I am excited to share Aixle (https://aixle.net), a new coaching tool built to work directly with your Intervals.icu data.
3 Daily Plans + Personalized Recommendations
Instead of a single prescribed workout, Aixle generates three distinct workout options every morning at 5 AM:
FTP (Threshold)
VO2max
Endurance (Zone 2)
It analyzes your current HRV trends, TSB (Form), and Power Profile from Intervals.icu to provide a Coach’s Score for each. This tells you exactly which session is most recommended for your current physiological state, while giving you the flexibility to choose based on your schedule.
Fully Automated Sync to Zwift
Auto-Upload: Generated .zwo files are automatically pushed to your Intervals.icu calendar.
Instant Access: Your workouts appear in your Zwift Custom Workouts folder the moment you start the app.
Coaching everyday for $2.99/mo
We believe data-driven coaching should be accessible to everyone. Aixle is priced at just $2.99/month.
Release Special for Intervals.icu Community
We offer a 7-day free trial (no credit card required to sign up). Additionally, use the coupon below to get a discount:
Coupon Code: AIXLESTARTER2025
Offer: 20% OFF for the first year
Validity: Redeemable through 2025
The core philosophy I want to push with Aixle is: Strict plans often break when life happens.
Instead of rigidly following a calendar set 4 weeks ago, Aixle recalculates the “Best Workout for Today” every morning. To make this decision more accurate, I’ve updated the API integration to pull Sleep Score, Sleep Duration, and Resting HR (in addition to HRV/TSB).
I wanted to share a quick update on Aixle (Coach for Intervals.icu). Thanks to the continuous feedback from our team of 30+ active Zwifters , the service has evolved significantly over the last few weeks.
Our development focus has been strictly on one philosophy: “Optimizing TODAY for your long-term goal.”
Fixed plans often break when life happens. We are building a system that adapts to your reality every single morning.
Here are the key improvements we’ve rolled out:
1. The “Anti-Monotony” Engine
Indoor training can be mentally tough. We found that often generated flat, boring recovery rides.
We have overhauled the generation logic to ensure “Mental & Physical Texture.”
Even for endurance rides, the now structures the workout into shorter blocks (max 5 mins).
It introduces specific Cadence Drills (e.g., alternating rpm) and micro-power fluctuations to keep you engaged and focused, rather than just spinning mindlessly.
2. Smarter Wellness Logic
We’ve refined how Aixle interprets your Intervals.icu wellness data (HRV, Sleep, Resting HR).
Freshness Matters: The system now strictly distinguishes between “No Data” and “Bad Data.”
Sync Pending Status: If your device hasn’t synced yet, Aixle recognizes this status instead of making assumptions based on old fatigue data. It ensures that “Today’s Recommendation” is always based on your current physiology.
3. Enhanced Dashboard & Daily Emails
We’ve upgraded the UI to give you a clearer picture of “Why this workout?”
The daily email now includes a clearer breakdown of your Fitness (CTL) vs. Form (TSB) .
The Dashboard visualizes your recent training distribution to explain how today’s session fits into the bigger picture.
We are running daily quality assurance cycles with our testers to ensure the generated .zwo files are not only physiologically correct but also fun to ride .
If you are looking for a dynamic plan that adjusts to “Today,” please give it a try! https://aixle.net
The quality of the automatic synchronization of Aixle-generated workouts to Zwift has also been improved to near perfection. They are automatically uploaded to Zwift every day.
New Year Update: Smarter Activity Detection & Logic Upgrades
Happy New Year holiday!
While you were riding (or resting) during the holidays, I’ve been coding to further refine the logic of Aixle .
Our goal is to move to more “Physiologically Logical Engineering.”
Here are 3 major logic updates deployed this week:
1. Robust “Yesterday” Detection
We noticed that sometimes very light recovery spins (Low Load) or delayed syncs were being misinterpreted as “Rest Days.”
I have completely rewritten the activity detection engine.
The Fix: It now cross-references timestamps and activity counts, not just “Load” numbers. Even if your ride was super light, the system knows you moved. The context for today’s suggestion is now bulletproof.
2. Adaptive Defaults based on Rider Level
When you don’t specify a duration or intensity preference, the system now calculates a personalized baseline target based on your current fitness (CTL).
One size does not fit all. Instead of a fixed default for everyone, Aixle scales the workout volume and density seamlessly:
It ensures advanced athletes get sufficient stimulus (e.g., allowing longer sustained blocks) while keeping durations manageable and engaging for developing riders.
Even without manual input, the plan is optimized for your current capacity.
3. Monthly Calibration (FTP Check)
It’s a new month. If you haven’t tested your FTP in 28+ days and your TSB indicates you are fresh, Aixle will now suggest a “Ramp Test” as one of your options during the first few days of the month.
