STRYD Critical Power Estimating/Racing Estimate Data
Now that we are completely confused with the recent "Does Functional Threshold Power Really Matter" thread. I figured it was time to dig into STRYD data. I am new to running power, however I was an early adopter of the original STRYD before it was ready for prime time, it failed a few times, they replaced it , I gave up. They have come a long way since then and jumped back on board a few months ago. Having done lots of just running, some tempo, and interval work in the 1/4 mile to 1 mile distance (3-6' of data) and recently a HM race , figured I was ready to do the formal STRYD CP test and put their data and race estimator to the test.
Test - well rested and highly caffeinated to max numbers as best I could. Performed the 3' and 9' test (as prescribed via STRYD), wu was 10' then 5 x 30" strides, few minutes recovery , 3' all out , 30' rest recovery with easy jogging and walk intervals, 9' all out , cd.
Results- right inline with expected via past performance intervals
3' - 243 watts (right in line with my best 1/2 mile interval #'s)
9' - 229 watts ( past 1mile intervals 228-238 around 6' )
Punched into the STRYD CP calculator = Critical Power 222watts
Going to the STRYD estimator for the HM distance.
Speed Demon- 205watts target
Balanced Runner- 209 watts target
Aerobic Monster- 215 watts target
Actual Half Marathon - 221 watts for 1:28:52
Prior to running the HM I did not have the CP and HM estimates via STRYD. This is probably a good thing , having far exceeded STRYD's best estimates, and a possible example of a mental limiter. However I did have 2 RR's of 11 miles, 1st one I ran at 204 watts and held steady the entire way, feeling that I could do better, on the 2nd RR I bumped it up to just over 220 and came apart after about 6 miles and barely holding 205, the average watts for RR#2 was 214 . 204 not enough and 214 too much.... Raceday targeted 210. I was tapered, rested, and caffeinated, and felt really good, so pegged it at 220ish and held on with NO FADE for the 99 minutes.
Not sure what to do with this data. WKO is lacking in run power charts. Definitely a much flatter power curve than my bike power meter.
Hope others share thoughts and data.
Comments
Interesting data Tim.
If you change the term "power" or "bikepower" in the bike charts in WKO to "runpower", they will then display your running equivalent to the bike power ones, including an estimate of your running FTP.
I have drunk the WKO4 coolaid for bike power — According to Andy Coggan, the 95% of the 20 min TT (after 5 mins all out etc) as a good estimate of FTP only holds for 55% of athletes. So I use WKO4 to estimate my bike and run FTPs after testing at 5 secs, 1 min, 5 mins, and 20 mins over several days.
@Peter Greagg thanks for the tips in WKO4 , unfortunately all of a sudden my WKO4 doesnt wanna co-operate with me, looks like all my data is still in it and it syncs but some charts have just disappeared , so I have bigger problems with that program... I have even un-installed then re-installed... Just about spent all the time I'm willing to as well.
@Peter Greagg figured out wko4 charts again... program is horrible...
Good Primer for running with power.
https://irp-cdn.multiscreensite.com/dc479d29/files/uploaded/Running-FTP-Primer-StevePalladino.pdf
So you exceeded the CP prediction of the power you sh/could hold for 1.5 hours/21 km?
not a good argument for using "power" as a primary metric to pace a race. You imply you went with the usual RPE and exceeded "expectations". Not useful as either a whip or rein in this example.
Still holding hope for its value on a hilly triathlon long course run leg. And waiting to see if there is any value in the ultras (for you, not me, of course)
I have 15 months of data including races, and have not found it more refined than pace, HR, and RPE. But it's fun to have, one more thing to keep my mind occupied while my body does the work...
@tim cronk The concepts of FTP and Critical Power are very similar. Both are models that we can use a power meter to "give us a look inside our metabolic fitness." They have different math and are not exactly the same, but the numbers are generally not too different.
There is a really practical reason that Stryd is basing everything on Critical Power. In order to get good FTP estimates, we really need large data sets over long durations (20, 30, 60+ minutes). However, a lot of runners are focused on events that are nowhere near that long (100m, 400m, 800m, ...). Stryd used the CP model to estimate the threshold rather than using one of the FTP models because of this difference.
The big challenge that I've had with Stryd is trying to take the concepts that I understand about using power data to impact cycling fitness and translating them to using power data to impact running fitness.
