Running with power - All things Stryd!
Calling all Stryd current, past and potential users!
It’s been a while since the last thread on running with power. A few months ago Stryd released its newest model that takes wind into effect. This week they did a huge update to their software analytics in the Power Center.
It’s time to update the conversation.
It looks like Stryd is here to stay. They have a growing presence in their Facebook group, TrainingPeaks and other software platforms now include run power, many top sports watches have the ability to see run power in real-time and other sports companies are now making running power meters to compete with Stryd.
I’ve been a long time wearer of Stryd products but only in the past 3 months or so have I fully opted in, dropped pace and began running with power. Not sure why I waited so long!
I’m not an expert in all things Stryd, but I’ve learned a few things along the way.
I’d love to share ideas, best practices, and information with others, If you are an expert, please speak up so we can all learn! If you are new or on the fence, chime in with questions and concerns.
My thought is to add content to this thread on a regular basis so that we can have a place to refer back to this topic over time.
So first, about me and Stryd.
I bought my first Stryd in October 2016 and had it for a year or so. Sadly my new dog ate it one day and that was that. In July 2018 I jumped back in again. When they announced the new updated version a few months ago I traded up. Until that time I had been recording power but really using pace as the primary measure of effort. After upgrading, I decided it was time to go all-in on running with power to see if it made sense. I’ve been at it for three or four months now.
I run with a Garmin 935XT and a Garmin HR monitor. I use the Stryd Zones data field for Stryd metrics and see current power, lap power and power zone on my watch. I watch lap power closely as I run. I have it set to auto lap every mile.
Software: My Garmin watch data goes to Garmin Connect which then goes to TrainingPeaks, Strava, and Final Surge. I can then pull data from TrainingPeaks into WKO.
Does Stryd give me superpowers? Sadly not. It’s a great tool that can make you smarter, but it’s up to you to collect the data, think about it and implement findings to make you a better/smarter runner.
As always, the path to becoming a better runner, in my opinion, falls into a couple of categories;
1.Consistency. Nothing beats the month after month, year after year commitment to the sport. Don’t get injured!
2. Runs per week. It’s better to run 4 to 5 times a week or more, rather than less.
3. Volume. Someone that runs 40 miles per week on a regular basis is most likely to be better off than a 10 mile per week runner.
4. Training Zones. A good training plan does wonders.
5. Data and data analysis. Write down what you have done or upload it to a website like TrainingPeaks. Learn from the past. Use technology to help collect and analyze your information. This is where Stryd fits in.
I’m trying not to write multi-page notes!
Coming next are thoughts on:
- How do I know what I know?
- How accurate is the Stryd?
- What data does it collect and what does the data mean?
- Metrics in the Stryd Power Center
- Using Stryd to look at race performance. Am I getting fatigued or is it all in my head?
- WKO Charts and Expressions
- Post-run and weekly analysis - things I think about.
Other ideas too!
tom
Comments
@Tom Glynn - thanks so much for posting this. I am a stryd newbie. I started wearing it last year (I have the footpod without the wind update) and really understand the use of power and great it is to look down at my wrist and regardless of pace which is affected by grade, wind, humidity & temp, I am putting out good power (or not).
my questions on Stryd, for now, rest in the how do you set it up?
does it require calibration?
should one use their distance calculations to be from Stryd instead of GPS when running outdoors?
when running on treadmills at the gym, should it be recalibrated everytime I am on a new TM?
can I run in Zwift just by connecting Stryd to my Zwift computer/phone/ipad?
on a more advanced level, do I start doing intervals using power zones instead of pace zones?
@scott dinhofer - thanks for chiming in!
Q. Does Stryd require calibration?
A. From Stryd "Stryd is very accurate out of the box, and calibration is not required for most runners." There is a way to calibrate the device - same way as the old footpads - take it to the track and run a known distance, but they don't recommend it. Everything I've read from Stryd and others suggests you should not calibrate it. I have not calibrated mine.
