Review: Stryd, using power as a way of gauging your run
Not everyone wants a fitness tracker or smartwatch strapped to their wrist. And although it is true such devices are the most popular in the category, wearable tech companies are increasingly looking elsewhere.
Feet represent one such opportunity. After all, this is the most logical place from which to monitor steps, distance and other associated metrics. Nevertheless, it is clear the race to make your footware smart is lagging behind.
Stryd wants to change that. The lightweight shoe-clip brings an entirely new metric to the world of running – power. Cyclists have been using this type of info for a while now, so its not news to them. But it is for runners.
Essential reading: Top fitness trackers and health gadgets
Stryd accounts for terrain, form, and fatigue to tell you how hard to move. Simply set a power target and run to see results. The promise is that it will help you tweak your pace helping you go strong without hitting the wall. There are other metrics, too. Think of it as a running pod on steroids.
I’ve been putting Stryd through its paces over the past month. So does it deliver? Here’s my take.
In the box Stryd arrives with the sensor unit, charger and two shoe clips. There is also a little instruction booklet that walks you through the basics.
For more detailed info head over to the support pages of the website. Here you’ll find a guide on getting started, FAQ and more. As a novice to the world of power I found the Stryd website very helpful with setup and getting to grips on the science behind the metric.
The brains of the unit are in the black, tear-shaped main unit. To use you’ll need to secure it to one of your running sneakers. Simply place the shoe clip underneath the laces and snap the little pod in place. The thick end should be facing towards your shin with the flat bit pointing down.
Stryd is very lightweight (7 grams) so you’ll hardly notice you’re wearing it. This is good because it doesn’t impede with your performance in any way. The danger is, of course, the unit will fall off. Being so small in size, I would it imagine it would be close to impossible to find it. And I have to admit, at the outset I was a bit paranoid this might happen. But thankfully, the clip holds everything securely in place. I’ve run on all varieties of pavement, grass, dirt and the little pod didn’t budge from its place.
The company also made sure the gizmo is rugged and can cope with the elements. Its splash-proof (IP67 compliant) so running in the rain, snow and other challenging environments is no problem. However its not designed to be ran in streams, rivers and mud. This is because that water can be forced into the device since the pressure can be more than its designed to handle. So you might want to step around those puddles or choose a different route.
Walking or shaking the unit will jar it into action. You can use it with a compatible smartwatch or the accompanying app on your smartphone. Stryd plays nice with the Apple Watch, a range of Garmin sports watches, some Polar and Suunto devices and more. The full list can be found on this link. For the purposes of this review, I paired it with the Garmin Forerunner 935.
Alternatively you can use it on its own and it will keep tabs on your power data and distance (based on the number of steps you take). The internal flash drive stores up to 9 hours of run data that you can sync the mobile app at your leisure post run. I did not try this, however, as I was too keen to look at my data in real-time.
In addition to the flash drive, the company has managed to squeeze an impressive number of sensors under the hood. This includes an accelerometer, barometer and gyroscope. The combination of these is able to figure out your movement in 3D space. Stryd uses this data and your weight to spit out a power estimate and other running metrics.
There is no screen but there is a single, orange LED light in the middle of the pod. Its mostly off but flashes briefly when connecting to your phone or watch. If its blinking constantly, this is an indicator its running out of juice.
Charging is done on a wireless pad that’s powered with a Micro USB cord. Just place the pod on the glossy side of the charger in the center-most circle. Twirl it around a bit as if you’re aiming to hit bulls-eye with a dart. The LED light will appear and stay on until it has sufficient juice. Its not an ideal way to charge but it does the job.
Battery life is pretty impressive. Stryd will keep going for 20 hours of actual run time which means most people can go weeks on end without reaching for the charger. Ultimately I reverted to a quick 30 minute top-up every few days which kept it close to max capacity. If you do let it go to empty, a full charge will take about 3 hours.
