannot now meet the muscles demand to resynthesis fuel or to remove the ever-increasing levels of blood lactate and other waste products produced in by the muscle as a result of the effort.

When we are in the anaerobic zones (exercise zones 4 & above) the giveaway is that your breathing changes from a deep but controlled steady state to panting and later gasping as the intensity increases.

It is also important to note that at these higher intensities of effort you are also using your blood sugar fuel reserves at an accelerated rate, and this will limit the time which you sustain your effort without refuelling. The accumulating lactate acid within the muscle will also induce fatigue which will quickly limit your ability to sustain the effort.

So what’s happening? Extra fuel and oxygen are transported in the blood via the arteries and capillaries which pass between and through each muscle, and the waste products are removed via the veins. However, when a muscle exerts more force the arteries, capillaries and veins become progressively compressed so that it becomes difficult for the blood to bring new energy producing material and remove waste products. Thus the supply of energy material and oxygen, and the removal of waste cannot keep pace with the demand, and the muscle rapidly tires. In short, failure occurs when blood lactate or waste levels are so high within the active muscles that sufficient fuel to sustain effort can no longer be supplied.

Here is an analogy… If we think of the muscle as a piston in an internal combustion engine, we need to think of the cardiovascular system as the carburetor and exhaust system of that engine, supplying fuel as fast as the piston demands and clearing the waste at the same rate to allow further combustion. In this case, the internal combustion engine is starved of fuel and chocked with waste product. A rider’s performance is therefore determined by the training of all the bodies systems in balance, the muscular, respiratory and cardiovascular systems.

As previously mentioned Functional Threshold Power (FTP), another expression for the same phenomenon as anaerobic threshold represents your highest sustainable power output over a 40 to 60 minute period, depending on whether you’re a trained athlete or not, before fatigue affects that output. As you fatigue your heart rate increases to maintain a fixed power output or at a fixed heart rate your power output decreases, we call this drift.


Aerobic Threshold and Anaerobic Threshold

Under increasing intensity of exercise, muscles are delivered increasing quantities of oxygen in order to sustain their metabolic demands and subsequently increasing quantities of waste product are extracted. As long as muscle oxygen delivery matches or is in excess of oxygen demand, then muscle oxygenation levels remain relatively constant. But when demand exceeds delivery the balance will tip, leading to what sports scientists call a 'recordable desaturation event'. At the same time, increased workloads begin to stress cellular aerobic machinery beyond their capacity to produce sufficient energy. This leads to an increased reliance on the anaerobic energy producing systems and increasing lactate production. As soon as production exceeds clearance, the measurable concentration of lactic acid increases. So in a broad sense, we use the term threshold to refer to two different yet equally important physiological events listed below: -

1. Aerobic Threshold in detail

Aerobic threshold is the training intensity which produces the first rise of blood lactate above baseline. This event is sometimes referred to as the ‘breakpoint threshold.’ Aerobic threshold is important in training because it is the level of intensity at which anaerobic energy pathways start to become a significant contributor to energy production. In contrast, intensities below this are predominantly aerobic. Large training volumes at or below this intensity target development of the aerobic energy producing systems. Endurance athletes want to increase their aerobic threshold because doing so will enable them to train and/or race faster for longer before they begin to rely on anaerobic metabolism which cannot be sustained for very long.

2. Anaerobic Threshold in detail

Anaerobic threshold relates closer to the onset of blood lactate accumulation or in other words the transition from “steady” to “rapidly increasing” lactate production. You are said to have crossed anaerobic or lactate threshold when blood lactate concentration increases by at least 1 millimoles per liter in two consecutive stages. In simple terms, it is defined as the level of training intensity at which lactic acid is produced faster than your body can clear it. Exercise at or above this point is meant to train the anaerobic systems.

Anaerobic threshold has historically been one of the great focuses for athletes because of its close relationship with maximum lactate steady state (MLSS) and ultimately race performance. In practice, it refers to the highest workload that can be maintained for an extended period of time (40-60min). It is essentially your body’s redline and is an extremely reliable and powerful predictor of performance in endurance athletes.


Why measure AT/FTP?

Regular AT/FTP testing will allow you to rationally assess whether your training is working and your performance is improving. It will allow you to reassess your training zones and therefore train accurately at the correct intensities to make further desired adaptions.

During a 20 minute FTP test, 95% of the average power can be used to determine FTP.

I prefer to test to assess AT/FTP by using a graded ramp test as I find the protocol controlled pacing makes the test more reliable. 