Here is the link to calibrate if you really want to: https://support.stryd.com/hc/en-us/articles/115004337834-Distance-and-Calibration
There have been a lot of discussions on Stryd versus the treadmill over the years. The end result is that Stryd is way more accurate than a treadmill and I set effort from my watch using the treadmill data as a useful guide. Lots of people have done the analysis, including DC Rainmaker and there doesn't appear to be any disagreements on the issue. Some guy did a bunch of testing with Stryd against other devices and Stryd (uncalibrated) won hands down. No one seems to dispute his data. I find it fascinating that Stryd (which does not have GPS) was way more accurate that all GPS devices. Check it out: https://fellrnr.com/wiki/GPS_Accuracy
Q. Where should the data come from?
A. For Garmin watches, the recommendations are to turn auto calibration off, the calibration factor should be set to 100, speed/pace from Stryd, distance from Stryd. If your watch has GPS then you will get mapping and elevation data will (most likely) come from the watch. It's pretty confusing as to where all the data comes from and what device takes precedent when both compute the data. All watches have different settings. I've followed their device suggestions. Someone wrote a pretty good article on it a couple of years ago and it keeps getting updated. Here: https://support.stryd.com/hc/en-us/articles/360002439534-Garmin-Watches-Pace-Distance-Cadence-from-Stryd-vs-GPS
Q. Zwift
A. I don't use my Stryd for Zwift but lots of people do. It's time I did! I'll report back later on this.
Q. Should I do intervals with power zones instead of pace?
A. Yes. I'll write more on this on another post, but I've switched to power based running completely. It really mirrors my bike training. I bought my first bike power meter in 2004 and it took me a long time to get rid of speed on the computer. Now I wouldn't think of looking at speed on my bike in order to gauge effort, but that was a leap back then. Same with running. In order to get it to work you need to benchmark with a test, decide how to set zones (Stryd can auto calibrate your critical power and update zones if you want - I don't let it). Someone noted that zone training should be prescriptive, not descriptive. So running in Zone 3 is descriptive but not that helpful. Running at 80%-82% of CP really helps dial in the training. I'll write more on how I'm figuring out zone training shortly.
Tom
I'm also a Stryd user, i and love my pod. I never recalibrate and the battery if pretty impressive. I bought the pod initially for indoor running as i found both my Garmin 920 and the Treadmill to be very inaccurate. It's only for the past few months that i'm switching towards run with power instead of with pace or HR so i don't have much to share there yet except that i's a bit of a cultural change which is not easy at first (slow down on hills and go faster on downhills).
The only issue i have with my Stryd is actually related to Garmin and not to Stryd itself: when i run on Zwift with Stryd, my run is pushed to Garmin and FS and Strava but there is no connection (i think) between Zwift to Styrd Powercenter and i was hoping Garmin Connect would then add as a middleman and push the data to Stryd Powercenter but it does not. If i use Garmin to record the run then the data is pushed to Powercenter but not if it comes from Zwift first. So i have to push the data manually by exporting the .zwo file form Zwift and importing it into Powercenter.
In the grand scheme of things it's not a big issue and clearly does not outweigh the great benefits Stryd offers. Highly recommend it.
Subscribed! I've been using a Stryd for a couple of years now, but I wouldn't really consider myself an expert. I'd love to hear from others here. I will make a couple of comments though:
@Vincent Sivirine Yes, I also found that Zwift won't push to Stryd powercenter, but you don't need to manually upload files. Just go into Powercenter, select the device and do a sync. It will then download the run data directly from the Stryd pod into Powercenter.
For running in Zwift with Stryd, I did do the calibration routine to calibrate the Stryd to my treadmill so that Zwift reports the same distance that my treadmill reads, but that's just because I'm OCD and it would really bother me if those were different. What I really care about is power/duration, so whether it was 5.2 or 5.5 miles is somewhat inconsequential in reality. If I was running on different treadmills in different gyms I definitely wouldn't bother.
One question for anyone that's come across this... I've noticed that if I'm running in Zwift and I also have my Garmin 935 running so I can see power (why, oh why can't Zwift show power when running like in cycling mode?!?!?!? 😫) when the run is over and Zwift uploads the file to TP and Strava the power data is missing. I'm guessing that the Stryd will only send power data to one device at a time, so when I'm running in Zwift with no Garmin I get power in the file, but with the Garmin running the Zwift file has no power. Anyone found a solution to this? I currently end up downloading the file from the Garmin or from Stryd Powercenter into TP and deleting the Zwift file, but that's annoying to have to do that after every TM run.
thanks @Tom Glynn
great questions @scott dinhofer
Love it for racing IM by power but have yet to make the jump to power intervals but thinking about making the switch.
