The coach I wanted for my own training
IntervalCoach is built by Martijn Russchen, an endurance athlete and software engineer, for anyone who trains with a watch and a goal: cycling, running, triathlon, swimming, strength and HYROX.
Our promise
IntervalCoach is a daily-adaptation engine. Before each session, the system reads more than 60 recovery and training-load signals from your devices: HRV, sleep, resting heart rate, fatigue, recent load. It then either confirms today's plan, dials it back, or replaces it. No static templates, no guessing.
Underneath the daily adjustment sits a real periodization roadmap. The engine supports five established models (linear, undulating, polarized, pyramidal, and block) and steers your training across cycling, running, swimming, walking, hiking, and strength so that long-term progression keeps moving even when individual days have to bend.
About the founder
I've been cycling seriously for over fifteen years. Road, gravel, the occasional race, and a lot of structured training in between. Like most data-driven athletes I tried just about everything: paid coaches, generic plan apps, hand-tuned spreadsheets, and Intervals.icu for the analysis side. The pattern was always the same. The plan looked great on Monday. By Wednesday I'd slept badly, gotten sick, traveled for work, or just felt off, and the plan didn't care. I'd either ignore it and feel guilty, or push through and pay for it later. None of the apps actually looked at how I felt that day before deciding what to prescribe. IntervalCoach started as the coach I wanted for myself: something that reads my recovery data every morning and adjusts the session before I see it. No begging an algorithm to skip a workout, no manual replanning. It's grown well beyond that now, but the core question is still the same — what should I actually do today, given the body I'm in today? I ship new things every week, mostly driven by what I run into in my own training and what other athletes ask for. I'm still figuring out where it's all going, but I'm enjoying finding out. — Martijn
Grounded in science
Every workout the system writes pulls from established sport-science methodology, not generic AI advice.
Five periodization models
Linear · Undulating · Polarized · Pyramidal · Block
Recovery metric families
HRV, sleep duration and quality, resting heart rate, training load (CTL/ATL/TSB), and subjective wellness markers like RPE, mood, and soreness.
All adaptations are grounded in peer-reviewed training literature.
Representative literature
- Benefits and Limitations of Block Periodized Training Approaches to Athletes' Preparation: A Review — Sports Medicine, 2016
- Biological Background of Block Periodized Endurance Training: A Review — Sports Medicine, 2019
- Performance and Physiological Effects of Race Pace-Based Versus Heart Rate Variability-Guided Training — Medicine & Science in Sports & Exercise, 2025
- Heart rate variability-guided training in professional runners: Effects on performance and vagal modulation — Physiology & Behavior, 2022
By the numbers
Each day the engine watches 60+ recovery signals, applies one of 5 periodization models, and supports 9 sports (cycling, running, trail running, swimming, triathlon, strength, HYROX, walking and hiking) across 25 languages: English, Dutch, German, Spanish, Italian, French, Polish, Portuguese, Czech, Slovenian, Danish, Swedish, Norwegian, Finnish, Hungarian, Greek, Romanian, Slovak, Latvian, Lithuanian, Estonian, Simplified Chinese, Traditional Chinese, Japanese, and Korean. Pricing is €3 to €8 per month, a fraction of comparable AI coaching tools, and new features ship every week.
Works with
Apple Health · Google Health · Whoop · Intervals.icu · Garmin · Polar · Wahoo · Oura · and more
As featured in
the5krunner: “AI Training That Adapts to Your Recovery Each Day”
the5krunner: “IntervalCoach Race Recon: training and fuelling from a GPX file”
Common questions
What is IntervalCoach?
IntervalCoach is an AI training coach for cycling, running, triathlon, swimming, strength and HYROX. Before each session it reads over 60 recovery signals — HRV, sleep, resting heart rate and training load among them — and adjusts the day's session when the data calls for it, then syncs it to your Intervals.icu calendar and on to your head unit.
Who builds IntervalCoach?
Martijn Russchen, an endurance athlete and software engineer who built the coach he wanted for his own training. New features ship every week.
Which recovery signals does IntervalCoach watch?
Over 60 signals, evaluated together rather than one at a time: HRV with coefficient-of-variation tracking, sleep duration and quality, resting heart rate, training load (CTL/ATL/TSB), SpO2, skin temperature, ACWR, consecutive training days, subjective wellness markers such as mood and soreness, your post-workout RPE feedback, and aerobic durability. Compound patterns carry more weight than any single number.
Which periodization models does IntervalCoach use?
Five: linear, undulating, polarized, pyramidal and block. The model applied depends on your goal, your current fitness and where you are in the season.
Is IntervalCoach grounded in sports science?
Yes. Every workout the system writes pulls from established sport-science methodology rather than generic AI advice, and all adaptations are grounded in peer-reviewed training literature.
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