What should be my target power for a virtual race? We often get this question. More and more runners are getting acquainted with running on power. That’s not complicated. It’s new and therefore sometimes unfamiliar. But very suitable for virtual races. You’re running alone. You can’t focus on anyone and you don’t have a reference. Unless you’re running with a running power meter. Then you only have to keep an eye on one number on your running watch. That’s the wattage you can handle at that distance.
Where did you get that wattage?
You can have a look at our book The Secret of Running and understand all aspects that affect your running performance. You can also use rules of thumb. Hans spontaneously gave an example for this last week.
How did that happen? We were allowed to check out a few options for the cover of our new book. On the cover is a runner who runs a half marathon with 284 Watts and has a goal of 1:41:32 as time. That runner weighs 75 kg, Hans said immediately.
Hans used the simplified formula P = 1.04*m*v
In the formula, P is the wattage (in Watts), m the body weight of the runner (in kg) and v the running speed (in meters per second).
If you run 1:41:32 at the half marathon, this is equivalent to 289 seconds per kilometer (average pace 4:49/km). The running speed is then 1000 meters divided by 289 seconds = 3,46 m/s. So with a wattage of 284, the body weight of the runner must be 284/(1.04*3.46)= 75 kg.
And to get a useful answer to the question how to get the wattage for that virtual race: suppose you want to run at a pace of 5:00/km. 1000 meters divided by 300 seconds yields a running speed of 3.33 m/s. And if you weigh 80 kg,for example, the power you should maintain in that virtual race is: 1.04*80*3.33 = 277 Watts.
You can use that 277 Watt as a target if you’re running with a Stryd, a Coros watch, or with an app like Power2Run for Apple watch. At Coros and Power2Run you have to remember that they do not take into account the wind. The factor 1.04 applies to calm weather with little wind.
That’s also the case when you’re running with Polar Running Power and Garmin Running Power. These also have no wind measurement. Moreover, the definition of power at Garmin and Polar is different. Garmin and Polar users need to increase the power calculated with the simplified formula by 25-30%.
ProRun has a calculator on the website that contains the simplified formula. The calculator is actually intended to determine the power you run during interval training.
To do this, you need to indicate what your body weight is and how many seconds you want to run per 100 meters.
In the example of a pace of 5:00/km, that is 300 seconds per 1000 meters, so 30 seconds per 100 meters. If you enter that in the calculator, you will see that here too the result is 277 Watts for someone of 80 kg.
What pace can I run?
In order to calculate the power in the above way, it is necessary that you know what pace is achievable in calm weather on a flat course. The factor 1.04 in the formula is based on this situation, as mentioned earlier in this article. When the wind blows harder, the air resistance is higher and a higher wattage is required to run your intended pace. Usually your pace will go down as a result of the wind at the target power. In a next article we will show in a handy table what wind does to your wattage and pace.
Unfortunately, in this day and age there are few real matches where you can deduce from what your pace should be. If you do know that from one or more distances, you could use the table below. Per line are the corresponding achievable times for different distances. Of course, you can also use the calculator on the website www.TheSecretofRunning.com
Our book ‘The Secret of Running’ is for sale in our webshop. Also available in German as ‘Das Geheimnis des Laufens’, and in Italian as ‘Manuale completo della corsa’.