Training with a power meter: the ins and outs

Cycling is a fairly unique sport due to the ability to be able to get a direct measure of workload. Power meters have been around for a few decades already and are able to measure your power output in real time during training and racing. Immediately after the power meters were first released to the consumer market, they were extremely expensive and heavy, use was limited to certain professional cycling teams and others that could afford them. Recent advances in technology have seen power meters become cheaper and as a result their popularity has increased among cyclists of all levels. In this article, we will provide some insight into how we use power meters with our athletes.

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There are really two ways in which your power meter can be used.

  • Setting the training intensity during interval training. Most cyclists who are introduced to power meters fall under the mistaken impression that the most effective use for their power meter is in setting the intensity. However, this might not always be beneficial (which we will highlight below).
  • Collecting data for analysis after your training. Cyclists love data and if we can measure it, we probably will. However, data is only really valuable if it is correctly interpreted. Power output helps cyclists and their coaches monitor training load and, most importantly, progression. Using the power meter to collect data for later analysis is the more effective strategy.

Using the power meter to set training intensity:


Before the advent of power meters, most elite cyclists used heart rate as a measure of training intensity. Heart rate in a laboratory setting is almost always linearly related to power. i.e. as power output increases, so does heart rate and the rate of increase stays consistent. It was therefore a useful way to set specific training zones based on a laboratory test done at the beginning of the season in a performance laboratory.

 

However, out in the field (on the road or trail) there are many factors that affect the relationship between heart rate and power. These include dehydration, temperature, altitude, fatigue, caffeine intake, stress and body position. Together these factors can change heart rate by up to 25 beats per minute for the same power output.

 

Power meters measure the amount of work done while cycling. Power output, measured in watts, is the product of force and angular velocity. Power is not influenced by environmental conditions, fatigue or any other factors, which makes it a less variable measure of intensity than heart rate or rating of perceived exertion.

 

Does that mean you should only use power to prescribe training intensity?


Although power is a very objective and reliable measure of intensity, doing intervals based on power may not be the most effective strategy. A study conducted by Dr Jeroen Swart at the Sports Science Institute of South Africa examined improvements when training by power or heart rate. They took 21 elite male cyclists and trained them using either power or heart rate prescribed interval sessions. Before and after a 4 week training period, the athletes completed a VO2 max and peak power output test as well as a 40km time trial. To ensure that they had all performed exercise at the same intensity, the average training power outputs and heart rates from all the training session for each group were compared. They were identical. When the performance tests were compared, the peak power output tests showed that the heart rate group had improved by over 5% while the power group had improved by only 3.7%. Analysis determined that the heart rate based intervals were 60% more likely to result in improvement than the power based intervals.

 

If both groups trained at the same average intensity, how can that be? Well, another often cited deficiency of heart rate monitors is the lag between the increase in intensity of the exercise and the increase in heart rate. This can often be as long as 30 seconds. As a result, the heart rate group had performed intervals where the initial power outputs were very high in an attempt to get the heart rate up to the target. Later in each interval, the power outputs dropped off significantly, ending up much lower than that of the power group. The power group, as expected, churned along at an even intensity for each interval. The hypothesis is that this initial surge in the heart rate group could have been responsible for the extra training effect of using heart rate.

 

That said, using power to prescribe training intensity can allow the athlete or coach to progressively increase the target intensity and when this is done appropriately, it can force greater improvements in performance. A power meter can keep you honest during your training and prevent you from soft pedalling during your intervals. If you see your power output starting to drop towards the end of your interval, you are more likely to try and put in a little more effort to keep it at the target wattage.

 

At Science to Sport we use both heart rate and power to prescribe training, depending on the specific session. Setting the right intensity requires analysis of the training data to ensure progression and avoid excessive fatigue.

 

Analysis of your training data:


Power meters turn your bike into your own mobile testing laboratory
The reliability of power output data you record during a training session makes it a great variable to be able to accurately measure and monitor improvements in training status. If you are able to produce more power over the same time interval, then you are responding favourably to your current training load. While speed up your local climb can be a used as a more crude measure of progression, it will be influenced by wind, temperature or trail conditions if you are on a mountain bike. Power meters turn your bike into your own mobile testing laboratory and allows you to perform your very own performance tests every time you repeat a standardised training session.

 

Power meters are great for race analysis too. If you are working with a coach or perform all your analysis yourself, race data may allow you to determine what went wrong during your race. Did you go too hard too early? Did you make too many surges early on in the race that you paid for later? How did you pace yourself during the race?

 

In addition, knowledge of the amount of work done (in kilojoules) during your training can allow you to fine tune your nutrition to ensure that your energy intake is matching your energy expenditure.

 

How do you monitor training load with a power meter?


