How To Use A Power Meter – The Complete Guide

How to use a power meter Chris Froome

Many people jump into buying a power meter (which is awesome) but plenty have no actual idea how to use a power meter.

It may seem strange, but in an age where buying the latest and greatest is a constant desire buying something with zero knowledge can still be a bit of an oddball.

If you’re looking for a do-it, know-it all guide then this one’s for you.

Power meter>bike

First things first- your power meter is more important than your bike. Well, sort of. If you’re relatively new to cycling and wanting to take it more seriously, you’re so very wrong if you think that a brand spanking new bike is the answer and the holy grail to superior performance. The term “it’s not about the bike” couldn’t be more true.

If you’re looking to improve your fitness then the number one way, without word of a doubt, is to spend your hard earned dollar on a power meter.

Power meters let us train smart and objectively. The problem with using heart-rate or ‘feel’ is that there are way too many variables such as: water intake, sleep, caffeine, humidity, whether you’re drafting, if you’re ill, if you have high blood pressure or if you’ve drunk alcohol in the past few days. Power is power and heart-rate, well, heart-rate is just unreliable. A major, major problem with using heart rate is that it takes ages to catch up with the power we are actually exerting.

So, we may jump from 200w to 300w instantly but our heart rate will take time to catch up and show that this increase in effort is actually taking place. The only important thing heart-rate does for us is that it shows us how our body is responding to the power we’re putting out.

Power meters are important, sell a kidney if you have to.

That being said, if you’re doing a TT or are in a race and suspect your power meter might be giving you dodgy signals then ignore it all together, this really is where you have to go on ‘feel’ and should be one of the few times you do so (this is more advanced).

Additionally, if you think you can’t afford a power meter, you can. Anyone reading this with internet can afford a power meter.

Shopping around

Over the past few years more and more power meters have come on the market, driving prices down. SRM and PowerTap used to be top dogs but with such a wide array of businesses dipping into the market you can take your pick on what works for you. These are a couple of types of power meters:

  1. Crank based- these power meters have the unit placed on the back of the crank and tend to be very light compared to the rest of the market (e.g. Stages)
  2. Rear hub- the power meter is built into the rear hub, pioneered by PowerTap- this power meter design is fast going out of fashion
  3. Pedal based- think Garmin Vector here, the power meter is built into the pedal, making moving the power meter from bike to bike very easy but limiting you to one type of pedal (in Garmins case, the LOOK Keo pedal)
  4. Crank spider based- these power meters sit in the spider of the crank, they’re typically slightly heavier than crank based power meters (e.g. SRM, Quarq)

I would personally recommend the Stages power meter, they’re relatively low in price, one of the lightest and incredibly easy to both change the battery and move to another bike. Their customer service is also the best I’ve ever experienced, replacing an old meter of mine for free with the brand new updated generation model- no questions asked and no receipt needed. Not to mention Team Sky now ride them, so if Stages are good enough for Froomey I’m sure it’ll do the job for you.

Vector power meter power tap power meter stages power meter

Getting started and how to use a power meter

First things first when getting your power meter, make sure it’s calibrated correctly per the instructions for your given power meter. You should ideally calibrate it before every ride because otherwise the figures can change purely based on the temperature alone.

Once that’s done the next thing to do is to conduct an FTP (Functional Threshold Power) test, which measures the maximum average power you can sustain for one hour of riding. This test is important because it’s what we’ll be basing your training around by using the training zones derived from your FTP. To make things slightly less messy this is measured through doing a 20 minute test so start by throwing your bike onto a turbo trainer or find yourself a nice long stretch of road, preferably flat and definitely with no traffic lights and downhill sections. The process is as follows:

  1. You want to start with a good 15-20 minutes warm up, including some short sprints and some high cadence intervals. When you start the 20 minute test, hit the lap button on your Garmin or cycling computer to make it easier to calculate your FTP later.
  2. The first 5 minutes should be fairly comfortable, you never want to start out too hard or you’re guaranteed to blow up later on.
  3. As you hit the 5 minute mark the next 10 minutes are absolutely crucial, you need to settle into a rhythm that isn’t too hard and isn’t too easy, it should hurt but not so much you want to let out a whimper (not just yet anyway!).
  4. Once you’ve made it to the 15 minute mark you’re nearly home and dry. You’ll be feeling the burn in your legs as the lactate takes its toll but most of all you’ll be feeling the burn in your head. Don’t let the pain get to you and make you slow up, constantly think “it’s only a couple more minutes and I’ll be done”. At this point your mind and thinking is most crucial, because as soon as you lose these your power will drop rapidly and you’ll be itching to climb off the bike.
  5. When you’re into your last minute you want to completely empty the tank, you shouldn’t be able to walk, talk or think about anything except the pain. Ideally you should’ve paced yourself well and shouldn’t have much left by this point but 95% of us will go slightly too easy through the test and have too much energy left for the end. Might as well make the most of it and use every last drop.

