SHOULD YOU BE DOING POWER METER TRAINING?

Here’s answers to why road cyclists should use a power meter, how to train with one, when it’s right to get in and whether you need the latest features.

I recently finished with my latest update of the Best Power Meters For Road Cycling Enthusiasts review.  It sorts through all the new power meters introduced over the last couple of years and adds my fresh analysis of what’s important for cycling enthusiasts (vs. elite athletes), the four essential requirements for power meters, and which I rate as the best performer and best value.  As in my past power meter reviews, I’ve considered price, transferability, compatibility, availability, and market and product developments to come up with my recommendations useful for most enthusiast-level road cyclists.

This should take you from trying to sort through all the information out there on your own and being left with the recommendation that “it depends” to you being able to say “I’m confident I know why this is the best power meter for me” and “I don’t need a salesperson to tell me what to buy.”

But, let’s take a step back and answer a basic question – why should you use a power meter in the first place.  I’ll answer that question in this post and tell you how I train with one and try to help you decide when you should start doing so.  I’ll also give you my perspective on the issue that seems to hang most people up when trying to decide between power meters these days – whether to spend the extra money to get a power meter that does independent leg power measurement and gives you pedaling metrics – and a look forward to see if any developments I can foresee will change things in a big way.  

WHY TRAIN WITH A POWER METER

The format of this blog allows me the space to explore whether using a power meter is the right thing for you and how you would use one.  I don’t have to jump right in with my reviews assuming you’ve already figured that out.  I also want to be clear that this post and all that you’ll read on this site is geared to road cycling enthusiasts – the regular, serious road riders among us including some who race or ride organized events – and not the top-level amateur racers or triathletes or track cyclists who want and are willing to spend on gear that measures every breath you take (with apologies to the band The Police).

Let me start to answer the question of why train with a power meter by using a few reference points.  First, most of the people in my road cycling club who ride at the A-level (average speed above 21mph/32kph to 25mph/40kph) and B-level (average 18mph/29kph to 20mph/32kph) don’t ride with a PM (or power meter).  Second, even most of those entered in the Kona Ironman world triathlon championships through 2015 didn’t use a PM, as the chart below shows.

Kona Bikes Using Power Meters

So why all the fuss about power meters?

Well, it’s basically that 1) there is no better training tool or piece of gear or kit you can buy to efficiently improve your fitness and performance, and 2) power meter prices have come down to where they won’t send you (or your bank account or your better half) into shock if you decide to buy one.

Let’s look at each of these reasons.

Training to improve your power and efficiency (power achieved at a given heart rate) at higher stress and intensity levels will make you fitter and faster.  You can’t just go out and try to go faster on each ride.  That’s not training.  If you were a runner and wanted to sprint faster, would you just go out and sprint every day trying to go a little faster than the day before?  Of course not.  It’s the same with cycling.

A PM measures the output of your engine – your muscles – more effectively than a heart rate monitor, watch, or your own assessment of ‘perceived effort.’  These are the tools cyclists relied upon before PMs.  A heart rate monitor only measures the output of your heart, which pumps blood to your muscles but doesn’t measure how hard your muscles are working with that blood.  A watch or speedometer measures the result rather than the work of your muscles to get that result.  And while ‘perceived effort’ is a pretty good physiological system, it subjectively gives you feedback on how hard you worked rather than objectively telling you how hard you are working.

Being able to quantitatively know how much power your muscles are putting out in real-time allows you to tell your engine how hard to work during intervals, hill repeats, sprints, pacing, below threshold base building or whatever your training calls for.  It will also help identify your strengths and weaknesses and manage the amount of work you do on hard days and on recovery days so you don’t over-train. This is the way to get the most out of your training and riding time, to be the most efficient and effective you can be in raising your level.

The costs of acquiring and using a PM have come down rapidly.  Before Stages Cycling came along with their line of PMs just 3 years ago, most people who bought direct-force PMs usually spent anywhere from $1500 to $2500 or the £, €, AU$ and other currency equivalents on a unit.

But that wasn’t all it cost you to train with a PM.  Because PM use was still rather limited, there were different views on what the data produced by PMs meant and what to do with it.  That usually meant you had to hire a coach at a couple hundred $, £, €, etc. per month to interpret and apply the data for you if you wanted to put the PM and a training program to good use.

Hunter Allen, Andrew Coggan, and Joe Friel, and the software tools and analysis site Training Peaks they and others helped build have led the way in creating well established power metrics and commonly accepted views of what cyclists should do with those metrics to improve cyclist training and results.  Their efforts brought power-based training from more art than science to more science than art.  At the same time, companies who make PMs and the cycling computers or ‘head-units’ that read the PM data coalesced around these approaches and metrics in their products and also around the ANT+ protocol that communicated between them.  Coaches and power meter training plans also followed.

