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Stryd Running Stress Score

Mike WestoverMike Westover
in General Training Discussions
Stryd has introduced a new metric, the Running Stress Score. The formula is similar to TSS but with a bigger coefficient, so you will accumulate more RSS/hour than TSS/hour for runs above threshold, and fewer below threshold. Supposedly this better tracks the stress of increasing running intensity. The blog post with details on RSS is here: http://blog.stryd.com/2017/01/28/running-stress-score/ 

The formula is RSS = 100 x training duration x (Power/CP)^K

What is not mentioned in the post is the value they are using for K. I tried to reverse-engineer it from the charts there, but I'm not getting a consistent number. 

Comments

  • Shaughn SimmonsShaughn Simmons
    Thank you for posting this!  I am going to keep watching how this continues to evolve because I truly believe they are on the right track with more and more refinements coming and future alignments with the TSS side.....

    SS
  • Peter NoyesPeter Noyes
    I just did my first run with RSS. It was a long run with 10' Run / 5' Walk for 2:00. Stryd gave me an RSS of 118. TrainingPeaks gave me a TSS of 122.4. I would have figured that RSS should be higher based on the description of the announcement? Maybe its the walking breaks?
  • Mike WestoverMike Westover
    @Peter Noyes since your long run power is probably below threshold, I'd expect RSS to be lower than TSS. The formula is set up so that above-threshold-power runs get many more points than they would have with TSS (due to the impact of high-intensity runs on the body). If you're running right at threshold / critical power then the numbers should be the same. 
  • Tom GlynnTom Glynn
    Not sure what to think!  RSS 72, TSS 112 for a 13.5-mile treadmill run today.  TP has 6:12 threshold pace.  
    Stryd critical pace 6:12, CP 323
  • Robert SaboRobert Sabo
    @Tom Glynn what was your average pace and did you do any time at or below TP? Also curious as to what is your TRP?
  • Tom GlynnTom Glynn
    For my long runs, I'm starting to ramp for IM Texas. I use the same methodology for most long runs, including this one.  8-10 minute warm up ramping from walk to 8:00 min/mile on the most accurate treadmill in the gym.  (Treadmill distance 13.5 miles - Stryd foot pod 13.48 calibrated on a track) then hold the same 8:00 min/mile to the end.
  • Coach PatrickCoach Patrick
    @Tom Glynn any chance that the fact the treadmill is working for you vs you running has an impact on the total power generated? I know for me my HR is 10 beats lower on a treadmill at the same pace, so intuitively it makes sense to me that a treadmill run of 13.5 would be much lower than an outdoor run of 13.5.....but that wasn't the case in TP.com...it showed the same TSS. But with Stryd...maybe that's more accurate? 
  • Tom GlynnTom Glynn
    @Coach Patrick  I was thinking the same thing. My CP test was done on a really nice track, so sort of cushioned, but still way harder than a treadmill.  I'm running a 5K this weekend to set zones, so I'll see how the pace/power fall out.
  • Coach PatrickCoach Patrick
    Tom, perfect. Thanks for the heads up and good luck this weekend!!!  :sweat_smile:
  • Mike WestoverMike Westover
    @Tom Glynn what running threshold power do you have set in TP? That TSS looks high to me if you were at ~0.74 IF (240/323). 

    If you don't have a separate running threshold power set, TP will use your bike FTP, which can give you TSS numbers that are too high. You can set the run power in Settings --> Zones --> Power --> Run Power.
  • Tom GlynnTom Glynn
    @Mike Westover Thanks for the tip!  I had no idea that TP had a run power zone.  I just updated it.  My run power is 323, bike power 300 in TP.

    A lower bike power would give me a higher TSS score. I'll take a look at the run formula in Stryd too to see if I can make more sense of it.  I should get off the treadmill too to get a better comparison.

    Thanks!
  • Kyle KolquistKyle Kolquist
    I just got mine in the mail. Any tricks/shortcuts to getting this set up? Is everyone still using power in bike mode?
  • Peter NoyesPeter Noyes
    @Kyle Kolquist - If you have a Garmin that supports ConnectIQ you can now download a data field that records the power so you don't have to use bike mode. When you sync with Garmin Connect the data will go to Stryd PowerCenter where you should be able to see your power.
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