What are the best Cycling Metrics?
With our ability to track more and more data, it can become easy to get overwhelmed or miss the point. Here Coach Kevin aims to simplify all the noise and keep you focused on some of the primary metrics that make you faster. Read on to find out more.
Let’s start with the basics – a definition. Metrics are “measures of quantitative assessment commonly used for evaluating, comparing, and tracking performance”. For most of us, performance in this context means ‘how well will I do in my next race’? Or even more simply, ‘am I getting faster’? Quantitative means that we can assign a value to it, so not just ‘faster or slower’, for example.
So a useful metric is one which will successfully predict race performance (or answer the question ‘will I be faster’), and will probably be a number.
You could at this point think, well what about speed? That’s pretty much the best metric for answering those two questions – and you would be right – sort of. Speed would be the best measure if you trained each day on your chosen race course. If you happened to have an indoor race track in your back garden and doing five laps as fast as you can was the goal, it would be the only metric you’d really need to look at. In fact, when most people start riding bikes to get fitter / faster / or just more healthy, a lot of them use average speed to indicate whether they are improving. It’s a great place to start, but as soon as you move away from your five laps of the race track, then other factors begin to have an effect. Distance, gradient, road surface, wind strength & direction, how long you can stay aero, etc. will all affect your speed. It’s not hard to see that if your average speed was less on a hilly course versus a flat one, it could still represent a performance increase.
A useful metric will successfully predict (your specific) race performance and won’t be affected by most of those external factors above. Power lends itself very well to this, so all of the metrics that follow will include power to some degree, and our first metric (which will surprise very few of you) will be FTP, a particular measure of power.
FTP
FTP, or Functional Threshold Power, is the maximum power you can maintain for….well, that’s the slightly grey area with FTP. Even the man who coined the phrase, Dr Andrew Coggan, seems to steer clear of a definition of how long, and it’s fuelled debate on cycling & triathlon forums for a very long time. You can see what the man himself has to say about it here. Most people are happy with a duration of 45 - 70 minutes. More importantly, it is an easily measured metric that reflects your maximum (relatively) steady-state power, using mostly aerobic energy sources.
There are a few reasons why this metric is the one that everyone knows about & uses. Firstly – it’s an excellent predictor of cycling performance for durations as short as 4 – 5 mins up to a couple of hours or more. Secondly, it’s pretty easy to measure compared to other methods such as Lactate Threshold, also known as Anaerobic Threshold (which is essentially a different way of measuring the same thing that FTP represents). All you need is access to a power meter or turbo with a power function, and 40 mins or so to do an FTP test.
So if FTP is so useful, why bother with anything else? Well if you are competing in short races such as criteriums, short road races, or sprint triathlons, and prefer to keep things simple, then you might not need to. But some of us compete in longer events, where there are things other than ‘max sustainable power for about 45 – 70 minutes’ can affect race outcome.
Aerobic Threshold
When I mentioned lactate threshold above, there are two lactate thresholds generally defined during testing. The one above (that’s essentially the same as FTP or Anaerobic Threshold) is the second one. The first one happens earlier on (so at a lower power or heart rate) and represents the highest power you can sustain without increasing your lactate levels from baseline. Why is this important? Well, it represents your maximum ‘cruising’ speed, where you are burning the most amount of fat as a fuel (you are likely also using some carbohydrates, but not much). This is important as it represents your ‘long duration’ max power, not your 45 – 60 min max power. If you are well trained enough, you could likely keep this power up for many hours, as we all have substantial fat reserves compared to carbohydrate, and due to the low usage, our carbohydrate stores should be kept topped up. This intensity is the cornerstone of base training and aerobic adaptations.
It’s also not a fixed point – with training, this aerobic threshold can be moved up closer to your FTP, therefore allowing you to push harder for longer. As an example of how it can affect performance, Paula Radcliffe improved her running speed at this threshold from around 14km/h early on in her career to 18km/h ten years later when she broke the women’s world marathon record. Her VO2 max didn’t change at all over this period. This meant that her record-breaking pace was not that much faster than something she was relatively comfortable with.