I’ve always been into sports and have run a few marathons in my younger days. But its only during the past 9 months or so that I have started to get more serious about training again. My schedule includes three runs per week, ranging between 3km and 10km. Running metrics such as Vo2Max, cadence, heart rate zone information were all a mystery to me up until a couple of years ago. Not any more.
I’ve used a running pod that attaches to the waist before, but didn’t really find it all that useful. This is why I jumped at the opportunity to review Stryd. The promise is that it goes beyond a simple running pod.
To get started, you’ll need to download the iPhone/Android smartphone app and go through an account creation process. This ends with pairing Stryd to the phone. The setup will also require you to enter your height and weight, while the settings tab provides options such as preferred unit of measure and more. The app will check whether you are on the latest firmware version, so it may take a few minutes until everything is up-to-date.
Unlike a bicycle power meter, no calibration is needed to start using Stryd. Once you’ve set it up, you’re good to go.
What you will need to do, though, is set your Critical power (CP). There are a number of ways to do this and I opted for the simplest one which required me to enter my 5K best time in the settings section of the app. Think of CP as the highest power that you can maintain without fatiguing during an hour of running. Its also referred to as “lactate threshold” power and is used as your performance baseline.
Your pace zones will be automatically calculated from this metric. Similar to heart rate zones – there are five of them ranging from Easy (65-80% of CP) to Repetition (115-130% of CP). Its important to recalculate zones every month or so during training to keep critical power and zones up to date.
From here its fairly straightforward. Depending on the option you’ve chosen, you can now keep tabs on power during your run. In my case I’ve paired the device with the Garmin Forerunner 935. This required me to install a data field within the run mode of my watch.
This is accomplished by heading over to Garmin Express, clicking on ‘Manage Apps’ and installing ‘Stryd Power’. You can then configure the data field to show either 3 second, 10 second, 30 second, lap, or average power on your watch. After that simply scroll the data screens on the watch during your run to keep an eye on the metric.
There is also another important setting worth mentioning and that is the Speed Source. You can opt for GPS, which allows Stryd to tap into your smartphone satellite readings, or choose the internal sensors inside the little pod. This can be a useful option in situations where a GPS signal is unavailable or patchy.
Stryd says their sensors are a more accurate and consistent way to measure distance. Nevertheless, I opted in the end for the GPS option as I’ve been using it to track my runs in the past. As long as you consistently use one or the other you’ll be ok. My impression was that Stryd sensors were more generous in terms of estimating my distance than my smartphone GPS. Then again, I do live in central London where the GPS signal can be patchy.
So what exactly is power and why is it so useful?
Power is the mechanical measure of running effort and intensity. It indicates how much energy you are expending during the run and how fast you are expending it. It takes into account your speed, terrain change, form, and fatigue. In essence, instead of keeping tabs on heart rate, cadence and other metrics, you just follow a single, targeted power number from the start to finish of your run.
This gives you a consistent pacing strategy regardless whether you’re going uphill or downhill. After all, if you try to maintain the same pace on all terrain, you might find yourself hitting the wall pretty quickly. The little gizmo eliminates the guesswork and teaches you what good running form feels like in any environment – be it a treadmill, track, road or trail. And because power directly measures your work, you can compare your stats against the rest of the world.
Knowing your power is particularly important in race settings. Sure you can use your heart rate zones to pace yourself, but this is a measure of input, i.e. how you are feeling on the day. Power is a measure of output so lets you know your exact energy expenditure over the course of a run. At the end of the day, whoever delivers the highest output during the race will win.
To calculate power, the gizmo tracks your foot through three dimensional space and records the acceleration, impact, and force that is being applied. Stryd says all the calculations have been validated with high resolution motion capture systems, dual force plate treadmill and metabolic testing. There are even some third party studies that validate their accuracy.
During the run, you’ll see the power metric in real-time. I was particularly impressed at how quick Stryd is to recognise changes in terrain, your pace and more.
