• Get Started
    • Get Started on Zwift
    • Zwift Course Maps
    • How to Race on Zwift (Setup, Strategy, and More)
    • Links Every Zwifter Must Have
    • More “Get Started” Posts
  • Tips & Tricks
    • Kit Unlock Codes
    • Training & Nutrition
    • Racing
    • Zwift Hacks
  • Reference
    • How Zwift Works
    • Course Calendar
    • RoboPacer Calendar
    • Smart Trainer Index
      • Top Wheel-On Trainers
      • Top Direct-Drive <$900
      • Top Direct-Drive >$900
      • Exhaustive Trainer List
    • Achievements & Unlocks
    • Frames & Wheels
    • Routes & Maps
      • Master List of Routes
      • Master List of KOMs
      • Master List of Sprints
      • Downloadable Watopia Map
      • Rebel Routes
    • Speed Tests
  • News
    • Events
    • Game Updates
  • Shop
Search
Logo
Logo
  • Get Started
    • Get Started on Zwift
    • Zwift Course Maps
    • How to Race on Zwift (Setup, Strategy, and More)
    • Links Every Zwifter Must Have
    • More “Get Started” Posts
  • Tips & Tricks
    • Kit Unlock Codes
    • Training & Nutrition
    • Racing
    • Zwift Hacks
  • Reference
    • How Zwift Works
    • Course Calendar
    • RoboPacer Calendar
    • Smart Trainer Index
      • Top Wheel-On Trainers
      • Top Direct-Drive <$900
      • Top Direct-Drive >$900
      • Exhaustive Trainer List
    • Achievements & Unlocks
    • Frames & Wheels
    • Routes & Maps
      • Master List of Routes
      • Master List of KOMs
      • Master List of Sprints
      • Downloadable Watopia Map
      • Rebel Routes
    • Speed Tests
  • News
    • Events
    • Game Updates
  • Shop
More
    Sign in
    Welcome! Log into your account
    Forgot your password? Get help
    Privacy Policy
    Password recovery
    Recover your password
    A password will be e-mailed to you.
    Tips & TricksTraining & Nutrition

    All about TSS (Stress Points) in Zwift

    Eric Schlange
    By Eric Schlange
    November 14, 2018
    10

    When you begin a workout in Zwift you may notice a “stress points” rating. And when you finish any Zwift ride you’ll see a guy at the top-right telling you how hard you worked.

    Where do those numbers come from, and how are they useful?

    Zwift’s “stress points” are really just TSS–the same number you see when you end a ride. Training Stress Score was developed by TrainingPeaks as a key workout metric. It combines both time and intensity into one metric which indicates how much stress your workout is putting on your body.

    Let’s dig into TSS a bit more to learn how it is calculated and used.

    First, a Big Nod to the Creators

    The TSS (Training Stress Score) and IF (Intensity Factor) metrics were created by Dr. Andy Coggan and Hunter Allen. Coggan also created NP (Normalized Power). TSS, IF and NP would eventually be purchased by TrainingPeaks and trademarked.

    Coggan, Allen, and TrainingPeak’s Joe Friel have done amazing work developing metrics and tools that help us train smart. They deserve kudos for the many ways they have helped cyclists take their training to the next level.

    (Side note: if you’re ever looking for good books on training with power, pick up Coggan and Allen’s Training and Racing with a Power Meter and/or Friel’s The Cyclist’s Training Bible. Both incredible resources for anyone interested in getting faster on the bike!)

    Power Required

    It’s worth noting that calculating TSS requires power numbers. Twenty years ago these numbers weren’t accessible to most cyclists, but nowadays with affordable power meters and smart trainers many cyclists have power data for every ride. It’s a great time to be alive and training!

    Connect to TrainingPeaks

    If you haven’t yet done so, I recommend heading to TrainingPeaks.com (or downloading their app) and creating a free account. Upload all your ride data to this account and you will have TSS and other metrics stored for every ride.