Thanks @John Katsoudas, you're correct, i did not think of this before, it's indeed much easier to get the data from Powercenter connected to the pod directly.
On your issue related to running with your Garmin on Zwift and your power data only going to Garmin, why do you also record your run on your Garmin? if you don't, Zwift will record the power data (but i agree with you, does not show it while you're running which sucks) and then will push it to Garmin Connect, TrainingPeaks etc.. with power data included. So why also recording your run on Garmin?
Hey @Vincent Sivirine I have the Garmin on when doing intervals paced by power so I can make sure I'm hitting the power targets. When just doing a TRP run I don't bother with the Garmin because I have a good sense for what TRP pace is on my treadmill, but when doing intervals I like to be able to actually see power.
Getting to Know Your Stryd
First, how much do you really need to know after purchasing your device? I’d argue, not much, especially if you already have a power meter on your bike and understand the basics.
Sure, there is more to clipping it to your shoe and collecting data but I don’t believe you need a math degree or hours of time to deep dive into all the nuances of running power. With a small investment of upfront time, scanning for what’s new occasionally and spending a few minutes a week looking at reports and analytics and you should be good to go.
Here’s where I’ve gained most of my Stryd knowledge. If you have other great sources, I’d love to know!
A quick caveat: Stryd hasn’t been out that long. They have had three hardware platforms, multiple software updates. As it gains traction lots of smart people are piling on and sharing what they know. So, any information more than a year or two old should be confirmed with more current data. What we know increases daily and it often refines older ideas.
Best place: Stryd. Their blog is awesome. Well written and not too technical. I subscribe to it and get regular email updates that I flip into Evernote.
Stryd on Facebook. Join their group. They are on it all the time. Love the moderator, Gus, who starts every comment with “Great question”!
Stryd Power Center. I just updated this week. Really impressive data analytics for all your runs. Lots of information icons and generally really well laid out. I’m still digesting it all. They just did a couple of Facebook Live videos walking you through everything. Worth the time. We still need to figure out how to separate all the marathon data analysis from a more triathlon friendly perspective.
Stryd website. Their knowledge base is deep and has a great FAQ section. The site is searchable through Google and other search engines. They have a chat window which I’ve used before. Fast and easy. They also encourage you to call them if you need to. Over the top customer service.
Steve Palladino. The smartest guy I’ve found on the topic. Former Olympic level marathoner, podiatrist, and all-round Stryd expert. Follow him and his Palladino Power Project on FB. Content varies from easy to understand to quite complicated. Not sure I fully understand his complicated race prediction spreadsheets or how to modify them for a triathlon!
Books:
Run with Power by Jim Vance. This the first book out on the topic. Easy to read. Slightly outdated
The Secret of Running: Maximum Performance Gains Through Effective Power Metering and Training Analysis (Meyer & Meyer Premium). Pretty technical but the best book out there that I know of.
What have I missed?
Hello, I don’t use Stryd but I use the Coros watch and power meter. It gives me great info, but I don’t know what to do with it.
What are good power numbers?
it suggests I do a lot of vertical running, but how do I change that?
If I share some data here, can you tell me how I am doing?
Thanks! Very happy to see this post!
@Virginia Edmonds Happy to help if we can! First, I’m not familiar with your Coros watch. I did a quick search on the web and see they have a variety of models. Can you send a web link? Also for the power piece, any info you could send would be helpful. Do they have their own website to look at data or do you import it into a 3rd party program like TrainingPeaks?
Stryd Power Center generates a bunch of interesting metrics, which I plan to cover soon.
After looking at your watch info I’ll add more thoughts and see what others think too. Right off the top though, my power meter works really well on a treadmill. I always trust my Stryd data over the treadmill. It’s pretty interesting to see how the various treadmills at the gym are all off and just not calibrated. They can be off 10-15 seconds per mile at an 8:30 mile.
Also, even for mildly hilly courses I know run with even power rather than even pace. My long run today was 230W +/- a few watts every mile where the pace went from 8:23 to 9:04 per mile. Last year I would have run at the same pace throughout.
