One plan for swim, bike, run and strength that rebuilds around your week and eases off when your body needs it. No coach required.
Start free for 30 days
One plan across four sports, rebuilt around your week, and paced so you keep building without overdoing it.
Six in ten self-coached triathletes get hurt training for a race, usually from doing too much, too soon. Theron watches how fast your training is building and eases off in time.
Work ran late. Kid got sick. The week rebuilds itself around it. No catching up, no starting over.
Swim, bike, run and strength balanced together, so you are not overcooking one and neglecting another.
First sprint or fifth Ironman, same coach. One Theron athlete went from beginner to finishing a 70.3 in eight months.
Theron connects your wearable data to a smarter plan.
Every single day.
Tracks how fast your training is building week to week, the same way a coach watches an athlete, and pulls back before you tip into overtraining.
A plain-language read on every session, and what it means for tomorrow.
Structured sessions matched to your experience and the equipment you actually have.
Watches your cumulative load and flags when you are heading somewhere you should not.
As you get fitter, your training zones update themselves. No retesting, no manual entry.
Eases you down in the final weeks so you hit the start line rested and ready.
Join thousands of triathletes who trained smarter and crossed the finish line stronger.
"As a beginner Theron made triathlon training feel manageable. The app plans around my busy schedule and keeps me from overdoing it. Went from zero to finishing a 70.3 in 8 months!"
"Apple Watch integration works perfectly. Theron takes my training data, rebuilds my plan each week, and I've cut 11 minutes off my Olympic-distance time in one season. Absolutely worth it."
"A training app that uses my data to adapt its trainings on swimming, running and cycling! Did 2 triathlons so far, but this is helping me to become so much faster and better! Can’t go without!"
"The Apple Watch integration is seamless. Theron automatically adjusts workouts based on my sleep and HRV. A big change compared to my previous way of training. My times have dropped noticeably."
"The adaptive planning is a game-changer. Load adjusts automatically based on recovery, which feels really good. My Garmin data finally means something to me."
"I've tried other apps but Theron's focus on real-time health data makes it stand out. It's like having a personal coach, but less of a hassle and with the data to back it up."
"As a beginner Theron made triathlon training feel manageable. The app plans around my busy schedule and keeps me from overdoing it. Went from zero to finishing a 70.3 in 8 months!"
"Apple Watch integration works perfectly. Theron takes my training data, rebuilds my plan each week, and I've cut 11 minutes off my Olympic-distance time in one season. Absolutely worth it."
"A training app that uses my data to adapt its trainings on swimming, running and cycling! Did 2 triathlons so far, but this is helping me to become so much faster and better! Can’t go without!"
"The Apple Watch integration is seamless. Theron automatically adjusts workouts based on my sleep and HRV. A big change compared to my previous way of training. My times have dropped noticeably."
"The adaptive planning is a game-changer. Load adjusts automatically based on recovery, which feels really good. My Garmin data finally means something to me."
"I've tried other apps but Theron's focus on real-time health data makes it stand out. It's like having a personal coach, but less of a hassle and with the data to back it up."
Theron integrates with your favorite Platforms and Devices, including Apple Health, Apple Watch, Garmin, COROS, Google Health, Rouvy, Strava and Wahoo.
Peak on Race Day, Build Base & Endurance, or Stay Race-Ready. Whether you're training for your first Sprint or a Full Distance Ironman, Theron builds the plan around your goal.
Try Theron 30 Days for free
A human triathlon coach typically costs €100-€300 per month. Theron delivers adaptive coaching at a fraction of that.
$69.90 billed annually
Save vs monthly
Flexible, cancel anytime
Free calculators to sharpen your race strategy. No sign-up required.
Search 4,000+ triathlon races worldwide for your level and location
Calculate your cycling power-to-weight ratio
Plan your run, bike, or swim splits for race day
Find your Critical Swim Speed for structured swim training
Plan carbs, hydration, and electrolytes for race day
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, COROS, Google Health, 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, Garmin, COROS, Rouvy, 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.
No. Theron is built for your first race as much as your fifth. Plain language, gradual progression, and a plan that holds you back before you overdo it. You do not need to already know how to coach yourself.
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.
Yes. Theron integrates with Apple Health, Apple Watch, Garmin, COROS, Google Health, Wahoo, Strava, and Rouvy. Connect the sources you already use and Theron will track your training progress and adapt your plan.
Yes. Connect Rouvy to push structured bike workouts and sync indoor rides back to Theron. For Zwift and other platforms, Theron provides workout structure as .FIT or .ZWO files you can import manually, and as long as the completed data writes back to Theron, we track your progress.
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. Follow each session in the in-app workout player, exercise by exercise, with form notes, explainer videos, and a rest timer, so you build durability alongside your swim, bike, and run fitness.
Your privacy is our priority. Wearable, Apple Health, and Health Connect metrics you authorize are stored on Theron servers in the EU/EEA so we can build your plan. We do not sell your personal health data. 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 App Store or Google Play in your region (for example about €12.99 per month in the Eurozone or about $14.99 per month in the United States, with a yearly plan that is typically about half off versus paying monthly). A 30-day Unlimited trial is included. 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 or Google Play to see the exact amount where you live.
Or email us directly at: hello@theron.app
Scan this QR code with your iPhone to download Theron from the App Store
Or open in browser