Today, you can buy several direct force power meters in the $500-$1000 range.  You can also buy bike computers (or ‘head units’) for $150-$300 that convert the power meter data into those metrics.  And, you can go a long way with pre-built, 3-month power meter training plans for about $100 each that use PM data and metrics to guide your training toward specific fitness or performance goals.

In summary, we’re now at the point that judging your performance by your ride speed, time and distance and training using a heart rate monitor or measuring your perceived effort are not only outdated and ineffective compared to power meter training, but you can now afford the cost and more easily understand and use the output of a PM to greatly improve your training and ultimately your performance.

HOW YOU USE A POWER METER TO TRAIN

For those who want to back up before diving in, no worries.  Let me try to make it simple by explaining how you can train with power.

Fundamentally, you use a PM to train knowing the threshold level of power you are able to produce on your bike.  Above this level lactate begins to accumulate in your blood and your muscles begin to fatigue.   Your body’s energy demands can no longer be fully replenished by the fuel it can supply.  Too far below this level, you aren’t working your muscles enough to improve your performance.  By training with a mix of below, at, and above threshold-level workouts, along with proper recovery rides and rest periods, you can improve your fitness and performance over the course of your season.

To determine your threshold power or what’s called your FTP (functional threshold power, measured in watts), you warm up and then do an all-out twenty-minute ride on a flat to slightly pitched route or on an indoor trainer before the beginning of a new training cycle.  You then design or use a plan to meet your cycling goals by doing power meter training in zones determined by your FTP.

Your plan looks out several months to a year and then backs into monthly, weekly and daily workouts designed around your goals.  You guide each daily workout by your real-time power output, rather than your speed or heart rate, in concert with other measures like cadence and interval distance.

Let me illustrate with a snapshot of how I train.  One of my goals is to do one fast century length (100 mile) ride, often with lots of climbing, every month from May through October.  I’ve got a bunch of rides I and some of my riding friends like to do and each one is a different ‘adventure’ but requires a similar level of strength, endurance and speed around which I can train.

Screenshot 2015-04-14 11.51.18

A few weeks from an early season (and not very well executed!) training plan

To get fit for these rides, my training plan includes doing hill repeats (or multiple trips up hills) of various pitch and length.  This, along with an early season weight lifting plan, builds and maintains strength through the season.

To improve speed, my plan also calls for me to do flat intervals or high intensity efforts of various lengths.  Finally, the plan requires that I do some long distance rides to build my endurance.  And, thankfully, the plan also requires that I recover by riding easier days between the harder ones and gives me an easy week every 4th week.  I usually try to ride the century or do another FTP at the end of that 4th week.

Say my FTP is 200 watts when I test it at the beginning of the season.  Knowing my FTP allows me to define 7 training zones, each with a different level of output.   (I actually just pump FTP into my head unit and it calculates the zones for me

For example, Zone 2 is the Endurance zone where you ride at 56-75% of your FTP.  If my power meter training plan calls for a 2 1/2 hour endurance ride, I’ll ride it in that zone, glancing down at my head unit from time to time to make sure I’m somewhere between 110 and 150 watts (or 56-75% of my 200 watt FTP) throughout the ride.  I’ve set up my head units so I can see both my actual 3 second average power output and what zone that puts me in so I don’t have to calculate it while I’m out riding.  (Good thing!)

Depending on the length and intensity of what the training plan calls for on my hill repeats and intervals, I’ll ride them in Zone 5 or the VO2max zone (106-120% above my FTP), Zone 6 or Anaerobic Capacity zone (121-150% of FTP), or Zone 7 or Neuromuscular Power Zone (>150% of FTP).

On my easy or recovery days after harder rides, I’m in Zone 1, the Active Recovery zone (<55% of FTP).  When I’m doing base training or riding with a group, I’ll usually train in the Tempo zone (Zone 3, 76-90%) or in the low Lactate Threshold or Zone 4 area (91-105% of FTP).  All of the zones will be specified in my power meter training plan.  Once I know my FTP and feed that into my head unit, I just need to ride the zone or zones called out in each day’s plan.

As I’ve become more knowledgeable about doing power meter training, I’ve also learned some short hand.  For example, training in the high 3/low 4 zones will burn body fat more than riding in any other zone, good if I’m a few pounds heavier than I want to be ahead of an especially steep climbing event.  I also know how long I can ride at Zone 7 if I want to accelerate going up a hill and know how many watts I can maintain going up that hill after I realized I’ve gone too long in Zone 7.

