In my previous blogs, we have looked at the Big Hairy Goals and THE ART OF Periodisation.  

If you have followed those articles you may know what your BHG is and your LHGs are and different methods of structuring your programme, but how do you decide what the content of those macro, meso, micro-cycles will be?  

For that, you need to know what you require to achieve your desired goals.  Obviously, lots of elements interact to affect bike performance, such as aerodynamics, equipment, nutrition, motivation, health etc, but for the purposes of this blog, we are looking at the physical characteristics required.  Specifically, your performance profile and how that can help to build your training programme.  

Today we are looking at the profiling of BIKE performance.  In order to know what your strengths and weaknesses are though you need to have an understanding of what the requirements of your event are.  It’s no use developing FTP if your goal is an Ironman and your fatigue resistance is poor, for example. 

We conduct a similar analysis for running, but there is generally less data and less objective means of assessing it.  Check out our follow up article which will look at how we use the STRYD for the performance profile.  

What I will be covering: 



For the physical side of the performance profile, you need some quantifiable data. You need to understand what factors influence or contribute to your performance, then you need a reliable means of quantifying them.  At this stage, you can start to determine what the important factors for you are, where your strengths and weaknesses lie and finally how to go about setting your training to make the most of them. 

The diagram above is from Tim Cusick | WKO and illustrates the complexity of various factors contributing to performance.  There will be differences in terminology, and others will represent this in another way, the point is to show though, that performance is not simple!

Endurance performance (from a physiological perspective) is made up of 3 principal areas: 

  • Your ceiling – Max Power and VO2max  
  • How much of that you can sustain for the duration of your event – Fractional Utilisation or Sustainable Percentage 
  • How efficient you are – Efficiency.

Fig 1. A representation of Fractional Utilisation related to triathlon performance

Contributing to these primary areas are many other variables that will impact upon theseWe do not very often talk about the primary 3 factors, because we tend to break them down into more areas, for instance: 

  • FTP or lactate threshold 2 (LT2)  
  • Lactate threshold 1 (LT1) 
  • Fat/carb utilisation 
  • Fatigue resistance 
  • Functional Reserve Capacity (FRC) 

All of the contributory factors will vary between athletes, and the interaction of them will influence the performance.  Athletes racing over longer or shorter events will require a different balance of these variables, and athletes who perform the same, may reach this performance with different profiles and therefore the areas they need to work on are different too.  


Novice triathlete but well-trained athlete from a swim background, but without any significant bike or run training 

VO2max is good, so they have the potential to perform well, but compared with an athlete with similar potential, but who has been training for some time they will be slower 

Due to the lack of specific training, their sustainable percentage will be lower, and their efficiency is likely to be less as they have not performed countless pedal revolutions and built the specific muscle recruitment that will lead to greater efficiency. 

Therefore, we test to find out where the gaps are in the profile and understand what can be improved. This helps us to set the training to address those issues.  

This enables us to be more focussed and waste less time with training and have confidence that the programme we are doing is working, or if it is not, we can determine where it is going wrong.  


There are SO many ways of bike testing. Every platform (Zwift, Trainer Road, Xert, etc) has their own tests, physiology labs all have different methods and scientists cannot agree what to use, coaches use different methods based on experience and/or some science. 

How as an athlete are you supposed to know what is right?

The simple answer is, there is not one RIGHT answer. Like most things in life, it is all different shades of grey. However, there are better answers, and there are wrong ones. 

Lets start with a good motto….

  • The simpler the test the less accurate it will likely be 

There are two main forms of testing, FIELD TESTS and LAB TESTS, there is a 3rd which combines both the FIELD and LAB, but that is more research focussed 

Another way to look at them is there are PERFORMANCE TRIALS and there are DIAGNOSTIC tests. A performance trial is usually a maximal steady state effort of a specific duration.  Diagnostic tests, usually use a range of intensities and measure what happens to the body as the intensity changes. Most field tests are PERFORMANCE trials, and most lab tests are diagnostic. Some labs will do Performance trials in a lab setting.   


Field testing is performed in the real world on your equipment and uses easy to conduct tests 

One of the best-known tests is the 20min all out, which aims to identify Functional Threshold Power (FTP) You take 95% of the power for the test and that is your FTP.  

It works for about 50% of the population. So, for 50% it does not 

How do you know if you are in the 50% it does work for? 🤷Don’t ask me! 

It also only gives you one piece of information, which may or may not be the most relevant to you.  Platforms like Zwift use FTP to categorise riders, but they are not in the business of developing performance, so they only require FTP.  

There are ways of improving the accuracy of the 20min test, by performing a preload effort, but remember what I said about complicated? Yep, you must start adding things to it, and still, you only have one piece of the jigsaw.  

