Running Power: Useful or Just a Gimmick?
Your watch may show watts on every run, and you wonder if that number is useful. Four running situations show when power helps and when pace is enough.
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The short answer
Running power is mostly useful on hills and for repeating the same effort from one workout to the next. It is estimated with formulas, not measured the way it is on a bike. In a 2021 study of five technologies, Stryd was the most repeatable (variation of 4.3% at most), but the authors of a trail study advise caution about using Stryd and Garmin interchangeably. Stick to one device.
Key takeaways
- In running, power is estimated with formulas, not measured directly as on a bike, and the authors advise caution about using two devices interchangeably.
- Power is most useful on hills and for repeating the same intensity from one workout to the next. On a steady flat route, pace and heart rate do almost the same job.
- A power target for a half marathon is a starting point with a margin of error, not a number to follow to the letter.
- Stick to one device and compare yourself to yourself.
Your watch may already show watts on every run. A round number, a nice graph, and one question: does it actually help?
Here is a test in four situations you really run into: a hill, a steady pace on the flat, a long run, and a race. For each one, there is a single question: does power tell you something that pace or heart rate doesn't already?
What watts actually measure
On a bike, the sensor measures the force on the pedals directly. In running, a foot pod or a watch estimates power from formulas and motion sensors (accelerometer, GPS, barometer, gyroscope), as a 2026 review of the Stryd sensor describes.
This estimate is not exact in absolute terms. On a treadmill at 6% and 8% incline, Stryd slightly underestimates metabolic power (the energy your body burns), by roughly 2 to 4%. So watts are a relative marker: compare yourself to yourself, with the same device.
Test 1: the hill, where pace lies
You run at 5:30/km (8:51/mi) on the flat. On a hill, you drop to 7:00/km (11:16/mi). Your pace says you eased off, but your body is working just as hard, if not harder.
This is where power makes its strongest case. In the treadmill study, running at a fixed Stryd power gave a fairly steady indication of metabolic demand from one incline to the next.
Verdict: yes, power adds something on hills. The limit: the study was done on a treadmill, with slopes up to 8%. It says nothing about technical descents or trail running.
Tests 2 and 3: steady pace on the flat, then the long run
On a flat, steady route with no wind or terrain changes, pace and heart rate already do the job. On that kind of day, power has only one edge: repeatability.
A 2021 study compared five technologies on a treadmill and on a track, with 12 men trained in endurance. Stryd was the most repeatable, with a variation of 4.3% at most between two measurements of the same effort. Garmin, Polar and RunScribe were judged not very repeatable under these conditions.
On a track, another study (15 highly trained athletes) shows that power models 60-minute performance better than GPS speed.
For the long run, a target power lets you compare two runs at the same intensity. To find out whether your fueling worked, your heart rate and pace over the last third are what tell the story: Long run fueling: how to tell if it worked.
Test 4: the race, between a useful target and false precision
"What power should I race my half marathon at?" There are two markers, and each has its margin of error.
The first is the critical power that Stryd calculates from your usual training. In 20 runners tracked for at least 6 weeks, it was close to the second ventilatory threshold (the point where breathing starts to spiral). The individual gap with that threshold ranged from 20 to 40 W, or 7 to 13%, with roughly 5% variation from one day to the next.
The second is a formula built on trained athletes, using a 9- and 3-minute test: half marathon power = 0.97 + 0.75 × critical power, in W/kg. With 4.0 W/kg, this gives 3.97 W/kg. The standard error is 0.29 W/kg, so your realistic target falls between about 3.7 and 4.3 W/kg.
Verdict: a starting target, not a number to follow to the letter. If you are preparing your first half marathon, first half marathon training is still your base.
Watch or sensor: watts don't compare across devices
Since power is estimated, the authors of a trail study advise caution about using Stryd and Garmin interchangeably, because of inconsistencies they observed. In the 2021 study, Stryd was the most repeatable while Garmin and Polar were not, but only on a treadmill and a track.
Studies give you validity, reliability and performance modeling. Coaches add the practical side: holding a steady effort on a hill, repeating a key workout at the same intensity. No trial shows that a runner improves faster with power than with pace or heart rate.
The rule: one device, and only compare yourself to yourself.
What you can do on your next workout
| Situation | Does power add anything? | Why |
|---|---|---|
| Hill | Yes | At the same watts, effort stays close from one slope to the next (treadmill, up to 8%) |
| Flat at steady pace | Not much | Pace and heart rate are enough |
| Long run | A little | A comparable marker from one week to the next |
| Race | Depends | Starting target, with a 0.29 W/kg margin for a half marathon |
To test it without getting lost:
- Pick a key workout (hill repeats, or a block at a strong pace) and note your average power and pace.
- Repeat the same workout two weeks later and compare watts, pace and heart rate.
- Don't aim for an exact number. Give yourself a margin, for example around 5%, the day-to-day variation observed on critical power.
Keep your heart rate zones in view, since they remain a safety net:
Free calculatorHeart rate zonesOpen the calculator →KILYO reads your workouts from your watch and tracks pace, heart rate, volume and consistency. That is what it uses to adjust your plan, whether your watch shows watts or not.
Power is useful if you often run hills or like repeating a workout at the same intensity. It stays a gimmick if you mostly run flat at a steady pace.
Frequently asked questions
Is running power more reliable than pace or heart rate?
Should I buy a Stryd sensor, or is my watch's power enough?
Why don't my watts match between my watch and my foot pod?
How do I find my critical power or threshold power?
Should a beginner train with power?
Sources
- Use of the STRYD Power Meter and Its Metrics in Trained Runners: A Systematic Review (2026). Sports, 14(8), 364. DOI
- Cerezuela-Espejo V., Hernández-Belmonte A., Courel-Ibáñez J., Conesa-Ros E., Mora-Rodríguez R., Pallarés J. G. (2021). Are we ready to measure running power? Repeatability and concurrent validity of five commercial technologies. European Journal of Sport Science, 21, 341-350. DOI
- van Rassel C. R., Gow M., Watanabe K., Jaén-Carrillo D., MacInnis M. J. (2026). Validity of Stryd Running Power for Estimating Metabolic Demand During Incline Treadmill Running. International Journal of Sports Physiology and Performance, 21(4), 597-603. DOI
- Ruiz-Alias S. A., Ñancupil-Andrade A. A., Pérez-Castilla A., García-Pinillos F. (2024). Power or speed: Which metric is more accurate for modelling endurance running performance on track? European Journal of Sport Science, 24(11), 1597-1603. DOI
- Dearing C. G., Paton C. D. (2023). Is Stryd critical power a meaningful parameter for runners? Biology of Sport, 40(3), 657-664. DOI
- Olaya-Cuartero J., Pueo B., Villalón-Gasch L., Jiménez-Olmedo J. M. (2023). Prediction of Half-Marathon Power Target using the 9/3-Minute Running Critical Power Test. Journal of Sports Science and Medicine, 22, 526-530. DOI
Written with the help of AI.