Once you are recording all your training sessions with a power meter, you are able to plot an accurate Performance Management Chart (PMC). There are a number of different applications that enable you to plot a PMC; such as TrainingPeaks, Golden Cheetah and others. The variables plotted on a PMC include your chronic training load (CTL), acute training load (ATL) and training stress balance (TSB). These are defined in the glossary below.

 

The PMC will give you a snapshot of your fitness (CTL) and how fatigued you are likely to be (TSB). How high a CTL to aim for is dependent on many factors such as your training history, age, work related stress and others. A top professional road rider might aim for a CTL of 100-130 while your mid 40’s exec / weekend warrior will be best off with a lower value such as 65 or 70.

 

How can I ensure that my training load is sufficient?


Analysing individual session data will be able to assist you in establishing if your current training load is sufficient to produce optimal gains. Analysing training data will allow you to assess progression. Are you managing to produce a higher average power output for the same interval session? If not, why not? Are you training too hard and not recovering? Do you need to train harder? That’s where an expert coach will come in. They have years of experience and often first hand knowledge through their own racing experiences to guide your training appropriately.

 

As coaches we use a number of metrics to monitor external training load (the stress applied to the body), but also use other measures of stress to ensure that we don’t miss anything. An example is the Lambert and Lamberts Submaximal Cycling Test (LSCT). This and other tests allow us to measure the internal load (i.e. how you are responding to the load).

 

In the meantime, avoid becoming obsessed with the numbers and remember to enjoy your riding as well.

 

 


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About the author: Science to Sport

Science to Sport bridges the gap between scientific research and sports men and women in the field.

 

Utilising scientific tools and experience gained through research and practical involvement at the highest professional and scientific level, the experts at science to sport are able to provide athletes with scientifically validated methods and products which they can use to their advantage during training and competition.





104 Comments

raptor-22, Jun 14 2016 03:18

power meter sales slowing down?

Iwan Kemp, Jun 14 2016 03:20

power meter sales slowing down?

 

From the opening paragraph:

 

"Recent advances in technology have seen power meters become cheaper and as a result their popularity has increased among cyclists of all levels."

Natural Defender, Jun 14 2016 03:21

An interesting read though.

Pure Savage, Jun 14 2016 03:27

Anybody seen a proper marked improvement going from HR to Power training that is not a pro athlete? It makes indoor training sessions easier to execute, but I am not 100% sold on the bike. 

 

I normally just hang on up the climbs and recover till the next one, repeat. Will a power meter make a difference?

raptor-22, Jun 14 2016 03:37

From the opening paragraph:

 

"Recent advances in technology have seen power meters become cheaper and as a result their popularity has increased among cyclists of all levels."

 

 

yes while sales of cyclng related goods are generally down. Popularity does not equal growth in sales over a rolling period.

http://www.bikebiz.c.../tag/statistics

 

generally the industry is in a down turn

LOOK695, Jun 14 2016 03:57

From the opening paragraph:

"Recent advances in technology have seen power meters become cheaper and as a result their popularity has increased among cyclists of all levels."

Still waaaaay to pricey for my wallet😕

EmptyB, Jun 14 2016 04:09

Anybody seen a proper marked improvement going from HR to Power training that is not a pro athlete? It makes indoor training sessions easier to execute, but I am not 100% sold on the bike.

I normally just hang on up the climbs and recover till the next one, repeat. Will a power meter make a difference?


Agreed, for indoor training they are fantastic and that's where I like to use them...but that's it.

They've been around long enough for me to know it won't make any difference to me on the bike outdoors. In fact, I don't wanna look at all that cr@p while I'm riding...

Escapee.., Jun 14 2016 04:18

Anybody seen a proper marked improvement going from HR to Power training that is not a pro athlete? It makes indoor training sessions easier to execute, but I am not 100% sold on the bike. 

 

I normally just hang on up the climbs and recover till the next one, repeat. Will a power meter make a difference?

 

Most guys I know that ride with it, swear by it.

 

Nothing to do with the fact that they are doing 3-5 hours more per week on the bike  :whistling:

Thomo, Jun 14 2016 04:57

Tough to say anything bad once you've invested so much in the piece of equipment. :)

I do think there's enough evidence though to justify the use of powermeters.
But like any training tool, it's only effective when used properly.
Will it make you win races - no, probably not if you weren't good enough to win to start.

Zatek, Jun 14 2016 05:11

I am doing about 5 hours less a week and race in VA. I ave about 8 hours a week and 4 hours is power based training.

Thomo, Jun 14 2016 05:14

Training tools/aids (when used properly) open the door to quality training vs quantity training.

cadenceblur, Jun 14 2016 05:24

Training tools/aids (when used properly) open the door to quality training vs quantity training.


Indeed that's what it's about. They're also like a mirror showing you exactly where you're at.

V12man, Jun 14 2016 05:36

Indeed that's what it's about. They're also like a mirror showing you exactly where you're at.

