Training Stress Score (TSS): Your Roadmap to Smarter Training
Ever found yourself wondering, “Am I training hard enough, or maybe too hard?” It’s a question many time-crunched endurance athletes ask, especially when trying to juggle work, family, and big race goals. That’s where the Training Stress Score (TSS) comes in—a metric used by popular platforms like TrainingPeaks, TrainerRoad, and more. TSS helps quantify the load each workout imposes on your body so you can balance training, recovery, and real life without constantly second-guessing. Dr. Andy Coggan and Hunter Allen pioneered TSS with the original seed concept being developed by Dr. Eric Bannister’s heart rate-based training impulse (TRIMPS).
Or if you want to take the mental energy out of training and recovery book a free coaching consultation below – Get 2 Weeks of free coaching with no sign up required to see if it is a fit for you.
What Is TSS and How Is It Calculated?
TSS is a single number that represents how tough a workout was, based on intensity and duration. If you’ve ever wondered how it’s calculated, TrainingPeaks has a detailed formula and description, but in essence, it looks something like this:
(Note: The precise formula can vary based on whether you’re measuring by power, heart rate, or pace, and the platform you are using but the concept remains the same.)
- Higher TSS means a longer or more intense session.
- Lower TSS reflects a shorter or easier session.
Think of TSS this way:
- A completely all-out, 60-minute effort (at 100% intensity) is worth 100 TSS.
- Since most training sessions aren’t done at full-throttle, you’ll typically earn fewer than 100 TSS in an hour.
- You can accumulate more than 100 TSS overall if the workout goes beyond an hour, but you can’t exceed 100 TSS per hour.
- To visualize it using an RPE (Rate of Perceived Exertion) scale from 1 to 10—where 10 is the hardest—an effort of 5 for two continuous hours would equal 50 TSS per hour, or 100 TSS total.
- Whether you’re a seasoned pro aiming for the Tour de France or a first-time triathlete, this principle remains the same.
Regardless of the exact formula, the fundamental idea is that TSS encapsulates how much stress you placed on your body—in one easy-to-track number.
Why TSS Matters
- Balancing Training and Life: When every minute counts, you need to ensure those minutes are purposeful. TSS confirms whether a short session can still be high quality or if a longer, moderate session is the right call.
- Preventing Overtraining: Consistently high TSS can be a recipe for burnout or injury if not balanced by recovery.
- Tracking Progress Over Time: Watching TSS trends gives you a long-term view of whether your fitness is improving, plateauing, or regressing.
The Performance Management Chart (PMC)
In TrainingPeaks (and similar tools), TSS data feeds into the Performance Management Chart, which tracks three main metrics:
Chronic Training Load (CTL) = “Fitness”
- Average daily TSS over a longer period (about six weeks).
- Rising CTL suggests increased fitness—if your body can handle it.
Acute Training Load (ATL) = “Fatigue”
- A rolling average of TSS over a short window (about a week).
- If ATL climbs too fast, expect some heavy legs and mental fatigue.
Training Stress Balance (TSB) = “Form”
- Essentially CTL minus ATL.
- A negative TSB means you’re carrying fatigue; a positive TSB indicates freshness.
By keeping tabs on these metrics, you can schedule tougher sessions when you’re fresh and slip in recovery days before fatigue derails your progress.
How TSS and the PMC Guide Your Training
- Plan Smarter, Not Harder: If your workload is piling up and TSB is consistently deep in the negative, you might need a break. It’s the difference between productive training and punishing your body.
- Manage Life’s Curveballs: Missed a workout because of a late meeting or a kid’s soccer game? The PMC shows how to tweak the rest of your week to stay on track.
- Nail Your Peak: Most of us want to be at our best on race day, not three weeks before. By watching the trends, you can time your taper so you arrive fresh—yet fit—at the start line.
Reducing the Mental Load
Instead of agonizing over whether you did enough or maybe overdid it, let TSS guide you. Log your workouts, watch the Performance Management Chart, and make adjustments based on your metrics. You’ll gain confidence knowing you have a data-driven plan rather than relying on guesswork.
Take the Guesswork Out of Your Training
Struggling to figure out the right blend of effort and recovery? That’s where personalized coaching comes in. A coach can monitor your TSS, analyze the trends, and make strategic tweaks to your plan so you can focus on executing workouts—rather than obsessing over the data.
Book a free consultation to get 2 Weeks of Free Coaching with no sign up to see if it is a fit for you.
Ready to eliminate the stress of analyzing TSS and the Performance Management Chart yourself? Reach out about coaching today. I’ll handle the numbers so you can get the most out of every workout—and still have time for the rest of your busy life.