Post run, head over to the smartphone app to view your score. Here you’ll find the average power for your run, power by zones, graphs on trends during the session, as well as a breakdown for individual laps.
You’ll also get something called Stress or Running Stress Score (RSS). This is a single number that helps you understand the volume and intensity of your training session. Now you have a measurable way to quantify your effort, and use it to organize your training around important races.
Stryd has thrown in a few more metrics derived from power. This includes Form power and Leg Stiffness.
Form power quantifies the amount of power used to maintain the runner’s individual form, but is not put towards the metabolic cost of running forward. A decline in this number (at similar training speeds) is an indicator you are improving your running economy. You can use it, for example, to see how your running economy changes with fatigue.
The other metric is called Leg Stiffness (LSS). This measures the stiffness of the muscles and tendons. Think of your leg muscles as a spring. The stiffer the spring, the less energy it takes to propel yourself forward. Increases in LSS correlate with improvements in your runing economy. Most athletes range from 6 to 14 kN/M and I’m glad to say I was towards the top of this range.
It might all seem a bit confusing at first and that’s because it is. It takes a bit of time to wrap your head around all of these new metrics and for the info to sink in. Most runners will not be familiar with power as a way of gauging their runs.
Run dynamics and more
But those series about running will be familiar with run dynamics. This is data that lets you know how your run form is improving. And Stryd spits out a few stats for each session including cadence, vertical oscillation, and ground time. I won’t go into them for the purposes of this review as most runners will know what they’re about. All this data, also makes its way to the Garmin Connect app in the form of charts.
In addition to this the system provides training plans. In the month I’ve been using the device, I did not make full use of this but can see how it can be beneficial. You get personalised training zones that guide you to improvement and make workouts manageable. This includes anything from training to a 5K race to an ultra-marathon.
While the app dishes out fairly comprehensive information, you will miss out if you don’t log regularly into the Stryd PowerCenter. This is where everything really comes to life.
The Analyse tab provides you with a wealth of info illustrating the minute details of your workouts. This includes graphs that allow you to combine power metrics and run dynamics, maps of your runs and more.
The Improve tab gets more serious about analysis. You’ll get advice on what aspects of your training to work on. For example, I was told I had most potential for improvement by doing weekly long runs, Aerobic Threshold Tempo runs and training at my race pace. Its essentially as if a virtual coach was providing you with advice.
The Runner Profile gives you an overview of your strengths and weaknesses. Then there are charts illustrating your trends in metabolic fitness, muscle endurance, muscle power and more. You’re also able to compare your workouts to training plans developed by expert coaches and exercise physiologists.
Probably the most interesting of the lot is the training power heat map. This is a visual description of your running history in terms of power and duration. It overlays info from all your runs on top of each other, providing you with a map of what you are able to achieve in terms of power, duration, and frequency. This essentially gives you a very good idea what you can achieve in race conditions. Stats lovers will feel right at home.
Check out some screen-shots below.
Stryd is a unique little gadget. I’ve used running pods in the past but found that the info they spit out grows old very quickly. With Stryd I can’t help but feel I have only scratched the surface of what the little wearable can do. I would describe it as a running pod on steroids.
The gizmo will add a whole new dimension to your training. I particularly enjoyed the fact that rather than overloading you with stats, it provides visually attractive, actionable information you can use to tweak your training or know here you are currently at.
And of course, the single power metric is useful as a guide to gauge your run in real-time. A simple tweak in effort can keep you going strong through the entire workout or race. Stryd measures everything with high accuracy, real-time pace and distance.
Not to mention, the Stryd team seems very passionate about the gizmo. They are continually working on new features, their website is rich with information and blog posts. This is the kind of dedication it takes to make a product successful.
The only negative is that Stryd is a bit pricey. But if you’re serious about your running, or an amateur looking for some extra insight and motivation, its well worth the expense.
To purchase Stryd, head over to stryd.com. The wearable is also available in select countries on Amazon.
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