My Garmin and Wahoo head units both upload my power data to Training Peaks and Strava.  I can review my files at these sites to see how I did against the quantitative goals of each ride and how things are trending over time.

Every eight weeks or so, during a week that I’m scheduled to ride easily, I’ll do a FTP test again and adjust my zones in my head unit accordingly.  Many recommend doing the FTP test every 6 weeks.  My Garmin Edge 520 (available at Competitive Cyclist, Amazon, ProBikeKit code ITK10, Wiggle) can also look at my rides and tell me the FTP of my best 20 minute segment, though I usually don’t go all out without coasting or going downhill for a bit during a 20 minute stretch unless I’m trying to do a FTP.

Depending on how my FTP is trending and what a review of my training files are showing, I adjust my training plan.  If I had a coach (and I’d love that), his or her experience would come into play and I’d get an updated customized plan for the next block of training and perhaps tweak it from week to week within an existing block.

If all I did was look at my speedo or heart rate, I’d really have no idea of whether I’m on target to my training goals on a given ride and over time.  Obviously you can be putting out near the same amount of effort going up a hill or on a sprint but the former might be at half the speed of the latter.  If I just compare my average speed from ride to ride, it’s like the runner who wants to sprint faster by trying to sprint faster each day.  Not ideal to say the least.

I’ve also noticed that my heart rate goes higher as I move through an interval or workout.  On hill repeats or flat intervals, for example, it’s always beating harder near the end of an interval than at the beginning even though I try to keep my effort within a narrow wattage range.  On a long ride, heart rates also tend to drift up over time even with a steady power effort.  Bottom line, heart rate is a lagging and not so go indicator.

Personally, my speed is on my second screen and heart rate on the third.  I only tend to look at them during a ride when I’m curious, for example when it seems I’m riding really fast (or I feel dog tired) despite only being in Zone 2. They give me interesting information but not the kind I can use to train with during a ride.

Of course, there’s a lot more about training with power than my simple example above.  Instead of my average power, I’ll want to know my normalized power at the end of a ride, a truer picture of my power output that takes into account the drop in power when I coast or draft or go downhill.  There are also metrics to tell me how intense my ride was and how much stress my system is taking on based both on my power and physiological efforts.

If you want a more detailed read on the established power metrics and how to use them, check out this article from Joe Lindsey.  For a comprehensive read on all things power, a reference book you should have to build your ability to train with power and use it to your advantage, pick up Allen and Coggan’s Training and Racing with a Power Meter.   It is the authoritative book on the topic.

NOW IS THE RIGHT TIME TO GET IN

For most of us, being better able to afford and more easily use a PM to greatly and more efficiently improve our training, fitness, and performance these days is the good news.  The not so bad news is that power meter training is still a rapidly growing field and, like smart phones a few years ago that were getting bigger screens and improving their computing ability, it still seems like there is always a cheaper PM or a new feature to measure your power output on the horizon.

Take the debate about whether you should have a PM that independently measures the power output of your left and right legs.  This is a rather new development pushed, I believe, by suppliers who have come up with technology to do this and by techies and reviewers who want the latest gadgets to play with and write about.

Most PMs historically measured your total power output.  Some assigned that total power between to your left and right legs based on sensor placement and theoretical equations.  The less expensive units today measure the power coming from your left leg and double it, based on extensive testing that shows that’s a statistically valid approach that produces results consistent with the level of accuracy and repeatability of PMs that measure your total power.

Frankly, repeatability is just as important if not more important than accuracy for the road cycling enthusiast.  To be useful, you really want to know that you are getting a reliable read (repeatability) on how your power output is changing over time.  Knowing that your PM reads 3 or 5 watts lower or higher (but still within the 1.5 to 2% accuracy range most PMs specify) than the PM your buddy has or you are thinking of getting in a couple of years is kind of meaningless for a roadie unless you let it get into your head.

Some will argue based on their testing that relative PM to PM readings are less about the technology each PM uses and more determined by where the PM sits on your bike (pedal, spindle, crank, chainring spider, bottom bracket axle, rear hub) and therefore how far it is away from where the force is being applied.  I’ve never seen a test of this but it makes sense that the further you are away from the application of the force, the more some of that force will get lost in the inefficiencies of your drivetrain.