    • Link your Zwift account to TrainingPeaks by logging into Zwift.com and clicking “Connect” under Profile>Connections.
    • Outdoors I use (and love!) my Wahoo Elemnt bike computer which uploads my rides to TrainingPeaks as well as Strava. If you have a power meter for outdoor rides, set up your bike’s computer to upload to TrainingPeaks. This way you’ll have all your rides analyzed by TrainingPeaks.

    The Formula

    Here is the formula for calculating TSS:

    TSS = [(sec x NP x IF)/(FTP x 3600)] x 100

    Where “sec” is how many seconds your workout lasted, NP is normalized power, IF is intensity factor, and FTP is your functional threshold power. Most of those numbers will be familiar to you, but “Intensity Factor” may be new. It’s simple though: IF is the ratio of Normalized Power to your FTP for any given workout. So if an athlete with an FTP of 300 watts completed a workout averaging 200 NP their IF would be .67.

    TSS calculation examples (assuming FTP of 250 watts):

    • Ride at FTP for 1 hour: [(3600 x 250 x 1)/(250 x 3600)] x 100, or 100.
    • Ride at 75% FTP for three hours: [(10800 x 187.5 x .75)/(250 x 3600)] x 100, or 169.
    • Ride at 50% FTP for five hours: [(18000 x 125 x .5)/(250 x 3600)] x 100, or 125.

    Once you understand the formula you will see that you can earn more than 100 TSS within a single workout, but only if the workout is longer than an hour.

    It’s All Relative

    Since TSS is based on your personal FTP, a TSS of 100 is relatively the “same” for a professional athlete as it is for a beginner. This is the genius of the TSS metric.

    As an example, if a pro cyclist “Pro Joe” went out and did a 1-hour ride that resulted in a TSS of 100, this would be a max effort for him. In simplified terms, if Joe’s FTP was 350 watts, this means he would have held 350 watts for the full hour. Animal!

    Then a mere mortal, let’s call him “Cycling Bob”, comes along with an FTP of 225. Bob goes out and hammers for an hour, holding 225 watts the whole time. His TSS will be 100 as well.

    Even though Joe and Bob moved at very different speeds during their rides, they both gave it their all for that hour. Their relative effort levels were the same, which is why their TSS is the same.

    What’s the Use?

    This is a massive topic, and one in which I’m no expert. What I can say with confidence is it’s the best metric I’ve found for how hard a day’s effort really was, and that helps inform my recovery needs that follow.

    Many coaches and athletes also use cumulative TSS (per week or per month) to figure out the volume of training which will leads to improvements but avoid overtraining. Athletes might ramp up their TSS leading into a big event, building each week from (for example) 600 TSS to 700 then 800.

    There is much more to this topic, but we’ll leave it here for today. I’m curious: do you pay attention to TSS? How have you found it useful in your training? Comment below!

    Related Posts

    Facebook
    Twitter
    Pinterest
    ReddIt
      Eric Schlange
      Eric Schlangehttp://www.zwiftinsider.com
      Eric runs Zwift Insider in his spare time when he isn't on the bike or managing various business interests. He lives in Northern California with his beautiful wife, two kids and dog. Follow on Strava

      10 COMMENTS

      Subscribe
      Connect with
      Notify of
      guest

      Connect with
      guest

      10 Comments
      Oldest
      Newest Most Voted
      Inline Feedbacks
      View all comments
      Perry Alan McFall
      Perry Alan McFall
      3 years ago

      TSS only show up for me on workouts – not group rides or races. Where the score would appear I have the climbing challenge and and not able to find a way to change this.

      0
      Reply
      Eric Schlange
      Author
      Top Member
      Eric Schlange(@eschlange)
      3 years ago
      Reply to  Perry Alan McFall

      TSS shows as the top-right of your ride summary screen when you complete the ride.

      0
      Reply
      Tanya Clark
      Tanya Clark
      2 years ago

      I have just started with a coach and they have asked me to do a Zwift ride for 1hr30min with a T75, how do I manage my TScore while training so that I get that result

      0
      Reply
      Spixy
      Spixy
      2 years ago

      I can see my TSS at end of ride, but don’t know how to access that information once that screen goes.

