Training effectively is not just about putting in the hours—it’s about balancing intensity, recovery, and progression. For endurance athletes like cyclists, runners, and triathletes, Training Stress Score (TSS) is a valuable metric that helps quantify how much strain a workout places on the body.
Our TSS calculator simplifies the process of tracking training stress, allowing athletes to fine-tune their workouts for optimal performance and recovery. In this article, we’ll cover what TSS is, how it’s calculated, why it matters, and how our TSS calculator can help you improve your training.
What is Training Stress Score (TSS)?
Training Stress Score (TSS) is a numerical value that quantifies the intensity and duration of a workout. Developed by Dr. Andrew Coggan, TSS is widely used in endurance sports to measure overall training load.
TSS helps answer important questions:
✅ Did I train too hard or too easy today?
✅ How much recovery time do I need?
✅ Am I progressing toward my fitness goals?
By tracking TSS over time, athletes can prevent overtraining, improve endurance, and enhance performance.
Why is TSS Important?
1. Prevents Overtraining & Undertraining
Without tracking training stress, athletes risk training too much or too little. Overtraining leads to fatigue, injury, and burnout, while undertraining results in stagnation and lack of progress. TSS ensures that each session contributes effectively to overall fitness.
2. Improves Training Efficiency
Rather than guessing how hard a workout was, TSS provides quantifiable data that allows athletes to adjust intensity and duration for maximum gains.
3. Helps Plan Recovery & Workouts
TSS helps determine when to push harder and when to rest, making it a key tool for periodization and structured training.
4. Tracks Long-Term Progress
By analyzing weekly and monthly TSS trends, athletes can track fitness improvements and adjust their training plans accordingly.
How is TSS Calculated?
TSS is calculated using a scientific formula that considers the workout duration and intensity relative to an athlete’s Functional Threshold Power (FTP).
TSS Formula:
TSS=(Workout Duration (in seconds)×Normalized Power×Intensity FactorFunctionalThresholdPower×3600)×100TSS = \left( \frac{{\text{Workout Duration (in seconds)} \times \text{Normalized Power} \times \text{Intensity Factor}}}{{Functional Threshold Power \times 3600}} \right) \times 100TSS=(FunctionalThresholdPower×3600Workout Duration (in seconds)×Normalized Power×Intensity Factor)×100
Where:
- Workout Duration = Total time spent training (in seconds).
- Normalized Power (NP) = A refined measure of effort output.
- Intensity Factor (IF) = A ratio of the workout intensity relative to FTP.
- Functional Threshold Power (FTP) = The highest power output an athlete can sustain for one hour.
For runners and triathletes, TSS can be adapted using heart rate or pace-based equivalents instead of power-based metrics.
Understanding Your TSS Scores
To make the most of TSS tracking, it’s essential to interpret your scores correctly:
| TSS Score | Training Effect | Recovery Time Needed |
| 0 – 50 | Light workout, minimal fatigue. | None or very little. |
| 50 – 100 | Moderate effort, manageable stress. | 12-24 hours. |
| 100 – 150 | Hard workout, requires recovery. | 24-48 hours. |
| 150 – 200 | Very intense, may cause fatigue. | 48-72 hours. |
| 200+ | Extreme effort, high risk of overtraining. | 72+ hours. |
Maintaining consistent TSS levels and avoiding excessive spikes helps improve performance safely and effectively.
Best Practices for Using a TSS Calculator
✅ 1. Track Your Weekly TSS
Maintain consistent weekly TSS levels to avoid burnout and stagnation.
✅ 2. Balance Hard & Easy Sessions
Ensure high-TSS workouts are followed by lower-TSS recovery days.
✅ 3. Use Power Meters & Heart Rate Monitors
For accurate TSS calculation, use power-based or heart rate-based data.
✅ 4. Adjust Based on Performance Trends
Monitor TSS trends over time and modify training intensity accordingly.
Conclusion
Tracking Training Stress Score (TSS) is essential for athletes who want to optimize performance, prevent overtraining, and structure their training effectively. Using our TSS calculator, you can:
✅ Monitor training load with precision.
✅ Optimize workouts for peak performance.
✅ Prevent fatigue and overtraining.
✅ Track long-term progress effectively.