The Stryd running power sensor is among this new wave of foot-worn wearables that want to bring a performance metric long used in cycling to the running world. Alongside the likes of RPM2 and SHFT these trackers recommend power, measured in watts, rather than pace or heart rate, as the best way to train effectively and produce perfect pacing on race day.
At £199 – on top of what you’ll already have paid for a running watch – and with some very intricate sports science behind the whole concept it’d be easy to see Stryd as a product that’s only for elite athletes and very, very competitive amateurs. And it’s true you will need to care about performance on some level to want to make the extra investment, but anyone who wants to train for and run a smart marathon can benefit from running with power as a guide. Long used by cyclists to help produce consistent performance, it’s taken a while for the power tracking technology to reach a point where it can read the more complex movement of runners effectively, but it seems we’re now there and the running power revolution has begun.
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So does it work and is it worth splashing the extra cash for? We put Stryd to the test over a couple of months to find out.
Stryd running power meter: What is power and should I care?
One of Stryd’s main claims is that you ‘never hit the wall when you pace with power.’ The promise here is that when used correctly, running on power can help produce an intelligently paced, consistent performance over any distance and terrain. Stryd can help you more accurately predict your race times and take the guesswork out of setting race targets and pacing on race day. Anyone who’s ever gone out too fast and had to drag themselves through the final miles of a half or full marathon will tell you that’s a very welcome concept. If it works.
Essential reading: Your quick guide to running with power
The topline premise is quite simple: Power provides one number that tells you instantly, and in real time, how much work you are doing. This addresses some of the shortcomings of monitoring runs with heart rate or pace.
Pace tells you how fast you’re running but it won’t reveal the physical price you pay for doing so. Heart rate reveals how your body is responding to the work you’re currently doing, but is subject to a range of external influences such as heat, stress, tiredness or dehydration that can all affect your heart rate reading but without necessarily meaning your muscles are working harder.
Power, on the other hand, actually measures the work itself, right at the source. It’s an objective assessment of the actual output of each step and that means whether you’re running up hills or you’re a bit stressed you can run to a consistent output.
Using power is just as simple as running on pace or heart rate, or possibly even more straightforward.
You simply calculate your target power (more on how easy it is to do that later) and run to one single number for the duration of the race. This number will enable you to run just below your threshold, meaning you should be able to maintain that level of output for the entire race.
During the run Stryd sends your power reading to your compatible running watch (there are smartphone read outs over headphones too via the app) so you can ensure you’re maintaining your target pace. That’s all there is to it.
Stryd running power meter: Design
The Stryd sensor is a small black pod that clips onto the laces of your running shoes much like some race timing chips you see at major marathons.
It’s extremely lightweight compared to something like the Arion running sensor and there’s a neat, secure cradle that holds the sensor firmly in place so that once it’s on you’ll forget it’s even there.
It’s quick and easy to transfer between shoes and you get a spare cradle clip in the box, which is handy if you’re switching out footwear a lot as this is the one bit that could potentially get lost.
Inside each 10g carbon-fibre enhanced sensor lies three accelerometers that measure the acceleration of feet in three directions: horizontally, vertically and laterally. A clever algorithm takes this data and applies complex physics to accurately assess the power exerted in each step along with other running metrics such as distance.
It’s also Bluetooth and ANT+ compatible, and broadcasts in dual ANT+ and BLE channels simultaneously to maximise compatibility with emerging platforms like Zwift.
Thanks to that carbon-fibre-treated coating it copes with most knocks. It’s also water resistant and happily dealt with running in wet and rainy conditions and through the odd puddle.
In addition to the sensor, in the box you also get a micro-USB powered wireless charging dock that’s a little larger than we’d really like but is light enough to be travel-friendly and nicely moulded to the same shape as the sensor with curved edges.
If we had to pick fault with the design, it’d be that the sensor itself doesn’t have any LED lights to indicate it’s on and tracking or if the battery is running low.
Stryd running power meter: Getting set up
Setting up Stryd to work with the companion smartphone app is a straightforward question of pairing the sensor with your phone, adding a few personal details and you’re good to go.
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Syncing it so that you can get a power reading to display on your watch is a different matter. All watches whether Suunto, Garmin, Polar or Apple have slightly different processes to follow that vary in complexity. Stryd try to mitigate this with step-by-step guides to help you through each watch setup but it’s still a bit of a faff.
There’s no calibration required in the old sense of running a measure distance and adding information into an app, but you will need to log some miles with Stryd so that it can take a baseline. And to make the most of it you’ll want to do what’s called a Critical Power Test. It sounds complicated but essentially boils down to doing a set run that helps Stryd calculate your critical power – the maximum sustainable power output you can maintain for a particular period of time.