A lot of coaches and athletes only test for FTP and base all their training and planning on this. This is a huge error, in my opinion 

The slightly more extensive but not too complicated version is to perform some CRITICAL POWER trials.  As usual, there is no one correct protocol, but you need to perform a short max time trial effort that is paced evenly (3 – 5-min) then on another ride, perform a longer 12 – 20-min effort, some protocols will add a 3rd or even 4th effort to improve the accuracy of the model 

There are a variety of online calculators you can enter your data into, and it will pop out an FTP figure.  Software like Golden Cheetah or Todays Plan will do this for you as well 

The ADVANTAGE is that you get more information, such as Watt Prime (W’) which is a measure of your anaerobic capacity, and you can calculate an estimated Power at VO2max 

This is useful in identifying some key strengths and weaknesses, and you can use the information to tailor intervals specifically to your profile 

It is easy to organise (it is painful to do though), can be performed on the road (if you are able to control power well) or on your trainer 

Fig 2 Critical power representations. 


Another more extensive version of this is to use WKO5, Training Peaks’ software analysis tool and their test protocols.  This takes critical power a stage further and uses some proprietary terms and algorithm to identify even more metrics.

Fig 3. Left is a modelled Power Duration Curve (PDC), with anaerobic and aerobic contributions. To the right is the actual power against modelled.

Initially, this requires more maximal tests:  a max sprint, 1min, 5 min and 20 – 30min effort.  Using this tool allows us to keep an ‘eye’ on your PDC (Performance Duration Curve) and when holes start to appear we can re-test those holes, feeding the model so we do not need to test the full set too often.

Fig 4. This chart enables us to see where the ‘holes’ are in a power duration curve.

Downsides are it’s hard to get set up, as it is designed for coaches, and athletes with a good knowledge of science and training.  I have seen some horrendous conclusions made from poor data because the user does not fully understand what they are doing.


Physiology lab tests come in different shapes and sizes, levels of experience and levels of accuracy. This last point is truly relevant. In my experience, I have seen some seriously poor reports, and tests performed, and therefore the information the athlete is basing their training off is extremely poor too. If you go this route, go somewhere REPUTABLE.

One reason for going to a physiology lab is that you want KNOW the values for your variables not calculate them and you may be able to understand more about HOW you achieve the performances you do. Field testing must make calculations about some of these, as there is no direct measurement.

In a lab you will usually have some form of gas analysis (see above with the rider wearing a mask to capture the expired gasses).  This samples the air expired and works out how much O2 is being used at the intensity the rider is performing. This then enables the physiologist to understand things like oxygen required at submaximal intensities and, if the test is to max, VO2max, and efficiency.

They may also look at fat and carb use and some might calculate LT1 and LT2/FTP from the gas data.

You will also no doubt get some blood samples taken, to look at the concentration of lactate in your blood at a given intensity – this is turn indicates the level of acidity.


……it is produced when you use carbohydrate as a fuel. At low exercise intensities, it is cleared as fast as it is produced, but at higher intensities carbohydrate requirements increase and therefore lactate accumulates as it cannot be cleared at the rate it is being produced.    It is used as a marker for Lactate Threshold 1 where it first starts to rise (carbs are starting to be used in greater quantity), and for FTP/LT2 where it starts to rise steeply during an incremental test (carbs are exclusively used to fuel the workload).

Where it gets controversial and scientists don’t agree with each other is how to ‘pick’ the threshold.  There are various methods and protocols that have been ‘validated’ but the reality is most of this is educated guesswork.  I’m probably going to take a bit of flak for that, but it’s true.  There are so many methods and terms for what most would consider the 2nd threshold that they clearly cannot all be correct.

Personally, I would use a well-respected lab that is used to working with athletes who operate in the real world, not just the research world.

Fig. 5  Representation of oxygen uptake, blood lactate response, heart rate response, and fat oxidization use to increasing power output, with LT1, LT2, Fatmax and VO2max. 


FAST RAMP (test lasts ~ 7 – 15min) The resistance starts low and builds very quickly to the point you cannot maintain it. Main use is to get a VO2max/power at VO2max.  Some labs try to use this to predict thresholds, but in my experience, this will inflate the value as the ramp is too fast.

INCREMENTAL TESTS – longer usually 20– 60min with stages of 3 – 6min in duration. Starts easy and will increase ~ 10 – 30w per stage, depending upon weight and level. Bigger, more powerful riders will have a wider range of power. Used to establish Lactate Threshold 1 and 2(LT1 & 2), can be used for fuel utilisation (fat and carb requirements), efficiency.  Some labs will continue this until exhaustion and use that to identify VO2max.

Fig 6. Representation of how step tests and ramp test work. 


The argument about stage length is long and boring. In my experience, anything less than 4min tends to overestimate FTP in the real world, although there are plenty of studies that say otherwise. I prefer to take a little more time, be more accurate and assess the characteristics that endurance athletes require.

If you are interested in fuel utilisation rates then the stages do need to be long enough for your physiological responses to fully stabilise at each intensity, and you need enough stages to get good data at a range of intensities. One variable that can be calculated from such a test is FatMax, which is the highest rate that you can burn fats and the work rate at which this occurs. For long-distance athletes, this is far more significant than FTP.

FatMax is not the same at LT1!