The best discussions that I have found on this topic are in Steve Palladino's Power Forum on FaceBook. There are a lot of smart folks having power-based discussions on run coaching in that group. I added you to the forum (Steve approves additions). Steve is tied closely to Coggan and is an avid user of WKO4. Based on discussions/results I have seen in the forum, I suspect he is a pretty good run coach too. There are a lot of WKO4 run charts available through that group.
Here is a link to a Primer that Steve wrote on running with Power: https://irp-cdn.multiscreensite.com/dc479d29/files/uploaded/Running-FTP-Primer-StevePalladino.pdf
@Rich Stanbaugh thanks for chiming in on this thread and adding me to Steve Palladino FB group , I did find that primer and even posted it above , good stuff.
@Al Truscott yes I pretty much crushed the STRYD estimate for a HM based on the CP of 222 based off the 3' and 9' STRYD test. The best case scenario was 215 watts and I did 221 watts. I'm much more concerned about limiters than whips :-)
More observations- in running with power I suffer from the same weakness as I do in biking with power, I have baby numbers, but have the ability to hold a higher percentage of those numbers for a longer period of time. This means 2 things. I should work shorter/harder/vo2 for the bike and the run, and it also means that I have a very shallow power curve on both, but the running power curve is definitely more gradual than the bike. I have been using the CP setting of 222 from my tests and watching TSS accumulated on various types of runs from walking, road intervals, to technical trail running and feel it does the best at calculating a reasonable TSS for the activity compared to hrTSS.... Pace TSS would be totally irrelevant due to the trail running.
My power numbers below listed from shortest to longest.
3 minutes test 243
9 minutes test 229
34 minute race 227
99 minute race 221
walking easy sub 100, brisk 110 , hard 120-130
hiking same as walking but 150 hiking hard uphill
trail running - easy 130 to hard 190
@tim cronk
Where in the Stryd Power Center did you find these terms: Speed Demon, Balanced Runner, Aerobic Monster?
I've seen other references to it but can't find it.
Thanks
@Sheila Leard Its in the STRYD app, Race Power Calculator.
@Rich Stanbaugh forgot to ask - Steve Pallandino says Final Surge supports run power metrics. I could not find it within Final Surge???
@tim cronk I can't help with Final Surge... I haven't taken the plunge yet. Already subscribing to more platforms than I can keep up with!
@tim cronk - some thoughts below...
>> More observations- in running with power I suffer from the same weakness as I do in biking with power, I have baby numbers, but have the ability to hold a higher percentage of those numbers for a longer period of time. This means 2 things. I should work shorter/harder/vo2 for the bike and the run
Without a doubt, doing hard work on the left side of the PDF will lead to improvements on the right side. There has been a tendency in endurance sports to focus almost exclusively on aerobic endurance. But our bodies do not work that way... The metabolic systems are tied more closely together. Developing the left half of the PDC (anaerobic (FRC) and the VO2) leads to attaining gains in the aerobic endurance more easily.
>> and it also means that I have a very shallow power curve on both, but the running power curve is definitely more gradual than the bike.
I believe this is the case for everyone. Perhaps if we were practicing explosive running starts from the blocks, we would get steeper on the left side? I have been reading some evidence that plyometric exercises like jump squats, box jumps (up and down), skipping rope, etc lead to speed development. These types of exercise seem like they would develop the left half of the PDC and make it steeper.
There is an inherent danger to working on the left half of the PDC for running vs the bike... INJURY. It is pretty hard to hurt oneself by dumping 100% of our power into the pedals whereas all-out sprints, maximal accelerations, etc are high-risk activities (at least they are for me). The concept of using plyometrics to achieve a similar benefit is super interesting to me and I plan to give it a go this year.
As I have mentioned in some of my race reports, I find Stryd extremely useful for determining how much work is done on a particular run. It leads to much better numbers than pace for me. My pace can vary drastically on different terrain but my power doesn't.
Knowing my power numbers let me set power targets for races. I knew beforehand what power is safe and what power would be risky. I wouldn't know that with pace due to hills and different terrain types.
Power on ultras has helped me some but I wouldn’t care if I didn’t have it. It does help me try to push when hiking or trying to run later in a race.
I've used Stryd for a while. I bought into the first generation and shelved it pretty quickly. The latest version is much better.
One of the biggest issues I have is being able to monitor power consistently. On my bike, especially on a trainer, I can sit glued to the data and really focus on the power number. With running, I don't have the feel for power and I have to keep looking at my watch all the time. Power is very consistent on the flats, but tends to bounce around on the hills.
For now, I use it at the gym to set the pace, as it is more accurate than the treadmill speeds. The gym treadmills are all off a little bit, so it's good to use the Stryd to over-ride them.
