FeaturesMembershipBlogLog inSign up

Everything that measurably improves your training

What trace calculates from your sessions, in four chapters. On the web and in the app.

PerformanceRecovery & HealthPlanning & CoachingNutrition

Chapter 01

Performance

What your engine puts out, how long it holds, and where it breaks down. Seven engines that rebuild your performance profile from every session.

Every session in full detail.

Critical Power

90 days
5 s1 min5 min20 min60 min
freshfatigued after 20 kJ/kg

CP

287W

W′

15.2kJ

R² · High confidence

0.99

Critical Power & W′

See exactly where your strengths and weaknesses lie. trace calculates your power curve in real time from all imported activities and tracks your progress over weeks and months.

More details
  • CP and W' from the hyperbolic model – more precise than FTP estimates
  • Power Duration Curve from 5s to 60min, absolute or in W/kg
  • Fatigued curve after 20 kJ/kg of work, right next to the fresh one
  • Model confidence and the date of your best efforts, so you know how solid the number is

W′ balance

Ride · 3:23 h

Green > 60% · Yellow 30–60% · Red < 30%

Attacks

19

Lowest point

0%

Above CP

60:16min

W′ balance

Every effort above your Critical Power drains your anaerobic reserve. During easy phases it recharges. trace shows you on every ride how much reserve you have left and when you're entering the red zone.

More details
  • Green above 60%, yellow from 30 to 60%, red below 30%
  • Matches automatically detected and rated
  • Recovery time after each match calculated
  • Based on the Skiba W'Balance model (2015)

Durability

Good

94%

1 min
97 %
5 min
95 %
10 min
93 %
20 min
91 %

Fatigued against fresh, per duration

Durability

Anyone can ride fast when fresh. trace compares your power curve in a fresh state with the one under fatigue and calculates your Durability Score. This is the metric that separates WorldTour riders from ProTeam riders.

More details
  • Fresh vs. Fatigued Power Duration Curve – side by side
  • Durability Score from 0–100% – track your improvement over months
  • Automatically calculated from your ride data, no special test needed
  • Based on current research (Mateo-March, Leo, van Erp et al.)

Aerobic efficiency

Solid base

6.2%

Decoupling, 28-day median

ExcellentGoodBuildingWeak

Z2 Efficiency

1.82W/bpm

Sessions

14

Best Session

2.1%

Aerobic efficiency

Over a long session your heart rate climbs even though power stays flat. How far it drifts tells you how solid your aerobic base really is. trace measures it in every long session and tracks the trend.

More details
  • Aerobic decoupling (Pa:HR) per session and as a 28-day median
  • Z2 efficiency in W/bpm (bike) or m/beat (run), week by week
  • Robustness filters: sessions that are too short, too erratic or heat-affected do not skew the trend
  • Clear banding from "very strong base" to "base still missing"

VO₂max

Cycling53Very good
253545556575
Running50Very good
253545556575
Fitness age20at 34

VO₂max

No lab test, no chest-strap ritual. trace estimates your maximum oxygen uptake from the riding and running you already do – separately for each sport, tracked across the season.

More details
  • Several estimators combined: power-based, heart-rate-based, best-effort
  • Separate values for bike and run, each rated against age and sex norms
  • Fitness age: what your number means compared to the general population
  • Time off training lets the value decay realistically instead of freezing

Climbs

KesselbergCat. 24×18:42

Length

4.2 km

Avg. grade

7.4 %

VAM

1180

W/kg

4.8

KaunertalHC2×1:34:10

Length

26.1 km

Avg. grade

6.1 %

VAM

1020

W/kg

4.2

HerzogstandCat. 37×11:03

Length

2.8 km

Avg. grade

8.9 %

VAM

1240

W/kg

5.1

Climbs

trace detects every climb automatically from your elevation and GPS data, categorises it from HC to Cat. 4, and recognises it again when you ride it two years later. Every time, every W/kg, every VAM.

More details
  • Detected and named automatically – no segment to create
  • Categories from HC to Cat. 4, virtual climbs flagged separately
  • Best time, VAM and W/kg per ascent, with the delta to your PR
  • Overview map of all your climbs plus the history across every repeat

Running analysis

Critical Pace

3:52/km

Pace zones

Z1Z2Z3Z4Z5

VDOT

54.2

10K forecast

39:12

HR recovery

−32bpm

Running analysis

Running is not cycling in different shoes. trace has a dedicated engine for it, with Critical Pace instead of Critical Power, GAP instead of raw pace and rTSS instead of TSS, plus everything modern running watches capture on dynamics.

