Race training with a power meter – race your fastest ever triathlon with our guide to tri training with a cycling power meter
Training with a bike power meter can make a huge difference to your triathlon performance. Here, with the help of triathlon coaching legend Joe Friel, we’ll tell you how a power meter works, what all the baffling terminology actually means and how to train better with your new power meter.
It’s an amazing training tool, but a power meter alone can’t turn you into a bike-course record holder overnight. The crucial element to a good bike split is always the engine – and that’s you.
What a power meter can do is help you focus your training for maximum gains, keep tabs on fitness improvements and make your training sessions and race pacing scientific, rather than emotional.
Put in the work with your power meter and you’ll soon earn a new PB at any triathlon distance.
Read on to find out how to get the most out of training with power and don’t forget to check out our other bike training content on TriRadar to get an edge on the competition.
Why Train With A Power Meter?
HOW DOES POWER WORK?
Power meters come in a variety of different designs: such as Quarq, SRM and Rotor’s chainset models, Garmin’s Vector pedals, Stages’ unique single crankarm set-up and PowerTap’s wheel hub based solutions.
Whichever you go for, the power meter will output your work in watts, based on the force you’re putting through the drivechain and the cadence at which you’re doing this. You’ll also need to be wearing your heart-rate strap when training with power to get the most out of it.
But why train with power at all? Training Peaks co-founder and triathlon coaching legend Joe Friel says, “While heart-rate (HR) tells you the input (effort) of your workout, power tells you the output (what you accomplished). Knowing both allows you to draw conclusions about fitness. If power rises at the same HR you are more fit. Or, if HR decreases at the same power you are likewise more fit.”
It’s this dynamic then, which is the key to training with power and one that will help you gain a much deeper understanding of your fitness and progress.
One safety note: it’s easy to become entranced by the changing watts on your screen and lose sense of your surroundings – an occasional glance is all that’s needed to see your power and stay safe.
SPEED, DISTANCE OR TIME?
Many triathletes judge their fitness in miles per hour or by distance covered, but using either approach can be flawed.
The former is affected by variables such as wind conditions, temperature and road surfaces, while the latter means different intensities to each athlete, as Friel explains. “While either time or distance can be used, basing a workout on distance doesn’t produce the same type of workout across the board for a wide range of athletes.
“This is easier to explain with running but works the same way for cycling. An elite triathlete’s best 10k time may be 30 minutes while an age-grouper’s best may be 60 minutes.
“Telling them to both train at 10k pace produces gigantically different intensities by zone and calls on entirely different energy systems. So the workouts are not similar although distance may have been the same. But if both are told to run at the speed they can maintain for 30 minutes, the physiological stress is exactly the same.”
Power Meter Terminology
Just as important as the riding itself is interpreting the data that your head unit records from the power meter.
There’s a baffling amount of information on offer, but understanding and watching for changes in these key terms can unlock your potential and help give you an insight into what a powerful training tool your power meter is.
FUNCTIONAL THRESHOLD POWER
Your FTP figure is the most important number in your bike training arsenal and represents the flat-out aerobic power you can sustain for an hour.
“Much of what you learn from the power meter (and its data analysis) is based on FTP. If one doesn’t have an accurate FTP then a lot of the data is questionable,” says Friel.
Indeed, FTP is used to set your training zones and is the figure against which you can plan your pacing strategy, while a rising FTP indicates increasing fitness. You’ll need to test yourself regularly to accurately prescribe your training and check for improvements.
This is a simple procedure, says Friel. “Just complete a 30-minute time trial ALONE and that is a good proxy for your functional threshold power (FTP) — the average power you could maintain for an hour if you were in a race.
“People tend to go easier in workouts than in races. That’s why a 30-minute solo effort is a close equivalent
of a 60-minute race.”
It’s important to pace the effort evenly rather than going easy and getting harder or starting hard and petering off.
Be careful if completing this test on the open road, where there are more dangers and variables to contest with.
If you’re going to perform the test on an indoor trainer, make sure you’ve got a fan and plenty of ventilation as a hot indoor environment can heighten your heart rate.
Working Out Power Zones
Your FTP number allows calculation of your zones. This model devised by power guru Dr Andrew Coggan is the most widely used and is calculated automatically by most training software:
● Z1 (active recovery) up to 55% of FTP
● Z2 (aerobic endurance) 56-75% of FTP
● Z3 (tempo) 76-90% of FTP
● Z4 (lactate threshold) 91-105% of FTP
● Z5 (VO2 max) 106-120% of FTP
● Z6 (anaerobic capacity) 121-150% of FTP
● Z7 (sprint power) more than 150% of FTP
Triathlons are about steady power output with as little variation as possible, rather than the explosive power needed for sprints, so the majority of triathlon bike training doesn’t need to go beyond Zone 4 unless you’re training for a severely hilly course.
