Running Power. Why you need to get on board with the future of running

Updated: Mar 12, 2021

Spending $200usd on a piece of kit that isn’t shoes and isn’t a watch is an outrageous proposition to any runner. In fact, I recall being ridiculed for buying a GPS watch (Garmin 405) in 2010! Over the last decade, runners have accepted GPS devices and understood their true value - uploading to Strava and proving every race they do is a few hundred meters/yards long.

Joking aside, GPS and subsequently heart rate monitors have found their way onto the wrists of almost all runners and most, if not all, coaches have an understanding of how to effectively use both pace and heart rate to create faster runners. However, there are shortfalls associated with both pace and heart rate, and that is why power has been introduced to the running the marketplace.


Running power, WTF is it?


Power is the rate of doing work. Work (kilojoules) = the amount of energy needed to run. The faster you run the more work you need to do and the more energy you utilize.


Currently, most runners are monitoring their efforts by measuring how fast they’re moving (pace, min/km or min/mi) and/or how fast their heart is beating; heart rate (bpm).


By measuring the amount of work you are doing at any given time, you can get a more accurate measurement of your effort.


Issues with the Status Quo


GPS - A Measurement From Space


Gravity and Accuracy.


Gravity

How fast should you run up a hill? The answer depends on a multitude of factors; gradient, distance, terrain, position within the race, your weight, the list goes on. In short, we’re throwing blind darts when it comes to gauging our effort on uphills. Yes, you can substitute pace with heart rate, but as you’ll see below, heart rate has its issues too.


Accuracy

If you’re running on trails or in a city with tall buildings chances are your GPS will not be accurate. The fastest sampling rate, how often a GPS coordinate is taken, on most watches is 1 sec, and that’s with a clear line of sight. Switchbacks, right-angle turns, and U-turns can add to the inaccuracy of GPS. If you’ve run 1km in 4min, but your watch has measured 950m your pace will read 4:13min/km. A change of such magnitude (5%) can drastically affect your pacing strategy.


Heart Rate - The Dial-up Broadband of Metrics


When measuring your heart rate, there is a delay between the work you do and your cardiovascular response. It’s referred to as the oxygen (O2) slow component. (more in our Masterclass). At the start of an effort or race, your HR will be low to reflect the low amount of work you’re doing, i.e. standing on the start line. Once you start your race, it will take a few minutes for your HR to respond (during this time there is a higher reliance on anaerobic energy production). It usually takes around 3-5 minutes to reach a steady-state in both HR and oxygen consumption. At this time, HR is not reflective of the work being done, and it’s not possible to accurately measure the effort.