STRYD Race Calculator 🥇Event Planner

Key Performance Features Free For STRYD Users

STRYD’s continued investment in their training platform is paying off. There are already some great features on there like Critical Power Analyses but one of the missing things was race day planning. That omission is now addressed as STRYD adds a planner for your SPECIFIC EVENT-DAY conditions as well as a Race Calculator to enable you to model various outcomes.

Bear this in mind

  1. The broad assumption is that constant power is optimal for your race.
  2. The relationship between pace and power varies based on several factors such as SLOPE, thus to target a race time you need to understand the specific relationship between them all on race day
  3. Today’s maximum achievable power for you for any given duration can change based on environmental conditions such as altitude and temperature.
  4. STRYD’s race calculator works on your demonstrated power capability rather than the results of their CP model used elsewhere in Powercenter (I’m assuming the two are closely linked)

Cyclists who train with power will be familiar with Best Bike Split (BBS), MyWindSock and many other sites where similar kinds of modelling are available. Typically the likes of BBS will specify slightly higher power for uphill sections and slightly lower power for downhill (+/-5%), which seems different to STRYD approach from what I can see.

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Getting Started

The new features all work now on the STRYD app and online in Powercenter. As long as you have enough runs with STRYD for it to calculate your CP, all should be good. Ideally, you will also know your exact race date and location.


Choosing a Course

STRYD has a public library of verified marathon courses complete with the elevation profile. Not doing a marathon? No problems, you can upload a FIT file of your intended race-day course. The verified courses already have the ground conditions hard-coded in and for other courses, you will have to estimate these manually.




Modelling Race Day

STRYD PowerCenter lets you play with the race-day conditions, namely elevation, temperature and humidity, which will impact on your target power. Interestingly STRYD seems to account for the differential between your typical training conditions and the race day conditions, rather than just looking the race day conditions that other platforms only seem to consider.

It’s interesting to play with these inputs but, in normal, conditions they make little difference to the target power and were of the magnitude of +/-5w for some of the scenarios I tried. However, clearly, we all occasionally encounter adverse conditions such as a particularly hot, humid day – you can try entering 30Celcius and 95% humidity and you will see a more dramatic change to the target power of up to 8% or 10% depending on your historic training conditions.

Wind and Surface condition do not affect your target power but they will affect your race day time. Neither seems to be modelled at present but the video from STRYD, below, states that they are working on that.

The fairly long video discusses the kinds of modelling you can do in a little more detail.


Take Out: These kinds of tools have been available elsewhere for some time and it’s great they are now available for RUNNING WITH POWER.

Race Day Pace

In this example, over the Tokyo Marathon course, you can see that the (circled) course profile is downhill at the start. The power profile is CONSTANT throughout the race, however, for the downhill section, you can see the required pace increases.

STRYD seem to discuss PACE infrequently, perhaps deliberately they want to focus our minds on their power metric. However, if the race-day effort could be produced by STRYD as a FIT file then Garmin devices would be able to ‘race the FIT file’ for those of us who might also want to have a fallback on PACE as a sanity check against any power levels shown on our watch.

Of course, Garmin also has the PacePro feature for those of you who are interested in modelling your race splits by pace over undulating courses.

Take Out: A FIT file output of the race day plan might be of some additional benefit.

Progress Toward Race Day

STRYD users and bike power users will already be aware of their CP curve. A CP curve based on either actual efforts or modelled efforts will show your maximal power abilities for any time duration.

STRYD introduced their CP curve a while back and it auto-calculates your CP based on new results and adjusts itself as the effects of old results wear off. Part of this feature is that you are automatically notified when your CP changes and this also automatically updates your power zones. However, this notification will also mean that your race day forecast has changed too and this will be the time to pop over to the event planner/Race Calculator to see what impact this might have for you on race day.

Take Out: STRYD probably need to have a more formal process of calendarising an event. Once an event is calendarised the changed CP notification would also notify you with any updates to your race day power/time.

STRYD Race Calculator Overview

Here’s an overview of the screen on PowerCenter by STRYD

Source: STRYD

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13 thoughts on “STRYD Race Calculator 🥇Event Planner

  1. looks interesting but i much prefer mile pace splits and you can get thoese easily enough with online tools that also take into account all the factors you talk about. I don’t need to spend an extra 200 bucks for that when its free

    1. It be interested to know what free tools you’re referring too. Free is great, but mile pace splits are going to be less accurate than your instantaneous power – unless your hills are always > 1mile 🙂

      1. thanks Will, you seem to be my new tech support agent today ;-). i think there is more granularity in PacePro but your point stands

    2. You could run the same by pace if you know your perfect pace, the gradient of every uphill and downhill and the pace differential you can maintain up and down without affecting your pace on the flats, plus the effects of weather. Pretty difficult for most on a long hilly course.

  2. what about wind? stryd used to say its effect was minimal with there last product then they introduced the latest stryd which does take it into account. now they dont include wind in this model.
    which is it?
    how can you model wind in an urban marathon where the wind direction will be funnelled by buildings

    1. Wind isn’t in the Race Power Calculator but it is in the Stryd pod. So you still run at target race power, but your pace will vary depending on the wind that day.

      1. indeed so, your race total average power shoudl be achievable but the time achieved might be less with an unfavourable wind.

  3. Thanks 5k love your site. I used a calculator that you linked to ages ago which is amazing and includes all these factors and references Daniels’ tables. not sure what extra Stryd add here and i looked at their calculator yesterday out of curiosity ( I have stryd)

    My question is that Stryd seems to use different temperature factor to Daniels. So who is right?

    1. extra Stryd add here” It’s all automated and after the initial purchase of Stryd, it’s free 🙂

    2. ok just checked that. yes the electric blues/daniels seems to use 16 celcius as the point above which temperature has a negative effect. but stryd seem to use a higher temp. I don’t know which is correct, there will be some pesky science somewhere to support either camp no doubt

  4. I think this is a great update. Whilst I’ve seen spreadsheets that offer some similar functionality they are not so user friendly. Stryd automatically harvests your training data to give a prediction of your up coming race performance with minimum technical effort – how great is that!

    1. true. many of the other tools seem to base their output on ONE input ie a race like efforts at a usually shorter distance. i don’t know how STRYD works but I expect it would be like the other published CP models and so would base any CP prediction on more than one duration point. (possibly more accurate for less trained runners). they also state that they use ACTUAL efforts as a race-day predictor, again this might help less trained runners who typically can’t produce the longer-duration race efforts that some of the models predict.

      having said that, most of the online calculators are simple to use (perhaps the spreadsheet referenced ealier is an exception 😉 )

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