More details
  • Critical Pace and pace zones from your actual runs
  • GAP: grade-adjusted pace, so hilly runs become comparable
  • VDOT and race prediction from 5K to marathon
  • HR recovery and training effect after every run
  • Running dynamics and trail metrics as a trend

Chapter 02

Recovery & Health

Training only works if you recover. trace tracks how rested you are, how much load you carry, and how well you handle the heat.

Your training, finally understood.
Stay on top of form, fitness and fatigue.

Readiness

82/100

Recovered

Your recovery numbers hold up and your form is positive. A demanding session is well within reach today.

HRV · Normal

62ms

Resting HR · Stable

52bpm

Sleep · Good

7.5h

Readiness score

trace reads your health data every night and calculates whether you're ready for hard training. No manual input, no guessing.

More details
  • Automatic from your watch: HRV, resting HR and sleep, plus sleep stages and stress where the device provides them
  • Readiness from 0–100 with concrete training recommendations
  • HRV trend over weeks – spot positive adaptation or overload
  • Optional: add muscle soreness and mood manually (5 seconds)

Training load

Fresh

Fitness

72+12

Fatigue

58+3

Form

+14+9

Training load

Training Stress Balance gives you an objective picture of your current shape. trace calculates fitness (CTL), fatigue (ATL), and form (TSB) from every session – so you know when to push and when to hold back.

More details
  • Daily updates to fitness, fatigue, and form
  • Early warning when load rises faster than you can absorb it
  • History over 7, 30, 90 or 365 days
  • Monotony and strain, with a note when the week gets too uniform
  • ACWR – shows if your training ramp is too aggressive
  • Outlook on how fitness and form develop with rest over the next 14 days

Heat acclimatization

78/ 100Well acclimatized
5 hot sessions (14 d)2 days ago

Feels like

31°

Humidity

62 %

Data quality

High

Heat acclimatization

Heat costs you power, but the body adapts. trace turns the temperature and humidity of every session into a heat dose, builds an acclimatization level from it, and shows how quickly it fades once the weather cools.

More details
  • Level from 0 to 100, from "not acclimatized" to "fully acclimatized"
  • Heat dose from temperature, humidity and duration of each individual session
  • Realistic decay: without hot sessions your level drops again
  • Your VO₂max estimate is corrected for the heat effect
Ridley road bike in full flight – precision and speed

Data that makes
you faster.

trace turns your training data into concrete pointers for your next session.

Chapter 03

Planning & Coaching

From season structure to the weekly plan to race day. Plus a coach that knows your data.

A plan that adapts to you.
A coach that knows your data.

I slept badly. Should I still do the intervals today?

trace Coach · AI

Keep it easy today. HRV and resting HR are below your normal range. The intervals will do more for you tomorrow.
Read for this answerRecovery over 60 daysPlan week 5

Move the intervals to tomorrow

Today 60 min easy in zone 2, the VO₂max session moves back a day.

ApplyDismiss

trace Coach

Ask trace anything. The coach reads your sessions, your form and your health data and answers with your numbers. When the plan does not fit, it proposes a change, and you decide.

More details
  • Shows under every answer what it read for it
  • Remembers your goals and limits across conversations
  • Plan changes as proposals you apply or dismiss

Training plan

Week 5 · Build

Mon

Rest

–

Tue

1:30

Wed

1:10

Thu

1:00

Fri

Rest

–

Sat

3:30

Sun

0:45

Training plans

trace builds a training plan from your goals, your current fitness and your available time. When form, readiness or how you felt (RPE) do not fit the plan, trace proposes a change and you confirm it.

More details
  • Visual calendar showing planned vs. completed training
  • Proposals to soften, swap or rebalance when the week does not fit
  • Built in blocks with recovery weeks

Today

Readiness 82

Endurance ride

1:30 h · 67 TSS

From the catalogue

Sweet spot 3 × 15VO₂max 5 × 4Threshold 4 × 10

Training for today

Even without a training plan, trace suggests a session every day. From Athlete you pick your own from the workout catalogue, every day and without a counter.

More details
  • Daily suggestion from Starter, even without a plan
  • Workout catalogue with ready-made sessions from Athlete
  • Every session with structure, zones and targets

Workout builder

Threshold 3 × 8
3 ×
Warm-up10 minWork8 minRest4 minCool-down10 min

Workout builder

Build your own workouts from warm-up, intervals, sets, ramps and cool-down, or import them from a workout file. With Pro.

