Comparison
STAS vs Runna — which AI running coach fits you?
Two different approaches to AI coaching. Runna gives you ready-made plans in a polished app. STAS lets you start quickly through Intervals.icu — then ask ChatGPT or Claude about your actual training, adding more personal context later.
What is Runna?
Runna is a popular AI running coach app that generates structured training plans based on your goal race, current fitness level, and available days. It integrates with Garmin, Apple Watch, and Strava to pull in your workout data and adjust plans accordingly.
The app is known for its clean interface, well-organized training calendar, and guided workouts. It works best for runners who want a ready-made plan they can follow without much deliberation. Runna is a paid subscription service, typically around $15/month.
What is STAS?
STAS is a real-data AI coach that connects directly to your Intervals.icu account. For the first useful result, Intervals.icu plus one AI chat is enough: STAS already sees your training history, recent load, and calendar.
Later, you can add profile, goals, rules, and reports to make the coaching more precise and more consistent over time. But you can start right away with recent workouts, current condition, the next few days, or a new plan. STAS has a free tier available.
Side-by-side comparison
Runna
- Approach
Mobile app with structured training plans and guided workouts - Data source
Garmin, Apple Watch, Strava sync - Plan adaptation
Weekly plan adjustments based on completed workouts - Conversation
No free-form chat with the coach - Life context
Limited — select from predefined options - Price
~$15/month subscription - Explainability
Limited — follow the plan as given - Best for
Beginners wanting clear structure and guidance
STAS
- Approach
Conversation through ChatGPT or Claude powered by your real training data - Data source
Deep Intervals.icu integration (HR, pace, CTL/ATL/TSB, laps) - Plan adaptation
Real-time per-workout adjustments based on actual performance - Conversation
Full natural language — ask anything about your training - Life context
Can factor in illness, travel, fatigue, and schedule changes when you tell it and when the context exists - Price
Free — you pay only for your ChatGPT or Claude chat - Explainability
Ask "why this workout?" and get a detailed answer - Best for
Endurance athletes who care about data, control, and transparency
When Runna is the better choice
Runna is a strong option if you value a polished mobile experience and prefer following a structured plan without much back-and-forth.
- •You want a clean, guided app experience with workout instructions on your wrist
- •You're new to running and prefer a plan you can follow without decisions
- •You don't use Intervals.icu and sync primarily through Garmin or Strava
- •You prefer a visual training calendar over conversational coaching
When STAS is the better choice
STAS fits runners who want a fast start from real data, with the option to make the coaching more personal and more precise over time.
- ✓You want to start quickly with Intervals.icu and one AI chat, then add more personal context later
- ✓You want to ask questions, discuss strategy, and understand the reasoning behind each workout
- ✓Your schedule changes often — illness, travel, variable workload — and you need real-time adaptation
- ✓You want a more personal coaching layer, not just a weekly list of workouts
Frequently asked questions
Can I use both Runna and STAS at the same time?
Technically yes, but it's not recommended. Following two different training plans simultaneously creates conflicting load and recovery signals. Pick one approach and stick with it for at least a training cycle.
Does STAS work without Intervals.icu?
Intervals.icu is the core data source for STAS. Without it, STAS can't access your training history, HR zones, or performance metrics. If you use a Garmin, Wahoo, or other device, you can connect it to Intervals.icu for free — it takes about 2 minutes.
Is Runna better for beginners?
Runna's structured approach with guided workouts and a clean app interface can be more approachable for beginners. STAS is more powerful for runners who want to go deeper, but the conversational format works well at any level — you just ask simpler questions.
Why is STAS free when Runna charges $15/month?
STAS itself is free. After that, you only pay for the AI chat you choose — ChatGPT or Claude. STAS gives you the data bridge and the coaching logic on top.
Related
Start with real data, not a template
Connect Intervals.icu and start asking ChatGPT or Claude about your actual training. Profile, goals, and reports come later if you want more precision.
Connect Intervals.icuFree to start. No credit card required.