Note: It won’t suggest this if you are fatigued.
Official Twitter (X) Account
We opened an official account to share development logs, logic explanations, and daily tips. https://x.com/Aixle_official
The logic is getting sharper every day by our test team.
HR vs Power: Currently, Aixle generates Power-based files (.zwo) specifically for Zwift ERG mode. We don’t support HR targets yet.
Swim/Run: We generate Bike workouts only. However, the system analyzes your Global Fatigue (including Swim/Run logs) from Intervals.icu to optimize your bike intensity.
I didn’t look closer at your .zwo files, but saw screenshots of the workouts…
I have a suggestion to you - for Zwift, generate workouts which consist manly of IntervalsT - these result in 20% more XP awarded in the game
Hi:
This is very cool and a very good example of data-driven approach to training. I have signed up and receive daily mail. Look forward to follow the project. Will try the workouts and follow the advices for some weeks.
One tip: It would be fine if the daily mail could visualize the recommendations. (picture of the workout or something). Just at tip
Hi!
Thank you for signing up and for the kind words.
Visualizing the workout structure in the email is a fantastic idea. I completely agree—it’s much more intuitive to see the graph.
I’ve added this to the development roadmap and will work on implementing a visual preview soon.
Thanks!
Actually, the system already generates for most interval blocks, but I honestly didn’t know about the specific XP bonus.
That’s a great insight, I’ll ensure we prioritize that tag to maximize value for users.
Delivery settings now support 15-minute increments (e.g., 6:15 AM).
This is crucial for morning riders who need a small window for their wearable data (Oura, Coros, Apple Health) to sync to Intervals.icu before the engine calculates today’s optimal session.
We’ve updated the logic to be more skeptical of activity labels.
Stats > Names: The engine now ignores activity names when reviewing your recent training.
Instead, it parses your raw Intensity Distribution data . Even if a ride is mislabeled as “Recovery” but your raw data shows significant time in Z5, the system will correctly identify the fatigue and adjust today’s plan accordingly.
The logic is getting sharper and more visual every day.
Thank you for your inquiry.
You said your workouts weren’t uploaded to Zwift, but were they uploaded to intervals?
I checked your settings and it says only your best workout is uploaded, so it’s normal for one workout to be uploaded to both intervals and Zwift.
I also checked the three .zwo files attached to the email, and they were successfully imported into Zwift. If you’re using a PC/Mac, you can access them by dropping them into Documents/Zwift/Workouts//.
If you wish, we can change your settings to upload all workouts.
Next, since intervals and Zwift are linked, please check your connection settings.
In Zwift, make sure “Upload planned workouts” is ON and you’re connected.
There’s a limit of about five uploads per day, but I don’t think that’s a problem.
Since it’s a link between services, it may not work properly for some reason. If that happens, download the zwo file from your email or the workout from intervals and save it in your Zwift workout folder.
February Update: Context-Aware Feedback & Deep Analysis Lifecycle
Hi everyone!
It’s been an active few weeks since our last update, and we’ve just rolled out several major features based on your feedback. We’re continuing to refine Aixle to be the smartest “morning of” bridge between your Intervals.icu data and your Zwift/MyWhoosh sessions.
The biggest logic leap this month is our enhanced Strava integration. While Intervals.icu provides the “Ground Truth” numbers (Load, Zones, HRV), Strava provides the “Story.”
Activity Context: Aixle now reads your Strava activity names and descriptions (e.g., “Spicy Group Ride” or “Legs felt like lead during hill repeats”).
Smarter Adjustments: The AI combines these qualitative feelings with your quantitative physiological metrics to provide much more nuanced feedback and precise intensity adjustments for today’s options.
2. Deep Analytics Dashboard
We’ve added a dedicated Analytics page to help you track your long-term progress without leaving Aixle.
Metric Trends: Visualize your weekly TSS, HRV trends, and Resting Heart Rate.
Performance Readiness: Monitor your CTL/TSB balance and training load distribution.
Power Distribution: See your weekly time-in-zone analysis to ensure you’re hitting your targets.
3. German Language Support
Guten Tag! Aixle is now fully localized in German, joining English, Japanese, French, and Spanish. Both the dashboard and the daily coaching emails are available in German to support our growing European community.
4. Apple Sign-in
To make onboarding even smoother for iOS users, we’ve added Apple Sign-in. You can now set up your account and start your free trial in seconds.
Our mission remains the same: Optimizing TODAY for your long-term goals. By combining the raw power of Intervals.icu with contextual data from Strava and advanced AI, we’re making personalized coaching more accessible than ever.
Check out the new features and let us know what you think!
Official Twitter (X) Account