I’d love more info on your need to do more vertical running. Stryd has a metric called leg stiffness that can be improved with more hill running.
Also, maybe a few thoughts on your current training style. If you go out for a long run do you look at pace or zones. How about faster stuff?
I’ll go over some of the Stryd metrics, how I use or don’t use them and how they can be improved on.
Tom
Getting Up to Speed with Your Stryd
I think I was like a lot of Stryd purchasers. Buy it. Clip it to the shoe. Run a lot. Wonder what else I should do. Unwilling to let go of other measures of effort like pace and heart rate.
So, what are the next steps?
For me, a couple of things from easy to a little bit harder.
Benchmark your fitness with a CP test
There are plenty of ways to benchmark your running fitness. The Stryd test is simple and repeatable. Here are the instructions for doing their 9-3 test. https://support.stryd.com/hc/en-us/articles/360006974493-How-can-I-calculate-Critical-Power-manually-
Stryd can automatically calculate your CP number. On your phone go settings/critical power/ and select Auto-Calculate.
My suggestion is to do a couple of manual tests first and then slide over to the auto mode if you think the calculations are reasonable.
Once tested, go back and do it again once in a while. This is a great measure of current fitness.
Of course, the next step is how to get better!
Set Training Zones
Same idea as HR and pace zones. See here: https://support.stryd.com/hc/en-us/articles/360039774153-Power-Zones
I tend to use slightly narrower percentages of CP to get a little more granularity but that is a personal preference. All my training now is done with run power zones. I no longer use pace or HR goals.
Compare your current self to your theoretical best self
Stryd’s new Power Center is excellent. One of the best graphs is the Power Duration Curve (PDC). It shows best effort (in watts) over time for a given time period. In my graph above I have it set for the last 90 days. The dotted line shows your best efforts. Hover over the 5-minute time area and it will show your peak power. This is a great way to get a quick overview of your best efforts.
The white line is your modeled ability - a Stryd algorithm that guesses your best possible potential. The better the data, the better the Model Curve. It only takes three runs to establish a valid Model Curve (MC). As long as you log quality efforts in the 10-30 second range, 10-20 minute range, and 50+ minute range, your chart will be accurate.
https://support.stryd.com/hc/en-us/articles/360041644594-Auto-calculated-Critical-Power-Model-Curve
One method to improve your Critical Power (CP) is to look at the graph above and note areas where there are large gaps between the two curves. My biggest gap is in the 10-60 second area and then the 10 min-60 min section. To improve your CP potential, try and make those gaps smaller. Decide one day to go after a small segment of your curve and try your best to lift your PDC to get closer to the Model Curve. The closer they are together, the fewer weaknesses you have and the better all around runner you are.
I will do this in the off season and other times when not building for a race.
This chart can also help you set interval power targets. For example, let’s say you want to run 3 x 10 minutes hard. How hard should you go? I’d take a look at my PDC curve to see my best effort for 10 minutes over the last 90 days. Then look at the best efforts for 30 minutes (total time running hard 10x3 min). You can probably run close to your 30 minute effort because it’s going to be broken into intervals, but you probably can’t run your 10 minute best effort 3 times in a row. You can then estimate a power level, say 90% of your best 10-minute effort. If it’s too easy or hard, adjust accordingly.
Compare yourself to other Stryd users
Stryd has a cool little chart that lets you compare yourself to other users that are similar to you in gender, age and planned event.
Here is mine:
I’d take this as interesting but don’t change what you are doing based upon what you see. I’m higher in almost every category than the average Stryd user, but I’m 8 weeks out from my Ironman. Most are probably doing later dates. Also, other users may be in the wrong category. Maybe they were training for a marathon, but now they are done and are focusing on 5Ks. If they don’t change their preferences in Stryd it would look like they were doing a ton of speedwork for a marathon. If a lot of users were not categorized properly, Stryd may be telling you that you need to do more speed work to be like the others, when in fact, you may be right and others wrong.
Again, the new Power Center does a great job with descriptions. Just click on the arrows to the right of the categories and they will give you suggested workouts with their descriptions to improve in each of the categories. So for example in Fitness you will see this:
Look at the various metrics produced by Stryd
I’ll talk more about metrics in other posts, but you should be aware of a lot of metrics that can potentially give you some insights into your running.
