CoachingAnswer

WHAT IS TRAINING STRESS SCORE (TSS)?

By Anthony WalshRoadman CyclingUpdated 10 July 2026

ANSWER

Training Stress Score (TSS) is a single number that quantifies the physiological cost of a ride based on its duration and intensity relative to your functional threshold power (FTP). Developed by Dr Andrew Coggan and Hunter Allen, TSS is calculated as (duration in seconds x normalised power x intensity factor) / (FTP x 3,600) x 100. A one-hour ride at FTP equals exactly 100 TSS. The metric allows riders to compare the training load of different sessions, manage accumulated fatigue, and plan recovery.

KEY TAKEAWAYS

TSS quantifies ride load: one hour at FTP equals exactly 100 TSS.
Low-intensity long rides and short high-intensity sessions can produce similar TSS values.
Weekly TSS of 300-500 is typical for amateur cyclists training 6-10 hours per week.
TSS tracks acute and chronic training load, enabling fatigue management through CTL, ATL, and TSB.

WHO THIS IS FOR

IS THIS YOU?

The power meter user who ignores TSS

You have a power meter and see TSS numbers on your head unit but do not know what they mean or how to use them.

The self-coached rider planning a training block

You want to structure weekly training load and manage fatigue without guessing.

The data-curious cyclist

You have heard coaches talk about CTL, ATL, and form, and want to understand the maths behind it.

THE ROADMAN VIEW

TSS is the simplest way to answer the question every cyclist should be asking after a ride: how much did that cost me? Not in calories — in recoverable training stress. A 100 TSS ride needs roughly 24 hours of recovery. A 300 TSS ride might need 48-72 hours. Without this number, you are guessing at when your next hard session should be.

The trap is treating TSS as a target to maximise. More TSS is not better — appropriate TSS for your current fitness is better. A rider with a chronic training load (CTL) of 50 who suddenly does a 200 TSS day is overreaching. The same 200 TSS day for a rider with CTL of 80 is a normal hard day.

Where TSS becomes powerful is in tracking trends. Plot your weekly TSS over 12 weeks. If it rises 5-10% per week with a drop every fourth week, you are building fitness. If it is erratic — 600 one week, 200 the next — you are accumulating fatigue without building consistency.

EXPERT EVIDENCE

WHAT THE EXPERTS SAY

Dr Andrew CogganExercise physiologist, co-developer of TSS, normalised power, and IF
TSS was designed to provide a single metric that accounts for both duration and intensity of exercise, normalised to the individual's threshold. The key innovation is intensity factor (IF), which scales the training load relative to the rider's capacity rather than using absolute power values.
Hunter AllenCycling coach, co-author of Training and Racing with a Power Meter
Weekly TSS should increase by no more than 5-10% per week during build phases. Chronic Training Load (CTL), the rolling 42-day average of daily TSS, is the closest proxy for fitness we have. A CTL increase of 3-5 points per week is sustainable for most amateur cyclists.

PRACTICAL APPLICATION

DO THIS WEEK

Know your TSS benchmarks by session type
Easy zone 2 ride (90 min): 60-80 TSS. Sweet spot intervals (75 min): 80-100 TSS. VO2max intervals (60 min): 70-90 TSS. Long endurance ride (4 hours): 180-250 TSS. Use these as targets to gauge whether your sessions are hitting the intended load.
Track weekly TSS and keep it progressive
Sum your daily TSS into weekly totals. Aim for 5-10% increase per week during build phases, with every fourth week reduced to 60% of the prior week (recovery week). For most riders training 8-10 hours per week, 350-500 weekly TSS is typical.
Monitor your Training Stress Balance (TSB)
TSB = CTL minus ATL. Positive TSB means you are fresh; negative TSB means you are fatigued. For events, taper until TSB is between +10 and +25. For training, work at TSB between -10 and -30 — negative enough to stimulate adaptation, not so negative you are overreaching.
Use TSS to plan recovery
After a ride of 150+ TSS, allow at least 36-48 hours before the next hard session. After 300+ TSS (a big event or long ride), plan 2-3 easy days. The recovery need scales non-linearly — a 300 TSS day costs more than three 100 TSS days.

COMMON MISTAKES

WHAT CYCLISTS GET WRONG

MISTAKEChasing high TSS numbers as a goal in themselves.
FIXTSS is a measure of load, not quality. A 200 TSS ride from spinning easy all day is not the same stimulus as 200 TSS from structured intervals. Match TSS to your training objectives.
MISTAKEUsing TSS without an accurate FTP.
FIXTSS is calculated relative to FTP. An outdated or inflated FTP makes every TSS number meaningless. Retest FTP every 6-8 weeks and after any extended break.
MISTAKEIgnoring the relationship between acute and chronic load.
FIXA single high TSS day is manageable if CTL is high. The same TSS day on low CTL is a recipe for illness or injury. Always contextualise individual session TSS against your training history.

FAQ

FREQUENTLY ASKED QUESTIONS

Can I calculate TSS without a power meter?

Heart-rate-based TSS (hrTSS) is an estimate available in most platforms. It is less accurate than power-based TSS because heart rate lags effort and is affected by heat, caffeine, and fatigue — but it provides a reasonable approximation.

What is a good weekly TSS?

For amateur cyclists: 200-350 (recreational), 350-500 (competitive amateur), 500-700 (serious racer). Professionals routinely exceed 800-1,000 weekly TSS. The right number depends on your training history and goals.

Does TSS account for strength training?

Standard TSS does not include off-bike work. Some platforms offer gym-based TSS estimates, but they are rough. Track strength sessions separately and factor them into your overall fatigue management.

What is the difference between TSS and IF?

Intensity Factor (IF) is the ratio of normalised power to FTP — it measures how hard a ride was relative to your capacity. TSS uses IF plus duration to measure the total cost. A short, hard ride has high IF but moderate TSS; a long, easy ride has low IF but high TSS.

How does TSS relate to RPE?

TSS and RPE (rate of perceived exertion) often correlate, but they can diverge. A ride in the heat or when fatigued will feel harder (higher RPE) than the TSS suggests. Use both: TSS for objective load tracking, RPE for subjective fatigue monitoring.

Can TSS predict overtraining?

A rapidly increasing CTL (more than 7-10 points per week) or sustained negative TSB (below -30 for more than two weeks) are warning signs. TSS does not directly diagnose overtraining, but it flags the loading patterns that precede it.