It’s really difficult to accurately measure whether your runs were efficient or just sucking down your energy. All kinds of factors play in role in judging just how good that run was for you. Everything from temperature changes, to changes in elevation affects things like heart rate, pace and perceived exertion, which are generally used as things to judge the power of your runs. And each of these variations makes it even more complex to understand with any certainty the power of your run, and moreover cannot be accessed in real-time.

It’s said that most running injuries are not a result of faulty running, but over-training and running without much recovery period. The lack of a solid number to determine the power of their runs has pushed runners to go that extra mile, or put in a harder yard, that they really shouldn’t have. So how does one measure running power, the same way we measure say cycling power. With the advancements in sensor-based quantifying and, in particular, the technology to store and use this data, it has now been made possible.

It’s called Stryd and has been developed by an eponymous Colorado-based startup, and created by Princeton engineers. Stryd started a Kickstarter round for crowdfunding in March and by the time they finished it in April, they had well over their goal. 1,297 backers pledged $253,065 to make the running power meter a reality and the company is looking at a mass market launch of early 2016, after delivering the early backers with their Stryd systems.

A Stryd is a button-less oval-shaped sensor device that can be clipped on to shorts. It’s always-on and can sync with mobile devices, smartwatches and other sports gadgets to accurately give runners a power score.

Stryd shows a power score in real time
Stryd shows a power score in real time

As Brian Meltzer who tested Stryd in its development wrote for, “What can a power meter tell a runner? Just as in cycling—a sport that has used power as a training and racing metric for years—a runner’s total power output can be quantified with a single number.” This would give runners a fairly accurate and real-time indication of their work rate. All runners have to do is see their power score, gauge the situation of the race or run and either slow down or increase their work rate as may be the case. It’s essentially giving the power of reliable, actionable data for runners.

Runners have varying stride lengths, and body shape, leg shape and form, and it’s hard to keep track of these factors. So the bevy of sensors and a powerful processor measure acceleration and deceleration within the compact Stryd unit converts the forces of a runner’s forward motion and vertical motion into a value the company calls running power, or center of mass power. This is actually akin to bouncing power, since a runner is essentially bouncing off the running surface.

Allen Lim, who advised on the development of Stryd, and earlier the Powertap hub-based power meter for cyclists, was quoted as saying by Outside, “If you throw a ball down the road, it’ll bounce along fast and efficiently, like a runner with great form. But if you throw the ball at the ground at a sharper angle—one that produces a higher arc—then you’ll need to throw a lot harder (with more power) to get that ball to travel the same speed as the first ball.” It’s the bounce that Stryd measures.

Testing grounds (Image: Stryd)
Testing grounds (Image: Stryd)

And runners and coaches can’t stop singing praises of the system, which has been tested at national marathons in the US and college athletics competitions.

Stryd has been hard at developing the final hardware for the market-ready device and is working with ODM and OEMs in China. The device is expected to receive certification soon, according to the company, while a Spring 2016 date has been set for market delivery.

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