Metrics include the following:
*power
*pace
*form power
*ground time
*vertical oscillation
*air power (in the newest Stryd version)
*running stress score
*running effectiveness (the ability to turn power into speed)
Steve Palladino has a great document with in depth analysis of many Stryd metrics here:
https://docs.google.com/document/d/e/2PACX-1vSS2mB3I3M_193Al8Kx02fSuDrK9uS8zJLqKv5WSQPcCEgPh19RPxMMbzk7OxKg3-A2QZkQ6_vDLR0q/pub
I’ll talk more about each of these, but thought I’d throw out a couple of thoughts on a few.
Cadence. There are a lot of different thoughts on cadence. Why do most great runners run at leg turnover at or faster than 180 per minute? Does faster turnover make you a better runner or do faster runners develop faster turnover with years of training? Should you focus on running form, including cadence?
I tend to look at cadence over time. I created a WKO chart that plots my cadence when I’m running (but not walking).
I put in a line at 180 rpm and then each dot represents my average cadence on each run. You can see that my cadence has been falling since early February. Am I starting to fatigue as I build into my IM? More thoughts on this later.
One of the more thought provoking posts I read was by Steve Palladino where he used Stry metrics to figure out why one of his athletes was imploding during a workout. It’s called “Analysis of “struggling” in a run workout”
https://www.trainingpeaks.com/coach-blog/using-wko4-to-analyze-the-struggle-in-a-run-workout/
More later!
Tom
Great stuff in here , thanks @Tom Glynn , I really do enjoy using my Stryd and analyzing the data, I was going to upgrade to the newest version(for wind), but they still haven’t made it water proof, and it’s probably even more difficult with the wind version (pitot tube), but it just doesn’t make any sense for Trail Running with water crossings. I have actually swam with mine (on my shoe and inside my wetsuit) and the occasional water crossing without removing it, but if I have a known course with lots of water crossings I just leave it off. Maybe someday they will make a trail version.
@tim cronk agreed.
First, I have to ask....why would you wear shoes in a wetsuit?? 😂
I don't do any trail running but there is chatter on the FB group about it. Gus, the moderator recently stated "Stryd is very water resistant, however it is not 100% water proof. This means you can run through puddles, in the rain, and rinse Stryd in the sink. But, you should not run through streams, rivers, or oceans as these are high pressure environments and risk damaging Stryd.I recommend to temporary remove Stryd for these conditions or stepping over them or with the foot that Stryd is not on.
More comments, all saying the same thing: https://www.facebook.com/groups/strydcommunity/permalink/2325333417764709/
(You probably have to be a member of the group to read it.)
Hi Tom! Thanks for your response. I just saw it today so I apologize for the delay. I appreciate any insight and will get you the information you requested. I will post again soon!
Thanks @TomGlynn for starting this thread.
I am a WKO4 fanboy, so I have modified a bunch of bike graphs and charts, by substituting runpower for bike power. So I look at running with power exactly the same as I look at bike power training.
I am away from home this weekend so I can't give you the exact names of the charts and graphs. But I will do that when I get home if anyone wants me to. A key chart is the one that gives you the short, medium, and long time durations for informal power testing. It gives you the duration where there is the largest difference between your actual power and WKO4 modelled power. Like with bike power, if I keep the differences small between my actual power and modelled power across all durations, then I am reasonably sure my modelled run mFTP is accurate
I use Final Surge to give me my running power zones and only use power for all my runs, except race execution (where I use RPE, and heart rate as a secondary metric).
A very interesting book on running with power is by some Dutch guys called the Secret of Running. It was free and has a web based running calculator that is quite interesting.
Hopefully one of these days I'll be able to really follow all of @Tom Glynn 's advice and actually use it to potential!
Right now, all the running I'm doing is for weight management on my way to LVL100MTB, so lots of LSD.
@Peter Greagg How you have found the FS power zones relative to pace zones? I found the FS power zones to be way, way off what my Z1-Z4 paces are. I've also found the Stryd Power Zone bands to be a little too broad, but they are in the ballpark.
I went the extra geeky route and ran a regression on my run history (power and pace and some other variables) and have an equation that is bang-on for me. I update the regression about once a month. I can type in a power figure and get the pace and vice versa.