I find that I can cut out the "junk miles" - my trianing has become more efficient time wise - better results - less time.

 

Now to focus on not falling off the bike so much.... :)

SciencetoSport, Jun 14 2016 07:20

Anybody seen a proper marked improvement going from HR to Power training that is not a pro athlete? It makes indoor training sessions easier to execute, but I am not 100% sold on the bike. 

 

I normally just hang on up the climbs and recover till the next one, repeat. Will a power meter make a difference?

We know how much you chaps love to #Hammer :)

 

We still use heart rate to prescribe training and are firm believers that you can train very effectively with heart rate, no matter the level of the athlete.

 

Power adds an extra variable that allows us to effectively monitor training load and progression (improvements).

 

In addition, the relationship between heart rate and power output and perception of effort helps us monitor fatigue too.

 

As indicated above, information is only valuable if you know how to interpret it.

 

Would it help if we held a talk to discuss this in more detail? I am sure we could organize this if there was enough interest.

SciencetoSport, Jun 14 2016 07:21

An interesting read though.

 

Thank you for the feedback.

SciencetoSport, Jun 14 2016 07:22

Tough to say anything bad once you've invested so much in the piece of equipment. :)

I do think there's enough evidence though to justify the use of powermeters.
But like any training tool, it's only effective when used properly.
Will it make you win races - no, probably not if you weren't good enough to win to start.

 

We agree with you Thomo. Proper use is the only way the value will be demonstrated.

LOOK695, Jun 14 2016 07:29

We know how much you chaps love to #Hammer :)
We still use heart rate to prescribe training and are firm believers that you can train very effectively with heart rate, no matter the level of the athlete.
Power adds an extra variable that allows us to effectively monitor training load and progression (improvements).
In addition, the relationship between heart rate and power output and perception of effort helps us monitor fatigue too.
As indicated above, information is only valuable if you know how to interpret it.
 
Would it help if we held a talk to discuss this in more detail? I am sure we could organize this if there was enough interest.

Yes, some more info would be great. Even when looking at HR based training, it can be a bit confusing. There are different zones based upon max HR, some use HR reserve, then the zones are also configured different i.e. Is zone 3 between 70 and 80% for example or a different % range?

Pure Savage, Jun 14 2016 08:37

We know how much you chaps love to #Hammer :)

We still use heart rate to prescribe training and are firm believers that you can train very effectively with heart rate, no matter the level of the athlete.

Power adds an extra variable that allows us to effectively monitor training load and progression (improvements).

In addition, the relationship between heart rate and power output and perception of effort helps us monitor fatigue too.

As indicated above, information is only valuable if you know how to interpret it.

 

Would it help if we held a talk to discuss this in more detail? I am sure we could organize this if there was enough interest.

 

Thanks for the response, it makes sense in terms of being more effective with the time available. 

 

I saw there was something on the hub the other day about some workshop later in the year, maybe we should attend that.

 

Appreciate the response

pe3nguin, Jun 14 2016 08:43

Training and racing with a power meter - Coggan and Allen

Great read and fantastic place to start

'Dale, Jun 14 2016 10:25

Training and racing with a power meter - Coggan and Allen

Great read and fantastic place to start


Yip
Really superb
Simply written and complicated concepts translated into straightforward ideas

Gerhardc, Jun 15 2016 07:39

What are the cost for an entry level power meter model.....if there is such a thing!!?? :-)

shaper, Jun 15 2016 08:01

What are the cost for an entry level power meter model.....if there is such a thing!!?? :-)

Enjoy reading http://www.dcrainmak...ws/power-meters

 

You wont get much change out of R10k or more... unless you find something in the classifieds 

Skinnyone, Jun 15 2016 08:41

You wont get much change out of R10k or more... unless you find something in the classifieds 

Agreed, but the only PM I would purchase 2nd hand would be a PowerTap hub as at least if the electronics fail, they can replace the electronics, still not cheap to do but at lest do-able (locally)...also they have a decent upgrade path i.e. a 2005 hub could be updated to a 2016 G3...I also saw recently they had a trade in policy recently where you could get discounts on a new system for trading in your old system....that makes sense to me...

NotSoBigBen, Jun 15 2016 08:58

I find that I can cut out the "junk miles" - my trianing has become more efficient time wise - better results - less time.

 

Now to focus on not falling off the bike so much.... :)

 

What are 'junk miles'? I've been cycling for nearly 3 decades and can't recall any of my rides ever containing junk miles or is that only for Pro's ....

scudd, Jun 15 2016 09:12

What are 'junk miles'? I've been cycling for nearly 3 decades and can't recall any of my rides ever containing junk miles or is that only for Pro's ....

Eliminating hours on the bike that have no substantial influence on your fitness goals.  For the time constrained cyclist you see.  Like, too many recovery rides or LSD rides where a fitness base already exists.