For post race analysis, I've found that I really power down going up hills, so I'm working on my up and down speed/power. Again, it's pretty hard to see on the watch in real time, but it's easy to see post run.
+1 to the Steve Pallandino FB group. I'm learning a lot there.
I've played around with the data in WKO, really trying to understand if I'm consistent with power throughout a long run. With flat courses, it correlates directly with pace, so it doesn't add value to me, but hillier courses are a better way to make use of the power data.
What data fields are people using when running outside?
Tom
RE: Final Surge: I've been noticing over the past month that my power #s sometimes show up in Final Surge, sometimes not. Today, I switched my Garmin watch (which receives the data and transmits it forward to Garmin Connect, thence to Final Surge) so that the Stryd is "Always" used for both speed and distance. So far (n=1) that worked.
Now, to a more fundamental issue...what the heck is going on with run power? My simple minded picture of what's inside the Stryd - what do we call it, a button? - is: three accelerometers measuring horizontal, vertical, and lateral change is position over time; a microprocessor to receive and make calculations based on that data that data; and BLT and ANT+ transmitters. So it is NOT measuring the force I am applying to the ground; it is measuring changes in three different planes of motion, all 90 deg to each other, and then making some calculations based on that data for things like: vertical oscillation, speed, and distance.
I do know that it is possible to run more efficiently, meaning use less "power" (as reported by Stryd) for the same speed on level ground. When I did my shoe test for the Vaporfly 4% in August, I found improvements in both form power and leg spring stiffness, as well as pace and total power, with the same HR and RPE on a standard 3 mile run. What I'm not smart enough to do yet is figure out how to make improvements in form *while running* based on data I can get from the Stryd. I can discover after a run if any specific area I worked on made a difference.
So far, I think power for running is about as much use to *me* as cadence on a bike...I record both for every ride/run, and occasionally look at them during a workout, but don't really make much effort to use the data.
As some of you might know, I have truely drunk the Andy Coggan kool-aid.
So, for training on my Garmin 935 I use lap power, lap time, total distance and lap pace (although I never look at it).
During each training block of 4-6 weeks, I do all-out tests at 5 secs, 1 min, 5 mins, and 20 mins. I use WKO4 to estimate my run FTP and use that to set my run training power levels.
BTW, I do the same testing protocol for the bike and use the WKO4 mFTP to set my bike training power.
@Al Truscott Vance's 'Run With Power' suggests you work on your efficiency by sitting on a set run pace, and try making changes to your form that lower your run power while leaving your pace unchanged. This assumes you are running on the flat with no wind.
That said, "The Secret of Running" suggests a 25 min 5 km runner potentially has 45 secs of efficiency improvement. IMO, a fair bit of potential efficiency can be obtained through adding some running at a power greater than your 5 min max power. Daniels repetition intervals do this. So I don't bother with Vance's suggestion.
I am pretty sure the STRYD uses 3 accelerometers measuring horizontal, vertical, and lateral acceleration over time (not quite what Al stated). Thanks to Isaac Newton, F=MA (as vectors) STYRD can resolve these forces to measure the forward power etc. Of course this assumes you have your correct weight entered into the Ap. From this, using Newton's laws of motion distance, power and energy expended can be calculated.
Happy to explain/discuss/elaborate further.
Thanks for starting this conversation @tim cronk and for all the input everyone else! I have been using Stryd since sometime this fall (September?). I am liking it more and more as I use it more. No races yet, just an all-out 5k solo.
Relevant question for people: What run power "threshold" do you all use in training peaks or WKO4, etc? @Tim Sullivan , @tim cronk , @Al Truscott and others? I know Final surge will do this, but I haven't set that up yet (procrastinating, not because I don't want to use it, just because I haven't prioritized it.). I used an all out 5k to calculate my critical power in stryd and run power zones. They seem to be pretty appropriate so far. Stryd power center gives me a range of "threshold" power. My guess was to use the middle of that threshold power zone in training peaks (hoping to get TSS calculations based on this).
PS. I asked this in forum instead of group-me in an effort to use forums more :) (since this will be in long term memory now for other users). I apologize if this was answered elsewhere. Thanks!