@Jeff Phillips this is indeed geeky and it's awesome! did you export from TP to get the history? is this something you could share?
@Vincent Sivirine I had to manually input data (date, distance, time, avg watts, Treadmill or outside, and RPE) into excel, then run the analysis.
There is a stats package called "Stata", but you can also do simple regressions in excel.
@Jeff Phillips I purchased a Steve Palladino marathon plan that I loaded into FS just to get an idea of how he trained his athletes using power. He also has his own zone system, which is a little narrower than Stryd.
Palladino zones for me (CP = 301W)
Entire Workout
Zone Name Power Percent
1a Post-Interval Recovery 151 to 195 50 to 64.9
1b Easy Warm-Up 196 to 225 65 to 74.9
1c Easy Aerobic Running 226 to 241 75 to 80
2 Endurance/Long Run 241 to 265 80.1 to 87.9
3a Extensive Threshold Stimulus 265 to 286 88 to 94.9
3b Intensive Threshold Stimulus 286 to 307 95 to 101.9
4 Supra Threshold 307 to 319 102 to 105.9
5 Maximal Aerobic Stimulus 319 to 349 106 to 116
6 Anaerobic Power Stimulus 349 to 451 116.1 to 149.9
7 Sprint/Maximal Power 452 to 150 to
Stryd Zones are:
Zone 1 Easy
65 - 80% CP
195 - 240 W
Zone 2 Moderate
80 - 90% CP
240 - 270 W
Zone 3 Threshold
90 - 100% CP
270 - 301 W
Zone 4 Interval
100 - 115% CP
301 - 346 W
Zone 5 Repetition
115 - 300% CP
346+ W
My long runs are done around a 230W range, putting me in 1c - easy aerobic for Steve and Zone 1 easy for Stryd. Typically you would think long runs should be Zone 2, but my guess is Stryd and Steve are running zones, where we would temper the pace because we do a swim and a bike first :)
Should I be running harder on long days??
Tom
@Jeff Phillips your regression analysis intrigues a data guy like me! Out of curiosity, do you run the same courses all the time? I would think it would be hard to correlate power and pace if sometimes you did flat and other times you did hills. Do you factor in elevation or run separate regressions?
Tom
@Tom Glynn The Palladino plan looks interesting. So do you apply those zones to the EN workouts?
I live in Minneapolis and the vast majority of my running is on flat ground. To keep things simple, I'll take the noise in the data if I have some workouts where I run hills. Also, any 20-30" hill repeats are normally a small part of a run when I do them that they don't impact the avg. power figure that much.
If you have the ability, it'd be interesting to see what a regression on your own data would like compared to Palladino's zones.
@Jeff Phillips I actually have been influenced a lot over the past few years with Stephen Seiler's research. He tends toward a three zone model, so I take other models and then try to conform them to his.
He looks to a lower inflection point that reasonably coincides with upper end zone 2 for most of the training zone models. Metabolic testing would give your ventilatory threshold 1 (VT1) about the same effort and lactate testing would be around 2 mmol. All close, but not the same. On the upper end it would be right around CP/FT, VT2 or 4 mmol.
Lots of nuances, but Seiler recommends mostly Zone 1- Zone 2 stuff below VT1 and then some at or above CP/FT. Palladino's approach is lots of easy, some mid point tempo stuff and then some just below, at , or just above CP.
I rethink my run strategy every year or so. 3 or 4 years ago I did quite a bit of fast running in the 5K range. It helped my Half IM speed but not much if anything for my IM times. Last year I decided to become an expert at running IM pace and almost all my runs were Zone 1 or Zone 2. I was the fastest runner in my AG at IM Texas, but my half Ironman run times were miserable. Starting in November or so I decided to go all in on power to dial in effort a little better and use some of the Palladio workouts early on before my IM build. Once Texas is done I'll go back to some of the faster stuff. He has big blocks in the 90% of CP range and some in the 95%-102%, with long runs in the 80% to 85% range.
@JeffPhilips When I said I use Final Surge to calculate my zones (based on my run mFTP), I followed Coach Patrick's advice and used the Endurance Nation drop down menu selection.
The zones seem reasonable to me. Zone 4 is where I think it should be etc.
Stryd Weight, Watts & Watts/Kg
@Tom Glynn Great thread - thanks for starting it.