There are a few ways you can do this: one track based assessment, one time based assessment or you can also put in recent 5k or 10k times. Stryd then crunches these numbers and spits out your critical power and your critical pace, along with power zones – which work much like heart rate zones in structure – broken down into five zones; easy, moderate, threshold, interval and repetition.
These zones can then be used to guide your training intensity while the critical power is used to calculate your race target power in the race power calculator.
After we’d initially set up and paired our Stryd sensor, we did have the occasional time when the app frustratingly failed to detect the sensor and we had to go through the process of making our phone forget the device and then pair it again to get it to pick it up.
Stryd running power meter: Features, training and race tools
Stryd’s features break down into two distinct areas: training and racing. As you’d expect, the former is all about using power to guide the intensity of your training sessions, while the latter hopes to help you make the most of that training once you toe the start line.
You can of course train as you normally would and then simply use power on race day.
On training runs
Whether racing or training, there are two main ways to use Stryd: direct with the smartphone app or by connecting it to your preferred running watch or training platform and having the data Stryd collects plugged into the app or web tools for that product, e.g. Garmin Connect or TrainingPeaks. Apple Watch owners can also download and use a dedicated Stryd Watch app, though we found this to be a bit buggy.
In terms of run tracking with the smartphone app, Stryd covers both indoor and outdoor runs and displays duration, miles, pace, cadence and power in watts clearly, with easy-to-customise audio updates sent via Bluetooth to your earphones.
You can choose whether to use Stryd or your phone’s GPS as the speed source – though this is overridden with speed and pace from your watch. You can also choose which audio updates you want at each mile or kilometre interval.
Post-run the app provides a full breakdown of these stats, plus a map of your route and additional metrics that include Running Stress Score (an assessment of how much you’ve trained and the variety of intensity in your training, a bit like Garmin’s Training Load), Average Pace, Leg Spring Stiffness (a measure of how well a runner recycles the energy applied to the ground), Elevation and Heart rate, though you’ll need a heart rate monitor for the latter.
You can access your training history in-app and dive into the stats for each session, but while this is pretty comprehensive and relatively easy to navigate, some screens do take time to refresh and load and there could definitely be more explanation of the key metrics in the app. Instead you’ll have to look for these online.
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Analysing your training
If you plan to use Stryd as a training tool, then then Power Center web tool is where this really comes to life. You get more insights displayed in a much more digestible format, including additional metrics such as the breakdown of time spent in each power zone and your Form Power. You can also filter all of your stats between elapsed and moving time, which is a very useful addition if you’re doing a session like track repeats where you’re not always moving.
The Power Center is also where you create training plans. There are training plans for distances including 5k, 10k, half and full marathon, each based on whether you do average or high mileage, and you can set a target race day. Your training sessions are added to a training calendar, though the presentation of this is a little hard to decipher and could definitely be improved.
The training plans don’t currently sync with the smartphone app but we’re told this is something the Stryd developers are working on.
We haven’t put one of these training plans to the test yet, but looking at the spread of the types of workout they look comprehensive and each session comes with a detailed description and a suggested power zone to follow.
The ‘Improve’ section in the PowerCenter is dedicated to helping you understand your current running profile, training status and what you need to do to improve. And this is where some sports science knowledge might help. There’s quite a lot of technical detail here which will appeal to the PB-chasers but maybe not the beginners or casual runners.
You get a runner profile that charts your metabolic fitness, muscle power and muscle endurance – stats you won’t find on other training platforms.
Broken down into a scale of 0-75+, metabolic fitness tells you how much stress your body can handle and can be used to see if you’re ready for your target distance. For example a score of 40-65 means you’re ready for a half marathon race.
Muscle power is the peak 10 seconds of power from any run and can be used to assess how your running efficiency is improving. The higher the muscle power, the better your efficiency.
Muscle endurance represents the run with the greatest overall load from each week. A graph charts the change in your current capability for completing long runs and this can be used to determine how long your long run should be each week.
There’s also a really handy at-a-glance heat map that shows you very quickly where most of your training runs fall in terms of the power output and duration. This is great for monitoring whether your overall training approach is balanced.
One feature we really liked was the Training Optimizer, a chart of all the suggested types of workout you can do with Stryd along with an overview with specific recommendations of the areas you should focus on to see improvements. Each type of session from Long Run to VO2 Max run comes with a detailed explanation of what to do and the benefits, and it’s a great way to see which gaps you need to plug without having to rely on a real-life human coach.
Stryd definitely offers something unique in terms of its approach to training insights. Much of this data isn’t available on other running platforms – however, it isn’t always presented in the most accessible form.
This is partly down to usability and navigation in the Power Centre and partly because, although Stryd has attempted to include explanations throughout the tool, there are some areas that could use a little more clarification.
Stryd running power meter: Race day
It’s incredibly difficult to pace a race perfectly. The classic mistake is to go out too fast while the adrenaline is pumping and your mind tricks you into thinking you’re always going to feel this good, that you might actually get away with running 10-15 seconds faster than your planned target pace. Inevitably this comes back to bite you later on.