@Larry Peters on STRYD app and website settings there is a Critical Power Calculator which can calculate CP 4 different ways - 5k, 10k, 3laps/6laps , 3' and 9' , tests.... I recently completed the 3' and 9' test for a CP of 222 and a 5 mile race that I extrapolated that pace for a 10k and got 226.... I am using 222 in TP... I find it pretty accurate and like the TSS I am getting from that... Since you have a 5k I would suggest the 3' and 9' test for comparison and validation. FWIW the 3 ranges you are talking about I think is from the race calculator which is different from the CP calculator.
@tim cronk , ok, thanks a ton! I will try to do the 3' and 9' test sometime soon. I am using the "critical power" link in the Stryd app. I have not tried using the "Race Power Calculator" yet, which in my version of the stryd app is located just under the "critical power" tab in the "settings" menu.
I did just realize that Stryd uses the term "threshold" to describe the middle of the 5 power zones they assign (in the critical power tab). And critical power is the top of the "threshold" zone (Zone 3 in the stryd app). So I may change my TS "threshold" value to be equal to my critical power for now (the top, as opposed to the middle of Stryd's "threshold" range). But I definitely should do the 3' and 9' tests soon. Thanks again!
Steve Palladino has a FB page, The Palladino Power Project, where he discusses and posts a ton of info about using a Stryd power meter, and about running power metrics. A ton of good stuff...
https://www.facebook.com/groups/PalladinoPowerProject/permalink/2261946914057352/
Is there a preferred critical power test for Stryd? I was planning to do the 6/3 test. Is there a reason to go a different way?
@Janyne Kizer I don’t think it really matters. I chose the 3’ and 9’ , I liked the idea of fixed time vs. laps, also allows more choices for testing route selection.
Thanks @tim cronk for starting this thread and to the group for the great and wicked smart discussions. Sorry I procrastinated. Couple of personal measurements/info.
wt-128-130 lbs, 59 kg
ht- 5’4”
Flat stand alone marathon ave power (195-205), (3.3-3.5 Watts/kg)
pace- 7:35 min/mile.
Because of my injury, I have not ran hard or tested on the left side of the curve. However, I find that my long distance numbers are very close to @tim cronk ‘s numbers. For me it really doesn’t matter w the short distances or the stand alone marathon numbers. I’m really interested in finding out the accurate correlation of power between a brick run at medium distance (5-10 mi) and an IM marathon. Also, my “break down” number (beyond which I will blow up in a marathon as Tim puts it) is 210 watts (3.6 watts/kg).
If anyone knows that correlation, it would be so helpful. I recall that @Coach Patrick used Stryd for his brick runs and IM marathons. I wonder about his calculations/observations.
Thanks,
nam
@Nam Lam Thanks for asking this question. I went back and looked at my race rehearsals prior to last fall's IM AZ, and discovered that I did those runs @ 2.72 w/kg, and ended up doing most of IM AZ @ 2.5 w/kg, or 92% of my RR power. All the courses were similar in terrain and weather/temp. I would suggest that an *ideally* trained and executed race would end up quite near 100% of one's race rehearsal power, and anything over 90% I would term "successful".
Of some interest, the week before IM AZ, I did an half Iron in Miami attempting to run @ my IM pace. I was not looking at any data while running, just going by RPE, which is pretty much what I do for almost all training runs, race rehearsals, and races. The temp was low 80s, compared to mid 60s in Tempe. My w/kg for those 13 miles were 2.55.
Back in 2007 or so, EN athletes pooled their data on the bike in IMs to obtain a curve which correlated bike TSS & IF to success or failure on the run. It may be time for a similar project using run power data?
Thanks @Al Truscott . That’s a great idea. This is especially helpful for us IMAZ folks who may benefit from the data because we race later in the season. I don’t mind providing my own data. I’m also racing IMSR so we’ll have some of that data early as well.
I've also had the experience that my Stryd-estimated half marathon power based on Critical Power was too low, by about 10W. I think part is I just don't push as hard in tests as I can go in an A race.
Here is a table from Stryd that I found helpful to scale power from one race distance to another (note this is scaled so 100 is 10k power, NOT critical power):
5k 103.8
10k 100
Half Marathon 94.6
Marathon 89.9
They are just like the bike PDC charts
-FTP Contribution with TTE - Run
-Best Times for Informal Testing
FTP Contribution with TTE
Just like the bike version. This chart shows how much power is generated
aerobically v. anaerobically at a given time interval for max power
efforts. It shows when you shift from anaerobic to aerobic energy
production for a given time and power.
Best Times for Informal Testing
Gives recommendations for maximal power test durations, based on how your
current efforts (loaded data) matches the WKO4 Power Duration Curve model.