To work out your FTP and training zones:

  1. Head to Strava, Trainingpeaks or whichever post-ride analytical website you fancy.
  2. Select the 20 minute period where you conducted the test or view the lap you created. From this you should see your average power over the 20 minutes.
  3. Now, because this was only a 20 minute effort and not 1 hour you need to multiply the average by 0.95. For example, 300 watts x 0.95 would give an FTP of 285.
  4. To find your training zones you have to calculate based on a percentage of your FTP. All 7 training zones can be found below.
  • Level 1 Active Recovery = < 55% of FTP
  • Level 2 Endurance = 56-75% of FTP
  • Level 3 Tempo = 76-90% of FTP
  • Level 4 Lactate Threshold = 91-105% of FTP
  • Level 5 VO2 Max = 106-120% of FTP
  • Level 6 Anaerobic Capacity = 121-150% of FTP
  • Level 7 Neuromuscular Power = maximum effort

FTP test power meter training

Using training zones

Training zones will become an integral part of your training plan if you truly want to increase your performance on the bike. Training in the neuromuscular level for example, will aid in helping to increase your maximum raw sprint power that you can sustain for a handful of seconds. Or if you have a TT you’re targeting and want to boost your FTP then you need to be working in the lactate threshold (or in other words, ‘the sweet spot’). Using a mixture of these helps to develop you as a cyclist as a whole and focusing in on certain levels helps us to build your power for race winning sprints or for the long slogs to glory up mountain passes.

If you’re looking at dialling in your training and using your training zones to get the most out of your cycling then get in touch and we’ll work out a plan to match your goals.

The next (most unproductive) thing to do…

…is checking out how you stack up against the pros and other competitive riders alike! To do this you need to work out your power to weight ratio which is simply how many watts of power you put out for every kilo of body mass. To calculate divide your FTP by your weight in kilograms. For example, 285 divided by 65Kg gives us 4.38 W/Kg. Then check out the image below from to see how you stack up (making sure you look at the 20 min column).

power meter zones and w/kg zones

This leads us on to power to weight ratios as a whole…

Your w/Kg is pretty much the be all and end all for when it comes to getting up the climbs. You pretty much have three options when it comes to improving w/Kg:

  • Increase your power output while keeping your weight constant
  • Keep your power output constant while decreasing your weight
  • Increase your power output while also decreasing your weight.The golden rule with losing weight is that with a drop in weight usually comes hand in hand with a drop in power as there’s a slight decrease in muscle mass. As this happens it’s more important than ever to focus on building your power so you maintain it as the same while still losing a couple of Kg of body fat.

However, the aim should always be on dropping weight and increasing power- this is the where the money’s at. See below for a paragraph from that explains it well:

“As an example of how small changes can make a big difference, Cheyenne Canyon averages an 8 percent grade for 5 kilometers. If a 75kg rider with a max sustainable power of 250 watts loses 2.5kg, or about five pounds, that would cut 38 seconds off this rider’s time. Improving power output by 20 watts without any weight loss cuts 85 seconds. If this rider loses 2.5 kilos and increases power by 20 watts, the improvement jumps to 2:03.

Jump on a high carb- low fat, vegan diet to start shredding the weight and producing more watts!

The greatest pacing tool of them all

Power meters are head and shoulders above anything for pacing and are the number one thing that will help you PR on that Strava segment or win an Alpine stage of the Tour de France. The beautiful thing about power meters is that they don’t lie- power is power.

First, let’s use the example of pacing yourself up a 20 minute long hill to better your current PR. From training and the numerous FTP tests you would’ve carried out over the months from training you will start to become ‘familiar’ with your power and your capabilities. If you have Strava, TrainingPeaks etc. then you can easily find out your best average power for 1 minute, 5 minutes or 20 minutes and so on, this makes it a lot easier to see your capabilities. Even if you don’t use these analytical web apps, you should already know the power you can sustain for 20 minutes (from doing an FTP test), therefore the goal is to never go under or over this figure beyond 5%. This ensures that you don’t go too hard or too easy.

Secondly, if you’re in a race situation going up a climb and you see people start going off the front you can have a good estimation of the power they’ll be putting out. You might be riding a climb at around 350w and see someone attack, you know that the power they’ll be putting down is completely unsustainable for a long duration of time and they will eventually have to slow down and pay for the effort or instead try to set a more comfortable tempo. The key with a power meter is that you can simply just pace yourself at a wattage you know you can sustain and not have any massive spikes in your power. Big spikes in power put our bodies into an anaerobic state which is where we feel the build up and burn of lactate. This is why we often see Chris Froome in the Tour de France just keep a steady tempo even when a close rival has put in a big attack- he knows that if he paces himself with his power meter in all likelihood he’ll catch the rider who attacked and most likely pass him due to Froome’s legs being less fatigued.

Lastly, if you’re planning on doing an EPIC ride, power meters are one of the most helpful things (other than carbs and water!) Similar to using it when you’re climbing, you should be able to work out the maximum power you can sustain for a set duration. This’ll mean you can make sure you don’t go over this number too frequently, which will help to make sure you don’t blow up before your intended target.

Power is king

Power meters are insanely useful, probably the most important thing you can have when it comes to riding your bike. If you truly want to get fit you need one.

Leave a comment with what you want to know about power meters and we’ll answer all your questions!

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.