Lab Quality Fitness Testing and Assessment from 45.00


The 80:20 rule - the secret of better training

Chasing the pack

When I started racing cross-country in Switzerland, I thought that chasing a faster rider would help me catch the pack quickly. My nemeses was a guy called Marcus. My training replicated my racing, it was all top end just like I was chasing an imaginary Marcus. Of course, I couldn’t catch him and as the season went on I began to really dislike poor Marcus, but I quickly realized that I had to train differently, I had to employ a system.

I had heard about the 80:20 rule, the Pareto Principle which states that roughly 80% of the effects come from 20% of the causes.

This principle was named after the Italian economist Vilfredo Pareto who published a paper showing that approximately 80% of the land in Italy was owned by only 20% of the population. Interestingly, Pareto started to develop his theories when he observed that about 20% of the peapods in his garden produced 80% of the peas he harvested!

In fact, the Pareto Principle appears again and again in nature and also in all walks of life from business to crime. For example, 80% of the world’s wealth is controlled by 20% of the population and 80% of crimes are committed by 20% of the criminals. Many natural phenomena have been shown empirically to exhibit the 80/20 rule

Moving to structured training

I began to think about structured training and one of the things that interested me was the 80:20 rule.
An up and coming rider, by the name of Arnaud Rapillard, was working at the Swiss Olympic testing facility in Sion. After one of my tests, he suggested I should spend 80% of my training volume in the aerobic exercise zones and 20% in the anaerobic exercise zones. The Pareto Principle even appears in training systems! Perhaps my training was no exception.

Don’t ignore the basics

We should not ignore some aspects of the training spectrum and concentrate solely on the areas we believe make the biggest gains.

Training is not that simple. It’s a complex relationship that needs to engage all your bodies systems in the correct proportions. Some have suggested that it is possible to short-cut training and concentrate just on the anaerobic 20% that makes the biggest impact. However, without the other aerobic 80%, your training will be incomplete and the all-important anaerobic 20% will be less effective and short lived.
The anaerobic 20% without the aerobic 80% steady state base training work and recovery become 100% which is unstainable. It’s also true that training just in the aerobic 80% area, although improving endurance and the bodies cardiovascular systems, it will not make the necessary gains in speed and force. In short, we have two sides of a coin that need each other to become whole.

As a general rule

A common error in training or riding is that we don’t train or ride in the correct exercise zones for the correct duration to gain the best benefit from our riding or training.

For example, people who perhaps want to lose weight, perform short intense workouts at the gym or those who want to build in extra power and speed perform steady state workouts over long periods. Both do not achieve their aims and the subject is left wondering why all their hard work has not paid back the expected dividends.

Like me, in cycling, a newcomer is often chasing faster riders, but they rarely catch them.

In adopting 80/20 principle, you will target your training in the correct proportions so that you spend the correct percentage of our total training time in the correct areas to maximize gains without inducing over-reaching that can lead to high levels of fatigue and perhaps over-training.

Aerobic and anaerobic exercise

Aerobic exercise

Spend 80% of your exercise regime in the aerobic exercise zones. This will ready yourself for the anaerobic high-intensity part of your training plan. Also, to recover from the anaerobic high-intensity intervals. Aerobic exercise builds the foundation on which to support the improvements in fitness being made (the adaptations). If you exclude aerobic exercise you risk your hard anaerobic work being short lived.
In short, by spending the correct proportion of time in the aerobic exercise zones you are building a foundation on which to build the upper levels of your physical fitness, you are training to train harder.

Anaerobic exercise

We know that massive gains can be made by exercising in the anaerobic exercise zones but because these exercise zones are extremely taxing we cannot usefully sustain these intensities for long.
As a result, we train using intervals, exercising at high intensity placing a high load on both the cardiovascular and musculoskeletal systems of the body repeated for a given number of times. Intervals also include time for adequate recovery at a lower aerobic intensity.

The benefit of this method over traditional long, less intense aerobic work base work such as steady state cycling is that it places a higher adaptation inducing stress on the body without the occurrence of physical exhaustion, due to the longer recovery aspects factored into each workout.

Fitness and strength increases will be achieved more quickly using such high intensity, low volume practices than with long drawn out steady-state exercise.

Therefore, spend 20% of your training regime in the anaerobic exercise zones to make 80% of the required adaptations.

Introducing exercise zones

Physical adaptations take place more quickly in upper exercise zone 3, 4 and 5.

However, hours of steady state training in zone 2 should not be ignored because it readies your body for intense anaerobic interval training.

If time is short, use exercise zone 3 which is often referred to as “tempo” or “the sweet spot”. Tempo rides of around 90 minutes to 2 hours can be very useful in making the same adaptations more quickly. However, like a house, the deeper the foundations the better and to achieve this nothing beats many hours in exercise zone 2.

