Running with Power

For the last six months I have been trying out a new gadget for running. It's called Stryd and it's a power meter for runners. Cyclists have been using power meters for decades to optimize their training and racing so I was intrigued by the prospect of applying the same advantage to running.

Why Power?
Whether training or racing, running is all about throttling your intensity: too intense and you will burn out too early; not intense enough and you won't achieve maximum results. There are a few possible metrics to help you throttle your intensity already:

• By feel: Feeling is a notoriously poor metric of intensity as it is very inexact. Even seasoned runners' feelings are biased by mood, time of day, stage of the run, and myriad other subjective factors.
• Pace: Pace seems like the right metric since, after all, the goal of most running training is to be able to run faster. In flat environments under controlled conditions, pace is indeed pretty good. However, once you introduce varying terrain into the mix, pacing goes out the window. Try to maintain your flat pace up a long, steep hill and cry as you eventually have to slow to a walk. Try to maintain your track or street pace on a sandy beach and cry as your legs turn to hot butter!
• Heart rate: The answer to the varying terrain conundrum was long thought to be heart rate - as you climb that hill, slow to the point that your heart rate remains the same since heart rate reflects your overall level of effort regardless of topography or surface. This works well in theory but heart rate is a very laggy indicator. It takes heart rate many seconds - sometimes more than a minute - to catch up to the intensity of exercise, which makes it very inadequate as a running metric. Running by heart rate is like driving while looking only in the rear-view mirror.

Enter power. If you can measure power, you have an exact metric that provides real-time, instantaneous feedback on intensity. Measuring power on the relatively simple mechanical device of a bicycle has been easy but running humans are much more mechanically complex and measuring power on them was elusive - until now.

A brief explanation of running with power by Dr. Andy Coggan, the OG of power training:

There are now at least two running power meters on the market; I backed one of them, Stryd, on kickstarter because I liked their approach. It is a wearable 3D accelerometer that, with knowledge of the runner's mass, calculates work done per unit time (power) in each dimension. It also includes a barometric altimeter so it knows with precision how elevation is changing throughout a run.

The potential benefits of such a device are significant: training smarter with precise intensity, "normalizing" hills during runs, optimizing running form for efficiency, and running perfectly paced races. How well does it deliver? Following are my conclusions from six months of use:

The Good

• Stryd "just works" right out of the box. Put it on, enter your weight, and you are off to the races. Running with power is indeed transformative: pick up the pace or encounter a hill without slowing down and watch your numbers soar instantaneously. Try out modifications to your running form and see in real-time how they affect your power output. THIS. IS. HUGE.
• Stryd integrates with the tools I already use. It connects to my Garmin Forerunner GPS watch and is worn on the chest as you would wear any heart rate monitor (It also measures heart rate so simply replaces the heart rate monitor I was previously using.). This means that I can keep using the hardware and software tools I already know and love with Stryd.
• That said, for those who don't already have other hardware and software, Stryd's Power Center website and mobile app are quite good on their own.

The Bad

• Accuracy is not as good when running downhill. Because runners actually use power to brake some while running downhill, our power can still be quite high - vs. cyclists, who can coast downhill, using ~0 power. As such, Stryd underreports power when running downhill.
• If you want access to ALL the data that Stryd records (like power separated into all three dimensions), you have to pair it with the mobile app (because sports watches like my Garmin only support a single power metric). For some like me, who prefer not to run with a phone, that's a negative.
• There is a dearth of power training knowledge and programs out there. Running by power is still so bleeding edge that there aren't a lot of established "best practices" yet. For some like me, though, that's actually a positive, as we have the opportunity to be at the forefront of pushing new boundaries!

The Ugly

• Because most sports watches don't include power as an option for running data, you usually have to "hack" the device for it to work with Stryd. For example, I actually have to use a cycling profile to use Stryd with my Garmin Forerunner 920XT. After my device syncs I then have to go into Garmin Connect and manually change each Stryd activity from "cycling" to "running" and I miss out on some of the running dynamics data - even though the Stryd records that data, it just isn't displayed because Garmin thought the activity was cycling, not running. While this aspect of using Stryd was annoying at first, I don't even notice it now and I'm sure that it will go away as companies like Garmin and Polar modernize.

The Amazeballs

• The most pleasant surprise of all with Stryd has been the team! They are amazingly customer-centric, responding in minutes to any challenges or questions we early adopters have, engaging us in rich discussions about the data we collect, and even involving us in the decision-making process for future. Their product improvements come frequently, often as a direct result of user feedback. If you want to see some of this consumer engagement in action, check out the Stryd forums.

A couple of week ago, I even had the honor of being Stryd's facebook group featured user. This meant that I posted every day about different ways that I used Stryd to run with power. I'll replicate some of those posts here on this blog in the coming days.