What you’re looking for: a steadily growing FTP throughout training.
LACTATE HEART RATE
The same FTP test can also be used to set your heart-rate zones. This isn’t based on your maximum heart rate, but on aerobic effort. You’ll need to know the average heart rate for the final 20 minutes of your FTP test, which is usually found via a straightforward click and drag affair on the power/heart rate graph of the ride in your training software.
This figure is a good gauge of your lactate heart rate, and can be extrapolated into the following zones:
● Z1 up to 81%
● Z2 81-89 %
● Z3 90-93%
● Z4 94-99%
● Z5 above 100%
Normalised power (NP) takes into account the variability in power over different terrains and intensities – there’s no power when freewheeling down a hill and greater power when sprinting uphill for example.
Average power won’t show this but NP does, making it the best gauge of comparable power output over a ride.
You’re looking for: increases in NP over time for similar duration rides.
Intensity factor (IF) is your average power divided by your FTP. Knowing the percentage of FTP for a ride gives you an idea of how hard you rode compared to your maximum output. This figure is key for judging effort in races.
As a guide, Ironman should be ridden at an IF of 0.6-0.7 (60-70 per cent of FTP); Ironman 70.3 at an IF or around 0.7-0.79; and Olympic and sprint-distance races at IF of 0.9-1.05 – the lower intensity evening out the longer bike and run distances for long-course events.
You can fine-tune your own intensity by experimenting with race simulations or B-races. Training at the correct IF for your race prepares you for the rigours of your event, while keeping an eye on this range of watts during your race helps avoid going too hard or taking things too easy.
You’re looking for: IF values reflecting your race-day effort on endurance and simulation rides.
Power Meter Terminology – Part 2
Variability index (VI) is your normalised power divided by average power. By comparing these figures, VI indicates how steadily you’ve paced your ride. If you rode inefficiently, the number is higher. Triathlon is all about judging effort and steady riding, so keeping the figure low will help avoid overexertion. Powering up hills, sprinting or going too hard out of T1 will all affect this.
You’re looking for: VI of up to 1.05 after steady endurance rides.
If your heart rate rises over a ride for a given power, or power drops off while maintaining a certain intensity, decoupling reflects this. As your fitness increases and your aerobic system is able to sustain efforts for longer, decoupling reduces. You can also look at ride graphs showing power and heart rate, to judge your current duration before severe decoupling – then work on gradually pushing this duration out.
You’re looking for: decoupling of around five per cent in race-like endurance rides.
Like decoupling, efficiency factor (EF) compares heart rate and power (NP in this case) to give a score reflecting the overall efficiency of your riding. The higher the score, the fitter and more powerful you are. As such, EF is a good overall training score for your current fitness. If the score drops, this could be due to acute fatigue or overtraining.
You’re looking for: steadily increasing EF throughout training.
TRAINING STRESS SCORE
TSS takes into account duration, NP, IF and FTP to give a score of how stressful on the body a session was. Logging how much training stress you can handle over the weeks helps work out when a break is needed.
You’re looking for: the ability to cope with higher TSS without becoming too fatigued.
The power curve shows your maximum power outputs for each duration along the X-axis and is a useful tool in assessing where improvements can be made over different race durations. High-level sprint power is less important for triathlon riding, but you’ll be able to see improvements at the duration you’ll be tackling on race-day whatever your race distance.
You’re looking for: higher powers for expected race-day bike time.
WATTS PER KG
Keeping a log of Watts/kg can help you find the point at which your maximum fitness and strength tallies with your lowest weight. This avoids losing so much weight that you lose power on the bike.
You’re looking for: higher power for lower weight – a higher Watt/kg score.
Training With Power
As you work towards your most important event of the year, power can help you get to the start line in the best possible fitness.
Just as with any traditional training regime, power-based training is split into base and build periods.
Your power meter won’t do the work for you though – whatever triathlon distance you’re competing at, there’s no substitute for hard work and consistent training.
Build Your Fitness Base
The base period is the time to build your general fitness to as high a point as possible before addressing the specific demands of your race. Here are the sessions to get you in great shape.
The key to performing well in tri is to boost your aerobic endurance as much as possible – your fitness when riding steadily and staying inside your aerobic limits.
The length of time you’ll need to ride for these sessions varies based on the types of races you’ll be focusing on. As a guide, you should be trying to build towards: 50-60 minutes for sprint triathlon; 1hr 15mins to 1hr 45mins for Olympic distance; 2hrs 30mins to 3hrs 15mins for Ironman 70.3; and 4hrs to 7hrs for Ironman.
Of course, this also depends on the terrain you’re expecting on race day.