One thing that is pretty important with Stryd is "Stryd Weight." The foot pod doesn't measure power, it measure watts/kg and uses the Stryd Weight that you set to convert from watts/kg to watts. The implication of this is that if you change your Stryd Weight setting, you will change the power numbers you see on your next run relative to what you would have seen if you didn't change your Stryd Weight setting.
Because of this, it is considered best practice to either: 1. Never change the Stryd weight setting, or 2. Only change your Stryd Weight setting at the beginning of a training block (eg, start of season).
If you update your Stryd Weight setting, it will be very difficult to measure progress, compare one run with another run or to know which powers to target during a run.
I have not updated by Stryd Weight setting for several years... it is not within 25 pounds of my current weight. But - that doesn't matter to me, because I know what my power targets are / have been and I am able to compare runs year over year.
Another implication of Stryd measuring in w/kg and everyone having different Stryd Weight settings is that comparing numbers from one person to another is pretty useless. 300w for me and 300w for you really doesn't tell us anything. if you want to see how you compare to others, this can really only be done on a w/kg basis.
Bottom line on Stryd Weight: Set it - don't change it!
While I have not thought about changing the Stryd weight very much, I do change it when my weight changes.
I am mid season and had to have 7 months of no training between jan and July last year. I am 11 kgs lighter now than when I started training in July. It doesn’t make sense to me to not change my weight as it changes.
In relation to comparing my run FTP to others, IMO it is the same as for bike power. I did 6:20 bike split at IM Western Australia on Pnorm/Pav around 112 watts. This suggests that my power tap hub reads low, but I don’t care as long as it remains precise over the season.
To me the important thing is to set you run and bike FTP close to what they are based on recent testing and set your different training zones on that so you can maximise the benefit from EN’s excellent training plans.
Just my two cents worth.
@Peter Greagg - I think your logic when comparing your bike FTP setting and Stryd weight is flawed.
Conceptually, I agree 100%. You want to work with a meaningful FTP on the bike and a meaningful CP with Stryd.
The easiest way to have a meaningful CP on the Stryd is to leave the Stryd Weight constant so that changes in CP are driven by run training adaption, just like bike FTP changes are driven by training adaption.
Here is an example, let's say your weight is 75kg and you do a CP test and your new CP is 300w. a week or so later you repeat the exact same CP test and you run the exact same times as previously. However, your weight has dropped to 73kg. Base on this new weight, Stryd calculates your CP to be 73kg/75kg*300w = 292w.
Your performance did not change at all. But now you have a lower CP and you have to recalculate all your zones to lower numbers.
From my perspective, changing the Stryd Weight did not add any value to my training. In fact, it may have detracted value because now I am targeting lower numbers. This is why the majority of Stryd users in the running community do not change the Stryd weight during training blocks.
Leaving your Stryd Weight constant and updating your CP regularly (just like you mentioned with your FTP) is analogous to keeping an accurate FTP on your bike.
Having said that, If you still wish to update your Stryd Weight, you make sure that you also:
@Rich Stanbaugh Thanks for the weight explanation and example. I had seen a couple discussions about it on their FB group but it didn't make much sense to me. Your small example is perfect.
@Rich Stanbaugh
i am a really geeky data guy so I can't just leave it. When my run FTP changes, I change all my zones. Also, I use the same weighing protocol every time and weigh before the FTP test.
i really want to know that my training is changing my FTP (hopefully for the better) rather than "just" loosing weight LOL.
@Tom Glynn thanks, yes I am a member of that FB group and follow along, I know the STRYD guys are well aware of the issues NOT being water proof, I'm sure they would make it so if it were easy , there are 3 "sports" that are growing fast and could use that update, Ultrarunning , SOS branded triathlon , Otillo SwimRun, all of which I have participated in and require WET FEET :-)
Reference the not updating your weight because its a calculation vs. strain gauge is the same issue I always had with " bike FTP" . At least , thanks to the use of zwift ,the cycling community is now speaking more correctly IMO in the terms of w/kg which changes daily based on power and weight. I do set and forget my STRYD weight , but it sure would be nice if the w/kg was correct daily not only when your weight happens to be what your input is. Not a perfect system but its all we got for now, maybe some day we'll see an affordable running strain gauge.