And honestly, the biggest cause of inaccurate and nonrepeatable power readings come when we forget to calibrate our power meters.  For most PMs it’s simple and quick to do yet we don’t always do it before we start our rides.  So before you write your comments below telling me this PM is more accurate than that one, look in the mirror and tell me you calibrate yours regularly.

From what I’m able to determine at this point, independently measuring the power output of your left and right legs is the equivalent of a cure for which there is no known disease – no one really knows what to do with or even if the independent left/right leg power data can be used to improve your training.  Even the so-called experts don’t know whether your power should be balanced between legs (for most people it isn’t), how much imbalance is acceptable or how you should train differently if you are imbalanced or have certain ‘pedal smoothness’ or ‘pedal asymmetry’ levels derived from independent L/R measuring PMs.

Hunter Allen and his colleagues have come up with tests to measure L/R power and ideas on what you can do with it.  In an article he wrote for the August 2015 issue for ROAD Magazine, he describes the metrics and protocol they have come up with to determine “leg-strength imbalance [that] can help riders fine-tune power output” and “identify a problem with the way you ride your bike (your actual position and form).”

In the Wattage Google forum (free membership required), Allen also writes: “We are still learning lots and more to come.”  Undoubtedly this is advanced, bleeding edge stuff for the most serious riders and competitors out there.  At this point, I don’t think most road cycling enthusiasts will gain a lot if anything in pursuit of their goals with the help of these emerging testing and training techniques.

Perhaps there will be a clear training value established through L/R PMs for enthusiast-level cyclists in the future.  I’m open to that happening.  Top level triathletes clearly are buying these units in the expectation they will get some value from them.  If you look deeper into the types of PMs used at the triathlon world championships the last few years, the independent L/R leg measuring PMs may be the fastest growing category.  The second fastest growing category, however, and one that may be growing nearly as fast or even faster is made up of those triathletes riding in the world championships using PMs that measure left leg power and double it.

Kona L-R PM

Kona Left Leg PM

This data is from the top 2000 or so triathletes in the world, a different group of cyclists than me and probably you, and a group that I would think would be more technically advanced in their gear and more open to trying new training techniques than we more humble roadies.

Also note that the independent L/R and L measuring PMs are both relatively new to the field.  Almost all of the L/R meters in this count come from the Garmin Vector or Vector 2, a PM that has already been surpassed in my view and others by the new PowerTap P1’s superior performance and easier installation and transferability.

There’s an important caveat to the L/R count that I’ve noted in top the chart above and by using the words “may be” a couple times in the paragraph where I introduce both charts.  It’s a caveat that gives the L/R numbers the complete benefit of the doubt and may overstate their position in the PM hierarchy.

LAVA Magazine, the publication responsible for counting all the PMs in this event each year, only identifies the PM brand and not the model, that later which would be near impossible to do in the time they have to make the count.  However, Garmin began selling a L measuring PM called the Vector S in 2014 for a little more than half the price of their L/R PMs.  Some of the Garmins that LAVA counted in 2014 and 2015 may have indeed been these L measuring units.

For this analysis, I had to put a stake in the ground somewhere so I assumed all of the Garmin PMs counted were L/R units.  I had no good reason to do so other than to see how far the attraction to independent L/R measuring PMs might have gone with this elite group of athletes.  If however, the Garmin L measuring units made up a quarter or a half of all the Garmin PMs in the count, obviously the share and growth picture would look quite different.

All of the L measuring PMs in the lower chart above are Stages Cycling PMs.  Stages has established a price target, plenty-good performance level, and left crank form factor that many of the incumbents and new PM competitors are copying or trying to improve on.

In my humble opinion, it’s more likely that L/R leg measurement will become an extra feature that some want, much like handwriting capabilities on the so-called Samsung phablets or phone-tablet hybrids.  The current PMs and power training methods are far along the design and use curves and the like that we have seen in other industries including mobile phones.  Each new PM at this point is likely to push down the price or add a feature or two to differentiate them rather than change the fundamentals of PM operation and performance or how to train with them.

Fortunately, this L/R debate appears to be the only one of any significance on the horizon for the next several years.  I base this on a review of the power measurement approaches of the nearly dozen new PMs that have been announced but not yet refined to the level of commercial introduction.

We’ll see, but I think if you get in now, there’s very little risk that the PM you buy from among the ones I’ve evaluated in this review will become obsolete in the next 3-4 years or be missing must-have features that you can’t get through a firmware update.  Prices will continue to come down but after the drops we’ve seen lately, I think you are at the point of trading off whether you want to save 10% to 20% by holding out another year or improve your fitness and performance by a similar amount by getting started now.

