Tri-Sea combines peer-reviewed sports science with AI-powered coaching to build your perfect triathlon training plan. Track fitness, manage fatigue, and peak on race day.
From your first sprint tri to Ironman — Tri-Sea adapts to your level, your schedule, and your goals.
Track your Chronic Training Load (CTL), Acute Training Load (ATL), and Training Stress Balance (TSB) using the proven Banister impulse-response model. Know exactly when you're fit, fatigued, or race-ready.
Generate periodized training plans powered by AI that adapt to your fitness, schedule, and race timeline. Rolling 2-week detail enrichment keeps sessions fresh.
Purpose-built for triathlon with sport-specific zones, workout types, and TSS calculations for each discipline.
Visual calendar with phase-colored weeks, session indicators, race day markers, and Apple Calendar sync for seamless scheduling.
Track fitness trends, zone distribution, heart rate decoupling, ramp rate, and estimated thresholds (FTP, CSS, threshold pace) over time.
Sync workouts, heart rate, HRV, sleep, and menstrual cycle data from Apple Health. Your training decisions backed by your real physiology.
Built-in science library with peer-reviewed citations. Every training recommendation is grounded in research you can read and verify.
Countdown to race day with CTL target tracking, taper optimization, and form status alerts. Peak at the right moment.
Choose from Ocean, Sunset, Forest, Midnight, or Classic themes. Full dark mode support across every view.
Tri-Sea doesn't guess. The training engine is built on established sports science models and verified research.
Fitness (CTL, τ=42d) and fatigue (ATL, τ=7d) impulse-response model for training load management. TSB = CTL − ATL predicts form and race readiness.
Based on Stöggl & Sperlich (2014): 80% low intensity + 20% high intensity produces greater VO2max improvements than threshold or high-volume models.
Gabbett (2017): keeping the acute:chronic workload ratio between 0.8–1.3 is the "sweet spot" for adaptation without excessive injury risk.
Schmitt et al. (2015): HRV-guided training produces equal or superior endurance gains while reducing overtraining risk compared to pre-planned approaches.
Mujika (2010): exponential taper with 40–60% volume reduction over 2–3 weeks while maintaining intensity yields 2–6% performance improvement.
Fullagar et al. (2015): sleeping less than 7 hours increases injury risk by ~51% and significantly impairs endurance performance and recovery.
Built with SwiftUI and SwiftData. Your training data syncs seamlessly via iCloud between your Mac and iPhone.
Full-featured desktop experience with NavigationSplitView sidebar, wide charts, and HSplitView detail panels. Designed for deep analysis sessions.
Optimized for iPhone with tab-based navigation, responsive layouts, and HealthKit sync for workouts, heart rate, HRV, and sleep data.
Tri-Sea is coming soon to the App Store for Mac and iPhone. Be the first to know when it launches.
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$14.99/mo
Have a question, found a bug, or want to request a feature? Reach out and we'll get back to you.