So what’s the drawback with this metric? Well, even for those people who have been tested to determine this value, unless you are a professional supported by regular physiological tests, it will be difficult to track changes in this metric. Luckily, there is current work on measuring this same point via a different mechanism – heart rate variability (HRV). The scientific methods are still in early days, however, do look promising so that anyone with a heart rate strap and a Garmin device that can record HRV data plus power or pace, will be able to get a good idea of where this threshold lies for them.
Aerobic Decoupling
Another metric that can be useful for the longer distance (or duration) athletes is aerobic decoupling. This term describes the effect when your pace or power diverges from your heart rate. Pace or power indicates the ‘demand’ placed on your body, and heart rate is how well your body is ‘responding’ to that demand. Suppose you’ve ever been out for a very long but steady ride that was perhaps more than you should have agreed to, and the last hour feels really tough without actually being faster. In that case, you’ll know that how your body responds to a particular demand is not always consistent. If a fixed power or pace gives a certain heart rate, but your heart rate starts to creep up after a certain amount of time, the resultant change between the two values is called decoupling. This is given as a percentage value, and a value of 5% or less is considered to represent that you are comfortable with that effort (power or pace), for that duration. This can be very useful not just for those who want to know if they can ‘complete’ a certain distance or race without too much discomfort and as a rough measure of their aerobic threshold. If you can get through a workout of at least an hour or two at a pace where you think your aerobic threshold lies, and achieve an aerobic decoupling result between 3-5%, then this is probably where your aerobic threshold lies. If you get a value higher than this, try a slower pace, or a value below this try going slightly quicker next time. If you have no idea where even to start pace-wise, try either holding your heart rate 30 beats below your Lactate Threshold / FTP heart rate (20 below if you are very aerobically fit already) alternatively try a pace that you can maintain while breathing through your nose.
Normalised Power & VI
Normalised power (NP) is a mathematical model of the average effort you have put into a ride. It’s not the average power - harder efforts take more out of us and a ride that includes a lot of changes in power will feel tougher than a steady ride of the same duration which gives the same average. NP looks to take account of these efforts in a way that the body feels them. In the same way, these varying efforts are not an efficient use of your energy if the goal is to be the fastest from A to B. So with some exceptions like pushing a little harder on the hills or into a headwind, then the closer you can get your NP to your average power, the better you have paced your effort. The difference between those two values is known as the Variability Index (VI). As pacing can significantly affect your times (more so as duration increases), these metrics are worth looking at when you do time trial or race efforts. If you would like to look into this more for a particular race course, then Best Bike Split is an excellent resource.
Hopefully, you can find a metric that works for you, as seeing progression is a big part of what keeps a lot of us motivated to improve. Once you’ve found a metric that makes sense for your event, make sure you track it regularly, keep your measurement methods consistent, and finally, when it comes to race day, assess just how well it does actually predict how you will perform.
A final note – a metric is there to help you, but it’s not the primary goal. Some people can tend to get a little too focused on chasing the numbers. While no doubt improving these metrics will probably make you quicker, they are not the be-all and end-all. You might have improved your FTP for example, but if you go into a longer race than you are accustomed to without any idea of how you will manage your nutrition, it could still well end in disaster! Don’t lose sight of the bigger picture (am I getting faster?) when chasing metrics. Speed always wins races.
Kevin opened a B&B for cyclists in France in 2014, & then a year later decided to start a cycle coaching (level 3) qualification. This was mainly in order to be able to better support his guests (but also to make his own training more effective too). At the B&B he runs the odd training camp for cyclists but mainly offers coaching advice while guiding guests. An engineer by background, he happy diving into all sorts of training data, but also understanding that coaching is about much more than just the numbers!
After being introduced to triathlon by a good friend & then taking part in races for a couple of years he decided that a level 2 coaching course with British Triathlon was the way forward, completing this in 2019.
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