WILL THE ELEPHANT IN THE ROOM PLEASE ANNOUNCE HIS INTENTIONS

Of course, there is an elephant in the room that finally began to squeak, but only like a mouse. Here’s what I mean by that.

A trend we are seeing in the cycling industry overall is the move to integration.  Bikes with handlebars are integrated into the stems or brakes that are integrated into the design of the front fork tubes and rear triangle are examples.  This trend, while not welcome by some due to a lack of flexibility or choice in components, seems to give opportunities for bike makers with large market shares like Specialized, Trek and Giant to further consolidate their influence and control.

Along these lines, I wouldn’t be at all surprised if Shimano (the elephant I was referring to above) integrated a PM into their groupset in their pedals, crank arms or chainset starting with an 2017 or 2018 introduction of their next road groupset update.  They have demonstrated their electronics capabilities with their highly successful Di2 groupsets and they have the overwhelming, dominant share of groupset business on new and enthusiast-level road bikes.

For 2017 model Dura Ace 9100 cranksets, Shimano is selling their first integrated power meter. Pricing for the unit and plans beyond this model haven’t been revealed as of the beginning of 2017.

If Shimano stays true to form and strategy, it would be another 1-2 years later before the technology would ‘trickle-down’ to the Ultegra and 105 component levels.  So we are talking about a few years before you could get an integrated Shimano PM/groupset that would be in the price ball park of the $500 PMs that set the price standard today.  Note that $500 is the same amount of price premium you pay between the mechanical and electronic groupsets or the hydraulic and rim brake components Shimano sells today.

Of course if Shimano wanted to put a PM in their SPD pedals, this could happen much sooner and be available more broadly.  However, I don’t believe the PM market is large enough in volume at this time or influential enough in cyclists’ decisions to buy other component products that Shimano sells to motivate them or justify the investment to develop and market an SPD pedal independently of their groupset.  Remember they currently introduce and market both groupsets and wheelsets together.  For example, the Dura Ace 9000 and 9070 groupsets and Dura Ace C50, C35 and C24 wheels were introduced and are marketed together.  Same is happening with the latest Dura Ace line.

SRAM, which already has PM meter know-how through their Quarq brand, could also do this if they decided to cannibalize that line, one that is already bleeding share to lower priced components. SRAM currently is focusing on catching up on electronic groupsets which they will make available in volume in 2016 and integrating that technology into their hydraulic disc brake components.

SRAM is both significantly smaller than Shimano and several years behind them in the market accepting their electronic shifting and hydraulic braking products.  They are also rolling out successors to the Zipp Firecrest wheels line and have a big business in the mountain bike world.

I would think that the relative importance of the road electronic and disc brake markets versus the PM one would make it less likely they would spread their engineering and marketing resources to come up with a more integrated PM solution than what they offer now with their Quarq PM and SRAM groupset combinations.

In summary, I believe it is a very good time to invest in a PM, head unit and power-based training approaches to greatly improve your fitness and performance levels. The PMs and training methods available now are both cost-effective and user-friendly enough for most any road cycling enthusiast to get great value and benefit from.

What we know is coming down the road over the next several years and the elephant-in-the room type possibilities I can only hypothesize about aren’t likely to change the nature of the power meters you can get now and the training you can do with them well beyond the advances we have seen over the last several years.  Prices will go down further, new features will be added, new players will join in but these will likely be incremental changes rather than the more fundamental ones we’ve seen of late.

If you aren’t yet sure power-based training is right for you or have further questions or comments about what you’ve just read, feel free to enter your thoughts in the comment section below and I’ll get back to you, hopefully with better answers.

Thanks for reading and supporting In The Know Cycling.

5 comments

  • Thanks Steve,
    will be looking forward for another gret gear review

  • Man! Steve! thank you so much! all hats down. I learned a lot from this post and I was in between ideas but I guess now I made up my mind. Article is so simple for novice like me and so informative that I really enjoy reading. For sure I will visit the other two articles about your review. I am in the market for PM as I want to level up my riding quality and my efforts.

    Thanks a lot!

  • Great into to training with power Steve. Waiting now for my new Quarq Red PM to arrive and using power to train for the coming season. Learning FTP then setting zones to train by are my first steps as you describe. Would be interesting and informative reading some items you’ve learned in your time using power. Thanks for the well written and logically presented information. Well done!

  • Best bang for buck – buy a direct force PM, train 3 x 1hr at 85%-90% of FTP.

    • Simon, All due respects, if you never train above your FTP, you’ll never raise it. Shorter, high intensity train and a variety of power training will also help you improve your performance than doing the same training program each time. Steve

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