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Theron is an adaptive triathlon training app that builds a dynamic swim, bike, and run schedule from your wearable and health data. Unlike a static PDF plan that stays frozen even when you sleep poorly or miss a session, Theron recalculates daily workouts using heart rate variability (HRV), sleep, and recent activity from Apple Health, Apple Watch, Garmin, Wahoo, or Strava. The scheduling logic follows the same impulse-response idea used in Banister’s fitness–fatigue model (Banister et al., 1975): training raises fitness while also accumulating fatigue, so readiness should gate intensity. When recovery signals are low, Theron reduces load; when you are fresh, it progresses the plan. Athletes get guided workouts they can export to Apple Watch or as .FIT/.ZWO files, plus strength sessions and race-specific periodization—without hiring a coach to manually rewrite the calendar every time life intervenes.

Adaptive triathlon training means your workout schedule changes with your recovery instead of forcing a fixed calendar. Research on heart rate variability shows that day-to-day HRV shifts track autonomic readiness; for example, Vesterinen et al. (2016) reported that recreational runners whose moderate/high-intensity sessions were timed with morning HRV improved 3,000 m running performance, while a matched predefined-plan group did not show a significant gain over the same intensive block. Theron applies that principle by reading sleep and HRV from Apple Watch or Garmin data and automatically scaling swim, bike, and run intensity when recovery is low. That prevents the common failure mode of static PDF plans, which keep prescribing hard sessions after poor sleep or illness. The result is a safer progression toward race day: volume and intensity still periodize, but each session is filtered through your current readiness rather than yesterday’s printed schedule—so adaptive training is not marketing jargon, it is load management grounded in published sports science.

Probably, Yes! Theron integrates directly with Apple Watch, Garmin and Wahoo. And if you have a different device, we also connect with Strava or Apple Health, so we can still track your training progress.

Absolutely. Theron provides the workout structure (duration and intensity) in the form of a .FIT or .ZWO. You can manually import these workouts on platforms like Zwift, Wahoo or a treadmill, and as long as the data writes back to Theron, we will track your progress.

Not at all. Theron was built with beginners in mind. We use simple language, not complicated jargon. Our personalized training plans will gradually build your fitness safely, ensuring you don't do too much too soon.

Life happens! Unlike static PDF plans that make you feel guilty for missing a day, Theron instantly recalculates your future schedule. If you miss a session, the app adapts your plan to keep you on track without overloading you the next day.

Yes. You have full control over your weekly schedule. Theron builds the plan around your availability by looking at your daily availability and your sports preference.

Yes. Theron includes strength sessions in your plan, tailored to your lifting experience, available equipment, and focus areas, so you build durability alongside your swim, bike, and run fitness.

Your privacy is our priority. Theron processes your health data locally on your device wherever possible. We do not sell your personal health data to third parties. See our Privacy Policy.

The 30-day free trial gives you full access to Theron Unlimited. You can generate a custom race plan, use the personalized workout export features, and experience the daily adaptive adjustments. No features are locked during the trial.

Pricing follows the Apple App Store in your region (for example about €12.99 per month in the Eurozone or about $14.99 per month in the United States). The yearly plan is typically about half off versus paying monthly in the Eurozone. A human triathlon coach often runs €100–€300 per month—Theron is built to deliver adaptive, pro-level planning at a fraction of that cost. Open the Theron listing on the App Store to see the exact amount where you live.