To test improvements in aerobic endurance, you’ll need to plan a route that you’ll be happy to use time after time and ideally, one that’s a fair approximation of your race course.
Rather than judging by power, ride the route in heart rate Z2, trying to pace evenly. You’ll need to ride the route regularly to build a log of useful data, checking your ride stats after each session for improvements in EF (efficiency factor), NP (normalised power) and decoupling.
This is also an opportunity to hone your ability to pace – shown by your VI (variability index).
As your fitness increases, you should see EF and NP numbers growing and decoupling lessening.
Track the trajectory of these figures over the weeks – once the improvements start to level out, your base fitness is likely to have reached its peak for the duration of the ride – so you’re ready to move on to your race-specific build sessions.
Other base sessions
You can complement your aerobic endurance training with high cadence drills to improve pedalling efficiency and big gear force reps to build strength – be careful with the latter though, as huge stress is put on the joints. Stick to a maximum of 12 reps per leg and take plenty of rest between sets.
● Muscular endurance
Once aerobic endurance is building nicely and beginning to stabilise, you can really focus on what training with power is all about – raising your functional threshold power (FTP). Andrew Coggan pioneered the concept of the sweet spot – a small training zone at 88 to 93 per cent of your FTP that’s just right for building FTP without causing undue fatigue and long recovery times afterwards.
Once you’ve worked those figures out, create an interval workout for yourself, starting with 8x4mins with 1min recoveries and building to 2x20mins with 5min recoveries.
You’ll need to regularly re-test your FTP to check the sessions you are doing are improving your power and fitness. If, as it should, your FTP has grown, update your power zones to ensure you’re getting the most benefit out of your training.
After working on the above key sessions for several weeks, you should see your fitness and FTP building. As you move closer towards your A race, typically in the final 12 weeks leading up to it, you’ll need to realign your training to prepare you for the specifics of race day in the build period.
Practising the pacing strategies in training that you’ll use in your race is key during the build phase. Plan yourself a route that resembles the race course as closely as possible, especially bearing in mind the number and severity of hills – again, you’ll need to be able to use this route regularly to limit variables as much as possible, so make sure it’s one you enjoy.
Ride the route at the IF you’ll be looking to sustain on race day. For shorter distances, this will be a hard session pushing you to the top of your aerobic capabilities. For Ironman athletes, who are racing at around 60 per cent of FTP, it’s likely to feel too easy, but persevere – holding back on the bike is what will allow you to run well and having a power meter gives you the information to keep your emotions in check.
Friel says, “In a non-drafting triathlon, the VI should be no greater than 1.05. Going significantly above that means a lot of excess energy is being used due to the cost of acceleration. This is likely to result in much greater fatigue by the end of the bike leg.”
Use your route to practise your pacing and effort, running off the bike at race pace to get used to the transition and fatigue.
Other build sessions
You’ll also need to tailor the rest of your build training to suit your race distance. If your race is a short, high intensity effort, it’s a good idea to do another session at a lower intensity (power Z2) to maintain aerobic endurance. Conversely, if you’re racing Ironman, adding in interval sessions (such as 5x8mins Z4 with 2mins recoveries) helps keep your strength and power topped up. You should also maintain your sweet spot sessions to continue your fitness and FTP progression, increasing the number of intervals compared to the base period.
Hill Climbs and Power
Even a small incline can send your power spiking upwards, causing you to break out of your prescribed power and threatening your pacing. Do this too much and you’ll compromise the latter stages of the ride and your run.
Friel says, “During a triathlon one’s power output on a hill should climb no higher than two power zones. If riding at 70 per cent of FTP, that would be Zone 2. Two zones higher would mean climbing a hill at no greater than Zone 4.
“Increasing power slightly on an uphill (and decreasing it on the downhill side) has been shown in research to improve performance on a hilly course as compared with maintaining one’s flat-portion power on uphills and downhills throughout the race.”
This is partly down to the speed per watt benefit being greater uphill due to the efficiency of maintaining momentum against gravity and lower drag at slower speeds.
Conversely, going hard on fast downhills creates huge energy expenditure for little speed gain due to increased drag.
You can add in hill-rep sessions to fine-tune your pacing on ascents and build climbing fitness – find hills that match your course if possible and have plenty of rest between reps.
Keep an eye on your power and try to learn as much from the numbers as possible – including how many times your can sustain the climb before accumulating race-breaking fatigue.
Race Practice and Tapering
Race practice or simulation is when you pull together everything you’ve learnt and put it to the test.
Using a B race to test your plans offers a wealth of information, all within a competitive environment. You’ll have to ignore people flying past you at the start of the bike and stick to your IF. This takes spades of mental strength, but by the run you’ll be patting yourself – and all those you’re passing – on the back.