Knowing whether you are a good fat burner or conversely a carb ‘muncher’ can heavily influence a programme. A carb muncher is someone who requires carbs at extremely high rates, so high in fact that even at low intensities they are depleting their carb stores, and at a rate that is too high to replace effectively.

Fig 5. Graphical representation of carb and fat requirements as exercise intensity increases.  On the left is a god fat-adapted athlete, on the right a ‘carb muncher’


In a long event they might feel the intensity is comfortable, have a good strategy, consuming 70-90g of carbs an hour, yet still fatigue prematurely. This is because they are using significantly more carbs than they can replace even at this comfortable intensity.

Each gram of fat burnt (or combusted) produces ~ 9kcal, each gram of carbs produces ~4kcal.   At a given work rate there will be a calorific requirement. How the athlete meets that depends upon their physiology and fitness.  A well fat-adapted athlete can use large amounts of fat as a fuel at a quite high intensity (left), where their rate might be as high as 1.1 – 1.2g/min (~600kcal per hr) and occur at an intensity quite close to FTP.  A poorly fat-adapted athlete might have a peak rate of 0.2 – 0.4g/min (~150kcal per hr), occurring at a low intensity which might be below LT1.  It is also possible to be a poor fat burner but have that rate occur at a moderate intensity between LT1 and LT2.

The key points are to know the peak rate of fat burning, AND the intensity it occurs at in order to make informed training decisions.

Its also important to note that whether carb muncher or fat burner you do still use carbs, and you must be replacing them during long endurance events/training.

I have seen very well fat-adapted athletes who are fairly modest performers (lower mid-field in races) and I have seen terribly fat-adapted athletes perform well in races, as long as the event is short enough and their fuel strategy ensures an adequate supply of carbs.

For long-distance athletes, this is my main requirement from lab testing.  With the tools we have in field testing we know most of what we need to uncover, but this cannot be known from just power data (yet).

A weakness in most lab testing I have seen is that the focus is around identifying threshold, fuel utilisation and VO2max, but these metrics are sometimes only a part of the story.  There is actually still a fair amount of very useful information missing that coaches could and should use.  There is no information on anaerobic contribution and there is no fatigue resistance measures.  We all know someone who has a decent FTP but who cannot ride much harder even at full gas, and we all know the opposite person, who has a low FTP  but who can lay down a lot of power for a few minutes then burn out.  Indirectly you can use lab tests to make inferences about this information, but not many quantify it.

Another common misconception is that FTP (LT2 is very similar but technically not quite the same thing) is your ‘hour power’.  THIS IS NOT THE CASE. Even the original research doesn’t suggest this.  FTP is a power you can sustain for 40 – 70-min, some athletes with great fatigue resistance will be able to go longer and others with poor fatigue resistance will be stuck at 40min.  Knowing where you sit on this scale is an important part of knowing your profile and therefore strengths and weaknesses.


WKO5 is our choice of tools for field testing.  It also adds a lot more in terms of analysis of session, and historical training load monitoring etc, but that is a story for another day.

There are a lot of things we can test for and some are discipline-specific. As part of field testing on a regular basis this is what we look for by using WKO and the suggested profile tests.

The basics:

  • Maximum power (Pmax)
  • Functional Reserve Capacity (FRC)
  • VO2max and Power at VO2max (pVO2max)
  • FTP
  • FTP to VO2max relationship (FTP/VO2max)
  • Time to exhaustion at FTP (TTE)
  • Stamina

This provides a lot of information about where an athlete’s strengths and weaknesses are. One of the key one is the relationship of FTP to pVO2max. If this is a low percentage, then the limitation is FTP, if it is a high percentage then VO2max is the limitation.

FRC helps to determine how much work an athlete can do above FTP and is vital in designing sessions that require a power output > FTP.

TTE (Time to exhaustion) tells us whether the athlete’s resilience at FTP is good or not.

Stamina looks at how well they can hold high power below FTP for longer durations.

More advanced:

  • VLamax – lactate building rate
  • Glycolytic Capacity –
  • Fatigue Resistance Metrics
  • Power at 150bpm
  • Neuromuscular characteristics such as torque profile and optimal cadence

These provide a more detailed and specific insight into an athlete’s profile, but not all of these will be relevant or important for all athletes.

I will usually use the lab to look at specific things such as fuel utilisation, and some heat preparation work, but that’s also another story.

Fig 7. I appreciate you can’t read this, but its an example of a dashboard used in monitoring an athlete’s performance profile. 


Testing performance and keeping a regular record of performance is important so that as coaches we can ensure we are developing an athlete’s performance the way we want it to.

I have lost count of the times I have heard athletes tell me of a session they have done and believe it means they can produce a certain time in race, only for them to get nowhere near it.  Fundamentally they are misinterpreting a session to represent a performance test. It is not, it is a training session.

The best test of performance is PERFORMANCE, but that alone doesn’t tell you how you achieved that performance. Specifically targeted testing leads to ENLIGHTENMENT.

Next up I will take you through a couple of athletes’ data, looking at specific results and the rationale for the training programme and its effects.


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