Also, do not think that if you truly wish to reach your potential you can avoid working in the anaerobic exercise zones. Every zone enables certain, specific adaptations so each has a purpose and should not be ignored.

Important physiological changes occur in zones 4 to 6

Exercise zone 4 and above are the primary targets of interval training to near-maximally load by repeatedly pushing yourself almost to the point of exhaustion. Training at these levels will raise your anaerobic threshold to new heights increasing higher levels of sustainable power and improving your anaerobic capacity.

Positive adaptions are made throughout the muscular, respiratory, nervous and cardiovascular systems that contribute to the production of maximum power by increasing the rate at which carbohydrate utilized, enhancing specific skills such as sprinting, breaking and power climbing.

What happened to Marcus?

Back to the start and poor Marcus. Well, I trained for hours in exercise zone 2 and 3 making 3 to 4 endurance rides a week in the base periods and as I got nearer the season, the intensity increased with climbing in sessions using exercise zone 4, hill intervals in exercise zone 5, and race pace tempo rides in exercise zone 3.

I also raced in the National with Swiss Epic Marathon Series to again build endurance, stamina, skill and yes speed.

The result? I beat Marcus and now when I see someone chasing a stronger rider and working way too hard, it reminds me of this early lesson.

I use the 20/80 rule for the pacing of longer rides, designing training sessions, schedules, and training plans from base to race and have found it to be a cornerstone of balanced training.
Like Arnaud before me, I am also going to suggest to you that 80% of your training volume should be in the aerobic exercise zones and 20% should be in the anaerobic exercise zones.


From the above, you can see that it is not practical, sustainable or complete to just train in the anaerobic or aerobic exercise zones. By adopting the 80/20 rule and working in the all the exercise zones in the correct proportions you will train more completely and effectively. The process will improve all the body’s systems.

With online platforms such as Strava, Training Peaks, etc. it’s easy to record your training and see how much time or, more importantly, what percentage of your total volume of training you are spending in each exercise zone.

It worked for me!


Training fundamentals


Base Work

Base endurance work (exercise zones 2 and 3) is the anchor of your cycling fitness and many hours spent in these lower intensity zones (Between 70 and 80% of your total training) will create a strong base or foundation on which to build. Without this base or foundation, high-intensity adaptions like a house with poor foundations will be short-lived. Although cycling is somewhat specific, exercise zone 2 and 3 aerobic work in other Sports/activities will make the same cardiovascular adaptations when performed in the context of your plan. So at times when riding is not possible off bike work is better than no work. However, it is also important that these off-bike activates are carried out in the correct exercise zones.

Lunge action activities such as Ski touring and hill walking can be particularly useful. Another aspect of off bike work is that it can be useful in correcting some of the postural imbalances created by a season of cycling. However, it is important that as we approach the cycling season more work should be done on the bike.



Aspects of fitness specific to cycling can only be obtained from cycling and if you wish to excel at a particular discipline it is important that you’re training mimics that discipline, climbing improves climbing and flat work improves flat work. Performing an exercise zone 4 session on the flat will use a slightly different muscle group and set of nerves to control those muscles than an exercise zone 4 session on a climb. So if you wanted to be a better cyclist on a climb than on the flat you should perform more sessions whilst climbing than on the flat and vice-versa. Due to the altering ride position, the same will also apply to the type of bike used in your discipline of choice, time trial, road or mountain bike for example.


On the Turbo

The indoor static turbo trainer sessions detailed in chapter 6 are exercise zone specific and once you have practiced them, mastered the principles, and understood their aims, they can easily be adapted to the road, trail or track. The important thing is that you utilise the correct exercise zone intensities, recovery intensities, and durations for each session. The sessions provided in Chapter 6  will help you improve your resistance to fatigue, improve your ability to recover and increase aerobic and anaerobic threshold, improving your sustainable and top end power, along with your overall endurance and race pace.



Work to a Plan 

Within you are given training schedules that range from a simple week training plan, a 6 hour per week training plan through to a 6-month training plan. You can use these examples as templates to help organise your training week to best suit your commitments. Starting with just 3 sessions over the week with some core stability work, in addition, you can make substantial improvements in performance.


Exercise Safely

Before engaging in any of the practices described on this website, please consult your physician or another healthcare professional to determine if these exercises are safe for you. If you feel any abnormal discomfort or other difficulties when engaging in practices described on this website, discontinue at once, and seek the attention of a health professional. If you feel any abnormal discomfort or other difficulties after engaging in the practices outlined in this website seek the attention of a health professional.


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