You can also use a race simulation day, transitioning quickly from one sport to another on routes you’ve set to mirror your race.
If you’re doing longer distances, a metric race (such as a 1.2km swim, 56km bike and 13km run for half-iron distance) can avoid overdoing it. Try to make the day as race-like as possible including variables such as nutrition, time of day and transition time.
After the race or simulation, you can assess how you performed. If all’s gone to plan, your VI will be under 1.05, showing how you expertly paced the event, and your NP will be right on the money for the IF zone you’ve set yourself, taking into account the hills you’ve had to scale. You should also know how easy it was to run afterwards.
If your simulation doesn’t go to plan, try to analyse why. Is your VI too high, signalling you might have gone too hard in places? Was your decoupling too great, suggesting too high an intensity or lack of fitness? Was your TSS off the scale before the session, meaning you weren’t well rested enough during it?
Good or bad, all this information helps you to tweak your race plan towards the most efficient performance possible.
TAPERING FOR YOUR TRIATHLON
As soon as you stop training, you’re losing fitness, but taking it easier before your race is essential to recover and feel fresh for your event. Tapering is different for each individual, but it’s about doing less than during your build and should be around 10 days to two weeks long. Try to maintain the frequency of sessions, but lower your TSS by making them shorter and easier – fast brick sessions are good examples of taper workouts.
Racing With a Power Meter
Power is an equally useful measure to refer to during your big race as it is when you are training. “There are two broad benefits to using power in a race,” says Friel.
“In a race, heart rate tends to be ‘artificially’ high early on due to excitement. The athlete who is aware of this is left guessing at what the intensity should be. They usually guess too high and end up positive splitting the course – the first half being much faster than second.
“This doesn’t happen with a power meter. And since it’s measuring output, the user is in sync with what the race is based on – output (time). There is little relationship between one’s heart rate in a race and performance.”
Racing with a power meter is also useful for maintaining mental strength – there’s no second guessing yourself or worrying about overdoing it. You can just concentrate on maintaining a steady cadence, knocking back your nutrition and keeping good technique.
After all the training hours you’ve put in and data you’ve collected from rides and simulations, all you need to do is spin out of transition and stick as closely as possible to your IF range.
After the swim, the start of the bike ride is bound to feel too easy, but ignore the uber bikers who are looking to make a name for themselves and keep to the plan, tackling hills as efficiently as possible to help you sail into T2 and off onto the run, already on your way to a PB.
Pro Triathlete Power Sessions
2nd Ironman World Championships 2013
Training with a Quarq power meter allows me to get more value out of each training session and takes out the guess work. I can set my goals pre-session and monitor my efforts more effectively. With good consistent training you can see improvements in strength and fitness levels.
Much like in training, racing with the Quarq allows me to pace myself, especially in a constantly changing environment with wind, hills and other riders. I know from experience and training where my threshold for Ironman is and it not only allows me to ride to my potential but also sets me up in the best shape to run a marathon.
My favorite power specific session would be where I ride 10/10/10 minutes at 30 watts under IM pace/ at IM watts/ 30 watts over IM watts and repeat the set three or four times.
Winner Ironman 70.3 Auckland; Ironman 70.3 Oceanside 2013
Ironman, as far as I think, is all about consistency. If you could mentally cope with it, riding on a trainer is ideal because it’s so efficient.
A power meter allows me to add a bit of sports science while still doing what I love – going out on the road for a ride.
Racing with power gives me an indication of pace and cadence. Sometimes you do just have to let it all go and get your butt up the hill but in many ways it makes racing much easier.
All my sessions are power specific but my favourite and most hated at the same time is 10x2min at 6W/kg on a TT bike.
Ironman 70.3 World Champion 2012, 2013
I thought that I was pretty good at training by feel, but especially when it comes to intervals I realised I’m not.
It is way better to do your intervals with a Quarq power meter. I often started way too hard and then my power dropped too much.
On easy rides, it is better to set a goal like: don’t go over 200W avg. You could also see progress much better than without a power meter.
I really love to do a power meter session on the home trainer. The main set is:
1min @ 580W 1min @ 200 W
2min @ 480W 1:30min @ 210 W
3min @ 440W 2min @ 220 W
4min @ 400W 2:30min @ 230 W
5min @ 380W 3min @ 240 W
6min @ 360W 3:30min @ 250 W
7min @ 340W 4min @ 260W
8min @ 330W 4:30 @ 280 W
It does not look that hard but you fall off the bike if you are not fit.
Joe Friel is co-founder of Training Peaks and author of The Triathlete’s Training Bible. To find out more about power, we’d recommend Joe Friel’s book The Power Meter Handbook: A User’s Guide for Cyclists and Triathletes.