A New Metric That Will Change Running Forever

Jon Ackland
Nov 6, 2018 · 4 min read
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A huge part of training for an event — whether it’s your first 10K or a marathon — is having the right metrics to guide your performance. Our running app (currently in beta stage) has the usual important running intensity metrics like speed/pace (min/km or min/mi), heart rate but it also has a relatively new metric: Power, measured in watts. (e.g. 124w)

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Power metric on the Arda coaching app (indicative screen only)

Power on our running app does not require an external sensor as is required with other commercial solutions so there’s no extra cost or trouble pairing.

Once you get used to the numbers and understand the benefits, you’ll find power is a superior and more helpful metric that will positively impact your training.

Some advantages of using Power during your runs are:

Always know what the right effort is:

During your longer runs, you’ll usually try to run evenly throughout the run. You might normally use Speed or Pace as the metric for this. The problem is that hills mess this up! As you run up the hill, your speed slows down making it difficult to clearly know the correct pace to keep things even. Power as a metric takes gradient into account so you can evenly run at say 200 watts no matter what the terrain.

Stay in control of your performance:

The sports world has been very ‘lungs’ (cardiorespiratory) orientated in the last few decades with heart rate measurement dominating. If I asked you what the limiting factor was in say a half marathon, leg fatigue or lungs fatigue, what would you say? Most people say legs. Heart rate doesn’t tell you much about your legs. Heart rate just rises as you get tired. Speed doesn’t help much either. It doesn’t highlight what fatigues your legs.

But power does. As most people run up hills, their power spikes (running on: flat = 200w, hill = 290w). Think of each power spike as a match being struck from a box of matches. There is a point where you’ve burnt so many matches that you run out. That’s when your legs ‘give out’. With power you learn how to control the factor that limits your performance in an event.

Important metrics like Power from ARDA, show up when you sync to Strava**

Get immediate feedback:

Doing speed work with heart rate can be troublesome because there is a lag between when you initiate the higher speed and when your heart rate finally stabilises to correctly define the effort. This can take between 30 seconds and 90 seconds.

Because of the discomfort of speed training, 30 to 90 seconds is a long time in the ‘pain locker’ while you are waiting to see if you have the right effort dialled in. Less experienced runners often overshoot the correct effort, running too hard.

When using running power, you just dial in the correct effort and get immediate feedback. No delay, no uncertainty.

It’s terrain agnostic:

Preparing for an event often involves simulating the correct effort. For example, running 10km in 60 minutes means 6min/km (9min 42s/mi) pace. Using heart rate as your simulation metric is problematic because it fluctuates daily (higher HR some days and lower HR others to achieve the same simulation speed) which doesn’t clearly define the 6min/km (9min 42s/mi) required to simulate your target. Speed and power are much better for simulating race pace and as already discussed, unlike speed, power has the advantage that it can be used on any terrain.

Get even more insights:

Finally, the other advantage to your training is understanding the relationship between your actions and your body’s reaction to exercise. Ideally you initiate an action (running at a power) and your body demonstrates a reaction (heart rate changes).

This tells you how your body is responding to your training. Using power to measure the action and heart rate to measure the reaction, a whole lot of other useful insights open up to tell you how your training is going. But that is a story for another day…. 😊

Power is going to change the game for running. Test it out with our app, and let us know what you think!

Our running app is in beta stage and we’re looking for more testers! If you have an Apple Watch Series 3 or above, get in touch! Otherwise, join our community on Twitter, Telegram or Facebook to stay up to date as we get closer to launch day.

**note — the Strava integration display may change

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