Public betaTraining analytics for athletes and coaches
Train Arc computes training load, fitness, fatigue, and form from your rides, runs, and swims, flags personal records, and matches completed sessions to your planned workouts.
Product tour
Three short videos built from screens of the app with its demo data: an athlete with two months of rides, runs, swims, and strength sessions, and a coach who works with them.
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Overview
The main screens for athletes and coaches, with the demo athlete's data.
Intervals, fitness and form, race-day projection, Arc, the coach's weekly review
Features
Each new session updates your load, time in zones, records, readiness, and plan matches.
Load & form
Rides are scored with power TSS, runs with pace (rTSS), and swims with swim speed (sTSS). Without those, and for other sports, heart-rate TRIMP is used. Daily load feeds a 42-day fitness and a 7-day fatigue average, and form is the difference. The Training trends page also compares your last 7 days with the 21 before and tracks monotony and strain.
Recovery
A daily score out of 100 from your recent load. Same-day HRV and sleep from WHOOP or Garmin, and WHOOP's recovery score, can move it, and the app lists what did.
Zones & records
Heart-rate zones come from your threshold heart rate, power zones from your FTP. Each new workout updates your mean-max power curve and is checked for records, such as best 20-minute power or fastest 10 km.
Planning
Put structured workouts with power, heart-rate, pace, or RPE targets on your calendar. When a session comes in, Train Arc matches it to the plan and scores its duration, distance, TSS, and elevation against it.
Analyzer
Overlay power, heart rate, cadence, and speed from different devices on one timeline. Shift a recording to line it up, smooth the traces, and compare each one's mean-max power curve.
Sync & files
Upload a ZIP of your history, such as a Strava or Garmin export, or loose FIT, TCX, and GPX files. Connected Strava, Garmin, and WHOOP accounts sync new sessions. Uploaded files are kept as sent, and Train Arc flags duplicate recordings so you choose which one counts.
Live model
Pick a plan shape and an average weekly load for the 16 weeks before a race. Fitness, fatigue, and form are computed in your browser with the formulas the app uses.
Plan shape
Race morning
Fresh on race morning: form is +24% of fitness.
Race morning after the Build, then taper plan at 550 TSS a week on average: fitness 75.5, fatigue 57.6, form +17.9, fresh.
Computed with the app's load model: fitness is a 42-day exponentially weighted average of daily TSS, fatigue the 7-day version, and form is yesterday's fitness minus yesterday's fatigue. Every shape plans the same total load.
Data flow
Workouts arrive as files or from connected accounts. Each one is parsed, checked for duplicates, scored, and added to your load and records. Select a source to trace its path.
Sources
Upload
Sync
Train Arc
Each workout
Each day
Where it shows up
Arc · AI assistant
Arc is a chat built into Train Arc. To answer, it looks up what it needs from your workouts, load, readiness, calendar, and goals.
In ChatGPT, with the Train Arc connector
“Add a 45-minute recovery spin to my Train Arc calendar on Monday.”
Added to Train Arc · Mon · Recovery spin · 0:45
Athletes and coaches
One account can use both. Switch between them in Profile.
Athlete mode
Your workouts, trends, recovery, calendar, and goals.
Coach mode
Invite athletes to your workspace. Each one accepts from their own account and can turn off any of the 13 permissions you get.
How it works
One upload or one connected account is enough to start. After that, each new session updates your load, records, and plan matches.
Upload a ZIP export or single FIT, TCX, or GPX files. Connecting Strava, Garmin, or WHOOP imports the last 3 months, then syncs new sessions.
Your FTP and threshold heart rate set your zones. With your threshold pace, they also set how each session's load is scored. A change applies from its date on.
Check your form before a hard day, put the next sessions on your calendar, and ask Arc about your week.
Yes, while Train Arc is in public beta: every account gets every feature. Sign-up asks for your name, email, and a password, not a card.
Any device or app that exports FIT, TCX, or GPX files. You can upload a ZIP of your history, such as a Strava or Garmin export, or connect Strava, Garmin, or WHOOP to sync new sessions. Uploaded files are kept, and you can download the original from each workout.
Fitness (CTL) is a 42-day exponentially weighted average of your daily training load, and fatigue (ATL) is the 7-day version. Form (TSB) is yesterday's fitness minus yesterday's fatigue: negative while you're building, positive when you're fresh. Rides are scored with power-based TSS, runs with pace-based rTSS, and swims with swim-speed sTSS. When those aren't available, and for other sports, load is heart-rate TRIMP, scaled so an hour at threshold heart rate scores 100.
It gives a daily readiness score out of 100, labeled Primed, Moderate, Easy, or Rest. The score starts from your form relative to your fitness. Same-day HRV and sleep from WHOOP or Garmin, and WHOOP's recovery score, can move it, and the app lists what did. It needs 7 days of training history, and it's a decision aid, not medical advice.
Only after you accept their invitation to a Coach workspace. Accepting gives the coach all 13 permissions, including activities, GPS routes, recovery, calendar edits, and messages. You can turn any of them off, or revoke access, in Profile under Coach access; changes take effect immediately. Separately, you can share a single workout or analyzer comparison as a read-only link.
A chat assistant built into Train Arc, for athletes and coaches. To answer, it looks up what it needs from your workouts, load, readiness, calendar, and goals, and each answer lists what it checked. Workouts it drafts stay in a preview until you add them to your calendar. For a coach, its tools are limited by each athlete's permissions. You can send up to 100 messages per 24 hours.
Yes. Enable the Train Arc MCP server under Connections, then add it as a connector in ChatGPT and sign in. ChatGPT can then read your training data. If you approve calendar access when you sign in, it can also add planned workouts, which go straight onto your calendar without a preview.
No. Train Arc runs in the browser on phone, tablet, and desktop, so there's nothing to install.
Free during beta
Upload a FIT, TCX, or GPX file, or connect Strava, Garmin, or WHOOP. Train Arc scores each session as it arrives and updates your fitness, fatigue, and form.