More details
  • Sets with repeats, ramps and fixed targets
  • Import from ZWO, ERG, MRC, FIT and TCX
  • Your own workouts land in "My workouts"

Insights

This week

Record

New 20-minute best: 318 W (+6 W).

Load

This week is 24 % above your average. Plan an easy day.

Recovery

HRV above your mean three days running. The base is holding.

Insights

Instead of making you hunt for numbers, the findings come to you. Rules check your consistency, load, records, recovery and races every day and surface only what actually matters.

More details
  • Rule-based and traceable, not just generated AI prose
  • Weekly recap, new records, warning signs and concrete recommendations
  • Per-session detectors: what was remarkable about this particular ride?

Course

Ötztaler Radmarathon
232 W268 W215 W254 W

Forecast · Range 7:54–8:36

8:12h

Fueling

72g carbs/h

Lowest W′

24%

Course & races

Upload your course and trace works it through with your numbers, with a power target per section, W′ balance along the course, fueling and a time forecast with an error band. For race day, form on the day, the taper and the debrief afterwards come on top.

More details
  • Race readiness score with risk cards for what is still missing
  • Performance prognosis from your actual profile, not from wishful thinking
  • Pacing and fuelling strategy for the specific course
  • Taper plan that drops straight into your training plan
  • Post-race debrief: what worked, what did not, and what it means for next time

Chapter 04

Nutrition

Your needs follow your training. trace works out your daily targets, fueling during sessions and a weekly plan with a shopping list.

Daily targets

Interval day
3,190kcal
Carbs456 g
Protein134 g
Fat92 g

Daily targets

What you need depends on what is on the plan today. trace combines basal metabolism, training burn and everyday activity into your targets for the day.

More details
  • Calories, carbs, protein and fat, scaled to the training day
  • Energy availability as a warning signal against chronic underfueling

Fueling

3 h ride

72

g carbs per hour

0 h1 h2 h3 h

every 20 min

BottleGelBar

Fueling during sessions

For long sessions and races, trace works out how many carbs per hour you need and plans your race-day fueling.

More details
  • Carbs per hour for long sessions and races
  • Race fueling for your course

Weekly plan

MonPorridge · Pasta with salmon3,180
TueYoghurt bowl · Rice with chicken2,640
WedPancakes · Gnocchi with spinach3,420
ThuMuesli · Lentil curry2,510

Shopping list · 26 items

Weekly plan

From your daily targets, trace builds seven days with meals, recipes and a shopping list.

More details
  • Recipes that match your macro targets
  • A shopping list for the week, for several people too
Compatible with your devices

From your device straight into trace.

Connect once and every session arrives on its own. COROS, Zwift and others come in through Intervals.icu.

connect powered by GarminWahooHammerheadROUVY
PolarSuuntoWorks with Apple HealthIntervals.icuIntervals.icu
Intervals.icu
Intervals.icu
Intervals.icu

The Fundamentals

The basics any training platform has to get right, wired into the engines above.

Analysis

Zones
Heart rate and power per session and across the season, optionally from your Critical Power.
Personal records
Records from 5 seconds to 60 minutes, detected on every import.
Power values & FTP
NP, IF and TSS per session. A new FTP applies at once to zones, plan and analyses.
Activity detail
Map, laps and every stream, plus how the session felt (RPE) for the plan.
Workout report
Planned versus actual after every scheduled session, with a score and a pointer.
Rider type
Your profile across five durations, compared up to elite amateur.

Around your training

Season overview
Phases, goals and the highlights of your year in one place.
Gear
Bikes with wear parts, running shoes with their own mileage.
Coach & team
Your coach sees your dashboard, leaves notes and chats with you.
Integrations
Garmin, Wahoo, Polar, Suunto, Hammerhead, ROUVY, Apple Health, Health Connect and intervals.icu.

The comparison on the pricing page shows what each plan includes. View pricing

trace – Your training. Finally truly understood.

Product

  • Features
  • Pricing
  • Blog
  • App

Company

  • About
  • Support
  • Sign in

Legal

  • Terms & Withdrawal Instructions
  • Privacy
  • Legal Notice
  • Cancel contracts here
  • Withdraw from contract
  • Delete account
© 2026 trace · All rights reserved