      9
      Reply
      Tom Scanlon
      Tom Scanlon
      2 years ago

      Any way to get Zwift rides to show TSS and IF in Garmin Connect. They show up for TrainerRoad rides.

      0
      Reply
      Cr.Rand
      Cr.Rand
      2 years ago

      Had previously only been looking at wattage zones for recovery rides but now using the TSS more now to help keep myself in-check for recoveries and to curb enthusiasm for doing hard/long rides every single day.

      Wish the TSS was embedded and displayed permanently in our Zwift Activity feed but make it’s a licensing issue?

      1
      Reply
      Jerome Lawther
      Jerome Lawther
      2 years ago
      Reply to  Cr.Rand

      I wish it showed up in the activity feed too.

      0
      Reply
      bikingyom
      bikingyom
      2 years ago

      The formula could be simplified to this, am I right?
      TSS = 100 x hours x IF^2
      (because sec/3600 = hours, and NP/FTP = IF)
      But if I use this formula on each interval in any zwift workout and make the total, it never ends up on the zwift stress points. Do you have an explanation?

      1
      Reply
      Kyle
      Kyle(@kylebredesky)
      1 year ago

      I’m late to the party here, but maybe will snag a reply. I’m just connecting this… Am I right in thinking that the “stress points” when choosing a workout are an estimate of what your TSS will be for that session?

      0
      Reply
      John
      John(@profjohnbowers)
      9 minutes ago

      You could get a TSS over 100 in an hour if you are riding intervals and staying near threshold the rest of the time. In this case your IF will be larger than 1. Also, the much simpler formula for TSS is (IF)^2 X time in hours X 100 which is the same as the formula stated in this article, but more digestible. As a mathematician, I gotta say all the NP, IF, and TSS stuff feels a little bit “how to lie with math” to me. What biological reason is there for squaring IF? Why not cube it? What… Read more »

      0
      Reply
      wpdiscuz   wpDiscuz

      Free Zwift Trial

      Create Account

      Newest Featured Posts

      Zwift Insider Worlds Experience Races Announced

      Events

      Zwift Racing League Week 5 Guide: France’s R.G.V. (TTT)

      Racing

      Zwift Course Calendar – Current Guest World Schedule

      Reference

      Support This Site

      Contribute a post, shop through us, make a donation, advertise on this site. See how you can support Zwift Insider!

      This community-driven site is maintained by Eric Schlange and a team of Zwift enthusiasts. Zwift Insider is independent of Zwift corporate (www.zwift.com), although Zwift does provide funding to help defray site costs.

      This site contains affiliate links to Amazon, Wahoo, and other brands. Zwift Insider makes a small commission on purchases made from these links, so please shop through them to support our efforts.

      Terms of Use/DMCA Copyright Policy

      Privacy Policy

      [email protected]

      Latest articles

      Zwift Insider Worlds Experience Races Announced

      Top 5 Zwift Videos: Platform Comparisons, Breakaways, and Pace Partners

      “Loch Loop” Route Details

      Popular Categories

      • Racing985
      • News738
      • Training & Nutrition582
      • Events508
      • Interviews440
      • Routes & Maps311
      10
      0
      Would love your thoughts, please comment.x
      ()
      x
      | Reply
      Comment Author Info
      :wpds_smile::wpds_grin::wpds_wink::wpds_mrgreen::wpds_neutral::wpds_twisted::wpds_arrow::wpds_shock::wpds_unamused::wpds_cool::wpds_evil::wpds_oops::wpds_razz::wpds_roll::wpds_cry::wpds_eek::wpds_lol::wpds_mad::wpds_sad::wpds_exclamation::wpds_question::wpds_idea::wpds_hmm::wpds_beg::wpds_whew::wpds_chuckle::wpds_silly::wpds_envy::wpds_shutmouth:
      ‹ Back to Categories
      You are going to send email to

      Move Comment


    • Related Posts