It potentially is a good estimation of your potential max power for each
duration, and shows you potential areas of improvement.
I don't have enough maximal data loaded to get a good model. I'm interested
to hear your thoughts for those that have some good max test data.
On Thu, Jan 31, 2019 at 7:24 PM Mike Westover <
teamenforums+d25434-s6029573@gmail.com> wrote:
> [image: Endurance Nation Community]
>
> ------------------------------
> Mike Westover commented on STRYD Critical Power Estimating/Racing Estimate
> Data
>
> I've also had the experience that my Stryd-estimated half marathon power
> based on Critical Power was too low, by about 10W. I think part is I just
> don't push as hard in tests as I can go in an A race.
>
> Here is a table from Stryd that I found helpful to scale power from one
> race distance to another (note this is scaled so 100 is 10k power, NOT
> critical power):
>
> 5k 103.8
>
> 10k 100
>
> Half Marathon 94.6
>
> Marathon 89.9
>
> --
> Reply to this email directly or follow the link below to check it out:
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@Mike Westover I found those percentages of 10k to be pretty close.... Just like bike power they should be slightly different for each individual but great rule's of thumb.
@matt limbert - I have those new charts, just like my bike, it shows my weakness in the 1-3' area. I am using Critical Run Power and Pace Chart to follow my best 3' and 9' efforts and calculate my CP. Between STRYD CP calculator and WKO4 CP calculations using 3' and 9' , and then correlated to a 5 mile run which I extrapolated pace to a 10k so should be very close I am getting a CP range of 222-226 which is pretty good IMO considering more than one way of going about the math. Reference max efforts with STRYD- since its not a strain gauge measuring force I think these very short hard intervals of sub 1' sprints would be very hard to get, specially considering the risk of injury that maybe involved. I dont see much difference between a 1' all out effort and a 3' effort as far as watts goes, maybe 10?, those that are playing with more watts should see a bigger differential. Below is an updated list of my max power at different time frames. While I wish I could get some more max power numbers sub 3' to help with the power curve, I'm not sure I wanna risk the injury or if the data would be good enough . As it stands I am happy and believe the power curve I have produced with STRYD data so far and more importantly the TSS relative in each run. The range is tight and the curve drops slowly.
3'- 243w- test
9'- 229w- test
34'- 227w - 5 mile road race
65'- 198w - 8 mile trail race(only one out of line vs. time but fatigue and trail conditions played a part)
89'- 221w - HM road race
5hr -163w - 163 50k trail race
Even though I've had my stryd for over a year now, I just did my first run this weekend with it. A whole 70mins on the treadmill!
Cannot wait to dig into the weeds a little more!
Reviving this thread -- I have had the Stryd for about 2 years but have not really used the numbers for training.
I did a 5k test yesterday, ran a 20:43 at 264 watts. Styd calculator estimates a critical power of 262 but a threshold range of 236-262. I haven't done the 3 min, 9 min test in awhile. Is there a consensus on what number to use to set run power zone?
@Mark Roberts Go with 262 , that is your CP. Validate with the 3' and 9' test when you can. If you have WKO4 there is a chart that shows your top three 3'and 9' efforts and the CP that results.
So, any suggestions about whether to call yourself a “speed demon,” “balanced runner,” or “aerobic monster,” when using stryd power center to predict target power for a race (for me: 336, 344, or 353 w)? I imagine all the cycling triathletes do tends to move us closer to the aerobic “monster” side V’s. The same person who would only run...
I saw the 94.6% of CP for a half marathon someone suggested above. That would be 344 W for me (aka, balanced runner accordingly to stryd race power calculator). Thanks!
I’m predicting for a “half marathon” race using 5k test from 2/4/19 (actually racing 25k, so plan to dial power down a little because of the extra ~2.5 miles).
i will take RPE into account & have many years of running based on RPE, but in the last year, I haven’t done much running in the HM intensity zone. I am now wondering why I didn’t do a race rehearsal recently? 🙄🤷🏻♂️.
the EN HM plan has an 8 mile run on Saturday with 4 easy & 4 at race pace. So I’ll probably do that & look at HR, power, pace & see how that feels.
i also did this race 2 years ago & really want to beat my pace from that (7:08 pace). Would love to break 7 min pace, which would be ~1.8% improvement, but that may be shooting for the moon. So I may just use 7:08 pace as a whip & just make sure the corresponding power number is within the range given by power center.
the race in question is pretty flat with a few rollers toward the end.
sorry, I rambled a bit there, but any insights are greatly appreciated! Thanks!