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What Is TSS? How Weekly Training Load Really Works

Every key session done. Great sleep. Low life stress. Sessions feeling easier than expected. On paper, a green light.

Their coach said hold steady. Here is why, and what it teaches you about training load.

Photo: Ben Creswick, IRONMAN 70.3 Victoria

What does TSS measure?

Two ingredients: how long and how hard. TSS combines them into one score, so a long easy ride and a short hard run sit on the same scale.

How long
+
How hard
=
TSS

One score for one workout. Add a week of them and you have your weekly load.

Bikepoweragainst your Critical Power
Runpaceagainst your Critical Speed
Swimdistanceone consistent method all season

This is why testing matters. If your CP or CS is out of date, every score built on it is off, and so is every decision that follows.

What are fitness, fatigue and form?

CTLFitnessyour load over roughly the last six weeks
ATLFatigueyour load over roughly the last week
TSBFormthe gap between the two
TSB
Form
=
CTL
Fitness
minus
ATL
Fatigue

Form is the gap between fitness and fatigue.

In a building phase, TSB below zero is normal. What we watch is the trend. A sharp, sustained slide tells us fatigue is outrunning recovery.

Bike and run are tracked separately. A strong bike base does not mean your legs are ready for more running. See how to split your hours when life is full.

What it looks like for a real athlete

Ben Creswick, TrainingPeaks fitness, fatigue and form, July to Oct 31

Real fitness, fatigue and form chart from TrainingPeaks
Fatigue (grey) swings week to week. Fitness (navy) moves slowly. Form (orange) climbed above plus 30 before each of his two races. Tap to open full size.

Weekly TSS, sport by sport

Ben Creswick, TSS per week from TrainingPeaks

Real weekly TSS by sport from TrainingPeaks
The same week can be mostly bike or mostly run. That is why we read load for each sport. Tap to open full size.
Katy's Performance Management Chart, straight from TrainingPeaks
Katy's Performance Management Chart, straight from TrainingPeaks. Tap to open full size.

Why was the green light week a hold?

A real week: the green light that was a hold

OKEvery key session completed
OKGood sleep
OKLow life stress
OKSessions felt easier than expected
!Fatigue well above fitness
!Race specific block
Coach decision: HOLD STEADY
Protect the next several weeks, not win one.

The athlete was in a race specific block. Fatigue had climbed well above fitness, and in that block it carries real risk.

The load picture outweighed a great week of feel. Protecting the next several weeks mattered more than winning one.

Another athlete ran a steady easy hour in heat they were not used to. The file scored it as ordinary. Their coach credited it as more stressful than it looked, so the next week was not set too high.

A real session: one easy hour in unfamiliar heat

What the file said
Scored as an ordinary session
What the coach saw
Credited as more stressful than it looked

Result: next week was not set too high.

Why aren't the numbers enough?

Two athletes can finish the same week with the same score. One is adapting. The other is quietly digging a hole.

The data shows
Duration and intensity
Fitness, fatigue, form
Power, pace, heart rate
Only you can tell us
Sleep
Soreness
Mood and motivation
Life stress

So sleep, soreness, mood, motivation and life stress sit beside the data every week. Heart rate and HRV are read together with power, pace and feel, never alone.

Weekly run training stress from TrainingPeaks across the build
Weekly run training stress from TrainingPeaks across the build. Tap to open full size.
Ben Creswick, IRONMAN 70.3 Victoria
Ben Creswick, IRONMAN 70.3 Victoria
Ben Creswick, IRONMAN 70.3 Victoria
Ben Creswick, IRONMAN 70.3 Victoria
Holly Koksel at the Anchor Down Ultra
Holly Koksel at the Anchor Down Ultra
Katy Walmsley at the Garden State Swim Run
Katy Walmsley at the Garden State Swim Run

How is your weekly load set?

Each week starts from your current fitness in each sport. Then your coach decides: push, hold or pull back, and by how much.

Fatigue vs fitness
Where form is heading
How key sessions went
Life outside training
â–¼
Your coach decides
â–¼
Push
Hold
Pull back

Recovery works the same way. Some athletes are ready to keep building past where a calendar would schedule rest. Others need it sooner. Your data and your feedback decide. Learn the fatigue signs to track.

Holly's fitness, fatigue and form from TrainingPeaks, with Anchor Down and IRONMAN Maryland marked
Holly's fitness, fatigue and form from TrainingPeaks, with Anchor Down and IRONMAN Maryland marked. Tap to open full size.

What does an ANC athlete actually get?

Every ANC coach works from one shared method, StressLogic. It is a loop, not a formula, and it runs every week.

Step
Evaluate
What your coach does
Reads load trend, sessions, sleep, life
Step
Calibrate
What your coach does
Sets next week: push, hold, pull back
Step
Harmonize
What your coach does
Balances bike, run, swim and recovery
Step
Optimize
What your coach does
Reads your response and adjusts

Testing. Your CP and CS are tested and kept current, so every score means something.

Decisions. Like the green light week above, the call comes from the whole picture. A great feeling week does not override a risky load trend, and a clean file does not hide a hot day.

The feedback loop. Your notes sit beside your data. Sleep, soreness, mood and the week you are really having all change what comes next.

Weekly training stress. Specificity started about six weeks from each race
Weekly training stress. Specificity started about six weeks from each race. Tap to open full size.

What does coaching with ANC feel like?

It feels like opening your week and trusting it. Knowing a hold is protecting your next month, not holding you back. Knowing a push is coming because you earned it.

It feels like never making up a missed session in a panic, and never guessing whether you need rest. Someone is reading your week with you, and every number finally has a reason.

A plan is written once. An app can total your TSS. Neither can sit with your week and ask what it really cost you. A coach can, every week. See it in action in Katy Walmsley's Boston PR.

What Is TSS? How Weekly Training Load Really Works

Photo: Katy Walmsley at the Garden State Swim Run

TSS and training load FAQ

What is TSS in triathlon?

TSS is a single score for the stress of one workout, combining duration and intensity. Bike TSS uses power against Critical Power, run TSS uses pace against Critical Speed, and ANC scores swims by distance.

How much weekly TSS do I need for an IRONMAN or 70.3?

There is no fixed number by race distance. ANC sets weekly load from your current fitness in each sport, then adjusts it every week based on how you are absorbing training.

Should I make up a missed workout?

No. Missed training is part of your history, and cramming it back in tends to compromise the sessions that follow.

How do I know when I need a recovery week?

Watch for a worsening fatigue trend together with poor sleep, rising soreness, falling motivation or sessions that stop going well. At ANC, recovery is prescribed from those signals, not from a fixed calendar.

Train with someone reading your whole week.

Tell me about your goal and your season. We'll start from there.

Or see how StressLogic works.

angelanaethcoaching.com

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