Knowledge is power and power is the driving force for triathletes and cyclists alike.  How we use power in our training and racing will greatly affect our physical ability and the subsequent outcome of our race performances.  The following concepts will help guide your thinking when using the power meter. 

POWERMETERS AND RACING

As a coach I am constantly asked whether or not an athlete should use a power meter to  race an event.  Depending upon the distance my recommendations will vary.  My response has been to train athletes with power but when it comes to raceday trust their instincts and confirm it with heart rate. (Especially so for long course triathlon) 
I am a big proponent of data collection during races and thus I do invite athletes to cover their wattage and rather race with a specific intensity and only confirm that intensity with a heart rate monitor.   Why should this be so?  During longer events such as an Ironman, the long day energy needs must be respected.   A heart rate is a key indicator of this energy balance when considering the lactic threshold and the heart rate at which an athlete can perform most aerobically for a long event.  The lactic threshold wattage and lactic threshold heart rate are not directly correlated and heart rate may vary on any given day and event.)It is the variability between the two that we actually best determine cycling fitness during training and racing. 
Even during training we know generally what power we can hold for a long distance event based on testing.  Yet pacing with power may increase the chances of giving too strong and too early an effort (vs heart rate) or our late stage efforts not strong enough.  Take for example the effect more specifically in a 70.3 event or an Ironman where the heart rate soars out of T1 and onto the bike where an unchecked heart rate can lead to greater energy loss as you try to maintain a specific wattage.  (A constantly jumping and changing target as pressure applied and removed from the pedals can create troughs and spikes in power)  Similarly, once into the ride it may also occur that power again holds an athlete back from their raceday potential.  When you fully taper for an event, you may be capable of more on that day and if you stick to the prescribed power numbers you may miss your true potential for the day!
Another disadvantage to the power meter is that it takes you out of the flow of a race.  The "art” of racing allows you to listen to your body and go for it when you need to and best adjust to the demands of the course.  A heart rate will give you a better global picture of how hard your body is working yet still allow you to put out a good effort without compromising race speed.
This speed may not be realized when using a power meter especially if the course is more dynamic, technical or hilly.   For many athletes rolling hills represent opportunities to ride faster that cant be fully appreciated when plugging in a specific wattage during a race.  Understanding that all "Power is not created equal” on a course will help you to learn where to put your efforts; herein lies the true sophistication of the power meter when used during training versus racing.
So why all the rage with power meters and the touting of their benefits if its not going to help me with my race?

HOW TO TRAIN MORE EFFECTIVELY WITH POWER

-The long ride:  Using power to make sure a steady/easy ride is… well, steady and easy!
 The use of a powermeter during the long ride should really drill into you how to "go easy” and smooth out the profile of the ride. When you ride and keep your watts at an endurance pace you notice hey, my easy ride is easy and this is due to the fact that hills get neutralized and the flatter sections of a course get utilized!  If you keep your workload the same at "X” watts it doesn’t matter if you are on a hilly or flat course you will have a similar effort (Note not speed : )

-How to take a hill:  A difference between racing long and training: 

 As you ride up a hill and note your wattage it is clear that the workload has gone up dramatically in order to carry your weight up the hill. During a race if the hill is fairly long it is best to carry as much momentum from the previous hill or flat into the hill by working the gears, peeling them off as you go up.  As the workload increases sit and pick a steady pace to the top.  However if the hill is rolling go ahead and stand the hill and power over the top of it with a little extra effort.  Note: if you were racing by power the powermeter would not allow you to do this and take advantage of the potential energy and speed stored by your weight carried over and down the backside of the hill. By racing with heart rate you would see that the short time it took to power you over the hill had minimal effect on your heart rate and thus was not as costly to your longer pacing strategy. 

-Gold on the backside of the rainbow: Found on raceday as well as a long training ride: 

 As you crest the top off hill out of breath and ready for some downtime on the backside of the hill, look at your power and you will notice that it was cut in half or more.  Why stop there?  Keep going!  When you reach the top of the hill carry your effort over the top and stand on the pedals putting your weight into the downward section of the hill.  Your weight on the top of the hill represents potential energy that you need to capitalize on.  Any extra "sauce” you put on the front end of the hill will be more costly as the more energy will not equate to greater speeds.  However, gassing the backside of a hill until you are up to speed will hoist you in front of the pack and catch up to any hard workers who wasted their energy on the front end of the hill you cruised up. (This does not suggest dogging the hills but rather approaching them with prudence and strength.)

-Working the dowhills:   No fear and an application for racing and long ride training:

 Now that you are applying power on the backside of the hills you will find your speed picking up.  There reaches a critical point at which the economies of pedaling faster have a diminished return and you are better served to rest and stop pedaling in order to conserve energy.  At a speed of 30+mph on the downhill it would be better to save the energy for other slower parts of the course. 

-Intervals!  Love em or hate em the power meter is your carrot to boost your performance.

One of the best reasons to own a power meter is the fact that with each session you can quantify exactly what you are doing from one session to the next and week after week.   A "watt will always be a watt”, what?  Opposed to your heart rate which may be influenced by many factors, (ie sleep, stress, heat ect) power will always deliver the same reading from one rider to the next and these numbers are measureable and absolute.   During interval training each week you can ratchet up your intensity and see true fitness gains based on the work you are doing in your training program.  One key idea with interval training that is important for those new to power meters is noticing how slight increases in power from one workout to the next (and week to week) does not have to be major!  An increase of 10 watts may be sufficient and increments of 20-50 watt jumps in intervals can be a lot of work. 

-Calibration:  all that stuff about accuracy well…..

If your machine is not calibrated you can forget about most of the sophistication we just talked about above… because your results will be flawed!  Make sure to calibrate and zero your power meter before each ride.  Simple, yes, power-full you bet.
To learn more about training with power for your next triathlon program give TriStar Athlete coaches a call and make your training work for you!

All the best,