Justzone2
Zone 2 training
made simple
Control your Wahoo KICKR in ERG mode, stay in your heart rate zone, and sync with Strava. One app. One purchase. No subscription.
Control your Wahoo KICKR in ERG mode, stay in your heart rate zone, and sync with Strava. One app. One purchase. No subscription.
Real-time heart rate monitoring with visual zone indicators. Get alerts when you drift out of Zone 2.
Automatically control your Wahoo KICKR. Set your target power and the trainer does the rest.
Workouts automatically upload to Strava when you finish. Your training log stays complete.
No subscription required. Buy once, use forever. Save hundreds compared to monthly apps.
Watch Netflix, catch up on work, or listen to podcasts. Zone 2 is about easy effort, not full focus.
A PID controller monitors your heart rate every second and automatically adjusts your KICKR's resistance — keeping you locked in Zone 2 so you can focus on anything else.
A typical 60-minute session with Zone Targeting enabled
Heart rate is sampled every second from your Apple Watch or a BLE chest strap.
A PID controller computes the error from your Zone 2 midpoint. A gradient of the smoothed HR signal prevents premature power increases while HR is still climbing.
Your KICKR's resistance is nudged gradually — ramping up slowly and backing off faster when needed, keeping changes smooth and comfortable.
Every second, for the entire session. You keep pedalling and watch Netflix. The app keeps you optimal.
As aerobic fitness improves, your body sustains more power at the same heart rate. Because every Zone Targeting session is anchored to the same HR zone, average power becomes a direct, passive measure of fitness.
Average Zone 2 power over time — as fitness improves, the number goes up
It's how the pros build their aerobic engine.
Elite cyclists spend 80% of training time at low intensity. Zone 2 is where base fitness is built.
Train your body to burn fat as fuel. Improve metabolic flexibility and endurance capacity.
Zone 2 specifically targets mitochondrial biogenesis. More mitochondria = more power.
Easy effort means you can train more frequently without burnout. Build volume, not fatigue.
Curated videos and research on Zone 2 training
Understanding the science behind low-intensity endurance training
Why Zone 2 is the foundation of endurance performance
How to find your Zone 2 and structure your training
Deep dive into mitochondrial health and fat oxidation
Practical advice for getting the most out of your Zone 2 sessions
How to incorporate Zone 2 into your cycling training plan
Join athletes who train smarter, not harder.