Most running-centric fitness trackers measure the same things: heart rate, calories burned, distance covered and cadence. None cover a metric that has defined training in other realms (especially cycling): power.

Stryd ($199) is a different type of fitness tracker. It clips onto your shoe, similar to RunScribe Pro ($199) or the Garmin Foot Pod ($50), but it’s the first wearable specifically made for runners to measure power.

When we spoke with three-time Ironman World Champion Craig Alexander in October, he called running with power “the big thing, or one of the big things coming in.” Along with heart rate, power is arguably the most important metric for competitive runners. We asked Adam Heaney, Head of Customer Engagement at Stryd, to explain why.

Q:
Why is knowing your power important for runners?
A:
Heart rate is your body’s physiological response to energy expenditure. The more intensity that you bring to your activity, the higher your heart rate. Power is a measure of that intensity. For more than 30 years, cyclists have been able to monitor cycling power (intensity) through strain gauges on the crank and pressure sensors on the pedals. In the past 10 years, training with power has become the standard for competitive cyclists, and records have fallen as a result. Stryd allows you to precisely target training zones in any setting: on road or trail, up- and downhill. It also quantifies training stress so that you can make improvements quickly without overtraining, and it identifies inefficiencies in form, technique, muscle strength and conditioning allowing you to target improvements through drills, plyometrics, and specific run training.

Q:
How is knowing your power while running different from cycling? Or are they the same?
A:
It is the same in many respects. By maintaining a steady effort up and down hills you reduce variability of effort and improve performance. But, with running there is an additional element — efficiency. On a bike, the rider is locked into the frame. When running, there are inefficiencies of movement that can be identified and improved.

Stryd: Specs

Metrics: power, distance, cadence, pace, elevation, time
Battery Life: one month of run time
Weight: 10 grams
Other Features: water resistance
Buy Now: $199

Q:
How does Stryd work? And why is it unique compared to other wearables?
A:
Power can be calculated from torque and pressure, like on a bike. But by looking at the formula from a different perspective, it can be calculated by looking at the velocity and displacement of mass. Stryd uses this method to calculate power. By placing it on the foot we can also use the device’s 3D motion-capture capabilities to gather even deeper insights. The original Stryd Pioneer was a chest-mounted device — it measured power and all of the other basic kinematic metrics that are provided by other wearables (cadence, ground contact time, vertical oscillation, HR). These metrics are best understood as the “symptoms” of efficiency, rather than as the cause. Many other wearables try to improve run form and efficiency by encouraging changes to these metrics. Stryd provides a deeper understanding into training load, biomechanics and efficiency. By prescribing specific run workouts, drills, plyometrics, and strengthening routines, Stryd addresses the root cause and enables more efficient and faster running.

Q:
Why don’t most other wearables measure power?
A:
I can’t speak for the reasoning of other companies, but power is extremely difficult to calculate. It requires a vast array of expensive sensors to produce highly complex data. If you want to stream it to a watch (which we do), the data needs to be interpreted within the device itself which requires a high level of processing power. For this reason, power cannot simply be an add-on to an existing wearable; the device has to be specifically designed with the intent of calculating power.

Q:
Who is Stryd for?
A:
At the outset, triathletes have been our biggest user demographic. They have been using power on their bikes to great success, and want to use it to see similar gains on their run. Anybody who wants to run faster will find benefits from Stryd. Users can better target their training and, when using Stryd for race-day pacing, can identify exactly how hard they should run on any course to reach their personal best.

Q:
Does Stryd work with any other wearables, like the Oakley Radar Pace, so that runners can get immediate feedback?
A:
Yes! Stryd broadcasts run dynamic metrics over Bluetooth and ANT+. Any device that reads a bike power meter can display power. Additionally, Stryd has been found to be the most accurate distance-measuring device on the market, and distance and pace can be displayed. This is particularly appealing to urban runners (or trail runners in canyons or dense forests) that may have unreliable GPS signal.

Q:
How can the next generation of Stryd improve? What else are you working on?
A:
Most of our improvements from this point forward will likely come on the software front. We would like to provide a smoother and cleaner overall user experience. There are several advanced metrics that we are looking into that should make the learning from Stryd more actionable. Finally, we want to beef up the coaching side to better integrate supplemental work — drills, plyometrics, weights, etc.

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