AI Endurance Coach

Your watch records.
Coach understands.
You get faster.

An AI coach that actually reads your training data. Builds your plan. Adapts as you go. The first endurance coach that lives in your pocket.

Free forever tier Garmin · Apple · COROS · Samsung No credit card
Live coaching 13.94 km · long run · Saturday
Avg HR
136bpm
↓ Z2 zone held
Drift
+4.2%
strong aerobic
Time in Z2
78%
on target
Pace
5:21/km
conversational
C
Coach — Solid execution. You held under your Z2 ceiling (157 bpm) the entire run, and 4.2% drift confirms a strong aerobic engine. Tomorrow's recovery day will let you absorb this work. Keep building base.

Three steps to a smarter training week

From signup to coached workout in under three minutes. No coach, no spreadsheets, no guessing.

i

Tell Coach about you

Quick intake. Your goal, your time, your level. Coach uses this to design a plan calibrated to your life, not a generic template.

ii

Get your plan

Periodized training built on Friel's framework, your LTHR zones, and 80/20 distribution. Loaded into a calendar you can actually use.

iii

Train, upload, adapt

Upload after each session. Coach reads your data, comments on the run, and adjusts the plan when patterns emerge. You just train.

cardiac drift
LTHR zones
80/20 polarized
acute:chronic load
aerobic base
tempo
threshold
VO2 max
cardiac drift
LTHR zones
80/20 polarized
acute:chronic load
aerobic base
tempo
threshold
VO2 max

What others do. What we do.

Tools today record data. They don't coach you. Stryxs closes that gap.

Garmin
Records
Captures everything. Tells you nothing about what to change.
🧡
Strava
Cheers
"Nice run!" is not a training adjustment.
📊
TrainingPeaks
Displays
Numbers without meaning, unless you pay $300/mo for a coach.

Stop guessing.
Start training.

Free forever tier with unlimited analyses. Upgrade when you want long-term tracking and adaptive plans.

Stryxs · Built for athletes

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Welcome back

Here's your training overview

Recent Workouts
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Fitness Trend
Cardiac drift over time — lower is better aerobic fitness
Analyze Workout

Upload a workout file or connect your training platform for automatic syncing.

Supports Garmin, COROS, Polar, Suunto, Apple Watch exports (.csv)

Workout History

Every workout you've analyzed

Help & Getting Started

Everything you need to get the most out of Stryxs.

⌚ Exporting from Garmin
1
Go to connect.garmin.com on your computer.
2
Click Activities, then click any workout.
3
Click the ⚙️ gear icon in the top right.
4
Click Export to CSV.
5
Upload that file in the Analyze tab.
🍎 Exporting from Apple Watch
1
Open the Health app on your iPhone.
2
Tap your profile picture (top right) → Export All Health Data.
3
This exports a ZIP. For a simpler option, use a free app like HealthFit or RunGap to export individual workouts as CSV.
4
Upload the CSV in the Analyze tab.

Direct Apple Health integration coming soon.

⌚ Exporting from COROS
1
Go to trainingtoday.coros.com on your computer.
2
Click on any activity in your timeline.
3
Click the Export button and choose CSV.
4
Upload it in the Analyze tab.
📱 Exporting from Samsung Galaxy Watch
1
Open Samsung Health app on your phone.
2
Tap the menu (☰)SettingsDownload personal data.
3
Confirm and wait for the email with your data ZIP.
4
For individual workouts, third-party apps like Strava (auto-syncs Samsung) or FITWatch Sync can export CSV.

Direct Samsung Health integration coming soon.

🎯 Finding your LTHR

LTHR (Lactate Threshold Heart Rate) is the most important number for accurate zones.

1
Warm up for 15 minutes.
2
Do a 30-minute solo time trial at the hardest pace you can sustain.
3
Your average HR for the last 20 minutes is your LTHR.

Test run and bike separately. They differ by 5-10 bpm.

Frequently asked questions
What watches does Stryxs support?
Any watch that exports CSV, TCX, GPX, or FIT files — Garmin, Apple Watch, COROS, Polar, Suunto, Wahoo. Garmin is most common and best supported.
Will you add automatic syncing?
Yes — Strava integration is coming first (covers most watches since Strava auto-syncs them). Direct Garmin and Apple Health integration will follow.
Is my data private?
Yes. Your data is stored encrypted in our database. Only you can access it. We never share or sell training data.
How accurate are the analyses?
Based on published sports science: Friel LTHR zones, cardiac drift research, acute:chronic workload models. Accuracy depends on YOUR inputs — especially your LTHR. Test it properly.
What's the difference between Stryxs and Strava?
Strava is a social network for activities. Stryxs is a coaching analyzer. We turn data into coaching decisions. Strava doesn't.
What does it cost?
Free tier: unlimited analyses, 7 days of history. Pro ($15/mo): unlimited history, trend analysis, race planning, auto platform sync. Elite ($29/mo): Pro + injury risk scoring, nutrition periodization, race-day planning.
Settings

Edit your profile, training zones, and preferences.

Workout Details