We tested Stryd during a number of races, including the Race to the Stones, a multi-day 100km stage ultra on variable terrain, and an off-road half marathon with hills and compacted mud trails. In the ultra it helped us run back-to-back 50k PBs and the other race we ran our second fastest half marathon ever, despite very challenging heat and a hilly course.
Generating your target race power takes seconds. You simply input a recent race time from distances of 5k up to a marathon, along with your target race distance and then select a runner type from Speed Demon, Balanced Runner and Aerobic Monster. It’s not entirely clear what the difference is between these three categories and that could definitely be better explained, though we’re told in a future update Stryd will know this from your training history and do it automatically for you.
Hit Calculate and you get a target race power. What you won’t get is an indication of what time you’re likely to get if you run to that power. This is because Stryd’s philosophy is based on the idea that “time is not in the control of the runner. A runner can only control their power output during a run. Any predicted time may mentally limit or push the runner to something they are not capable of and may force them to think they should deviate from their power target.”
It’s an interesting philosophy that in our tests seemed to bear fruit. When we ran based on power alone and ignored time, running to one number simplified race day. You end up running the race your training deserves rather than being misguided by ambitious targets you might not be capable of.
The only time you might deviate from this is if you know the weather is going to be extremely hot or there are lengthy downhill sections where it’s necessary to lower the power target (you use less power running downhill).
During our test races the data streamed consistently and uninterrupted in real time to our watch, responding rapidly to the changes underfoot. It’s almost impossible to run consistently within a single watt just as it’s impossible to run to pace to an exact second, but provided you’re staying close to your target and your average power each mile is on point, Stryd has some huge physical and psychological benefits.
Because power is calculated at the point your foot strikes the ground, Stryd also encourages you to pay much more attention to your form. To generate the correct power requires good form perhaps more than pace. It’s possible to run fast with bad form for periods of time but it’s harder to maintain good power with bad form.
And because you never break your threshold, we found we ran the smoothest half marathon we’ve ever run. There was no grinding it out from mile 10, in fact we felt stronger as the race progressed and passed people throughout. There’s an argument to say we could have pushed harder, but this always comes with the risk that you’ll blow up – and what Stryd gives you is the power to make that choice later in the race because it keeps you honest earlier on. That makes for a far more enjoyable way to race.
Stryd running power meter: Syncing and compatibility
Stryd is compatible with a wide range of popular running watches including the Garmin Forerunner 935, Fenix and Vivoactive, Suunto Ambit and Spartan and the new Suunto 9, Polar V800 and the Apple Watch Series 2 and 3. It also plays nice with training platforms including Zwift Running, TrainingPeaks, Garmin Connect and SportTracks.
How you get your power stats to appear on your watch or sync with your preferred training platform varies, but it will take some technical jiggery pokery that’s not entirely seamless.
For example, to get Stryd to appear on our Garmin Forerunner 645 we had to download a specific Garmin Connect Stryd app, sync that to our watch and then customise the in-run watchface fields to show power as a metric. For the Suunto 9 it was necessary to go into the Movescount web tool to set up a bespoke sport profile, with a dedicated field for power, and then sync that to the watch. So this will take some faff but it should only need doing once.
In order to import data from Garmin Connect or Suunto Movescount it’s then necessary to go into the Stryd Power Center and connect each service manually.
The same process needs to be followed to set up Stryd to export data to Strava, TrainingPeaks and services such as Today’s Plan. It’s also not currently possible to connect Stryd direct with the Strava app to add power as an in-run metric.
Even once we’d done this we had some sync issues where our Garmin didn’t automatically sync our run data back to the Stryd app or Power Center and on occasion we had to download FIT files from Garmin Connect and re-upload them into Stryd, which is a bit of a chore.
Stryd running power meter: Accuracy and battery life
One of the big claims Stryd makes on its website is that the calibration-free sensor is more accurate than GPS. This is certainly true if you’re running in areas where GPS can be patchy because the footpod doesn’t drop in and out.
In our tests, where we compared Stryd to a Garmin Fenix 5 Plus, a Polar M430 and the Suunto 9, we found it to be highly accurate in calculating the total distance.
When it comes to battery life, Stryd’s official figures claim one month of run time on a single charge with an LED light on the device that should flicker when you're running low. Although we struggled to spot it on most occasions.
You can see battery status by firing up the app, though you need to have your phone near the sensor, go into settings and hit Pair Device to see the battery icon. This is also a graphic without a percentage, so it can be hard to suss out how long you’ve got left on your pod. Also if you have pairing issues it’s not 100 per cent clear if that’s due to a dead battery or not, so this could be improved.
- Takes the pain out of pacing races
- Unique performance insights
- Good compatibility
- Some syncing issues
- No battery life indicator
- Training plan presentation is clunky