Herriott Sports Performance

There are a number of ways to judge the intensity of a ride, with heart rate, power, and perceived exertion being the most common. Unfortunately, a lot of riders learn to ride and race using wattage as their main metric, and never learn how to tell how they feel by perceived exertion.

Power meters are great. They give riders all kinds of useful data about training and racing, and help their coach design training to prepare the rider for actual race conditions. Power meters are especially useful for measuring work done and setting intensity goals to hit during mid to short duration interval sessions. I thoroughly believe that when used properly, wattage can be a great tool.

A strength of measuring wattage is that a watt is a set intensity all the time, every day. What must be understood is that consistent wattage reading doesn’t necessarily mean that a certain wattage always gives the same training stimulus. Consider this – on a normal day, a rider may be able to ride a steady 250 watts fairly comfortably, burning mostly fat, and this may be considered a mid-Z2 endurance ride. On another day, after a strenuous training session, maintaining 250 watts may be uncomfortable, heart rate is elevated, the rider uses far more carbohydrate to produce the wattage, and the intensity is quite difficult near the end of the ride. It’s clear that the 250 watts is causing a far different training stimulus than on the day prior. Does this mean that the 250 watt ride is still training the basic endurance systems, or is it a higher intensity tempo ride? This is a limiter of using only wattage.

The rider using wattage with heart rate would see that their heart rate is elevated for 250 watts, recognize they are riding at too high of an intensity for an endurance ride, and adjust their effort accordingly to reach the desired training stimulus. They will continue the ride at a lower wattage, but will be at the correct physiological training stimulus – the main goal of the ride in the first place!

We tend to emphasize power meters because they are new and interesting, but it’s important not to forget about the basics of heart rate and perceived exertion. Heart rate being one indicator of physiological function, and perceived exertion is to sum up how the body is feeling at a given moment. If the battery on your PowerTap is out, you should still be able to get out for a quality ride!

Consider top level professionals at the 2009 Time Trial World Championships. Three of the top ten riders had a power meter on their bikes. If there were ever a situation to use a power meter for pacing, it would be in a time trial. If it were truly the most important metric, then it would be on every bike in the field and riders would check the numbers repeatedly throughout the race. These riders are great not because they know their wattage, but because they are excellent at pacing themselves based on perceived exertion.

Remember – power meters are a great tool, but don’t live and die by the numbers. If you haven’t in a while, try a few rides without the power meter and get a feel for your body, the most important part of all.

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