Our Philosophy

We're not another fitness app.

The world doesn't need another workout tracker. There are already great ones — Hevy for strength, Strava for cardio, Garmin and Apple Watch for data. They're excellent at what they do.

What's missing is the intelligence layer. The part that looks at your training history, understands exercise science, and creates a structured program that actually leads somewhere. That's what phase.fitness is.

We're an AI that creates programs for your favorite apps.

How we think about training

Programs, not workouts

A single workout in isolation is almost meaningless. What matters is how workouts connect into a progressive sequence — building volume, shifting intensity, managing fatigue, and peaking at the right time. This is periodization, and it's the foundation of everything we do.

Adaptation over prescription

No plan survives contact with reality. Your body responds differently than expected, life gets in the way, some exercises work better than others. phase.fitness reads your actual performance and adjusts — weekly workload updates, automatic deloads, RPE-based progression. The program evolves with you.

Data from everywhere, intelligence from us

Your training data lives in many places — Hevy logs your sets, Strava tracks your runs, your watch measures your heart rate, Intervals.icu aggregates your wellness. We pull all of this together and use it to make smarter decisions about your next training block.

The Ideal Workflow

Once a week, for 10 minutes

phase.fitness isn't meant to be open all day. The ideal usage is a weekly check-in where the AI reviews your progress and prepares your next training block.

Step 1

Import data

Sync your latest workouts from Hevy and Strava. Wellness data flows in automatically from Intervals.icu.

Step 2

AI reviews

The AI analyzes your performance, fatigue signals, HRV trends, and progress against your program goals.

Step 3

Update workload

Adjust next week's training with one click. The AI modifies volume, intensity, and exercise selection based on your recovery.

Step 4

Push & train

Sync updated routines to Hevy and cardio to Intervals.icu. Open your favorite app and train.

The rest of the week? Train in Hevy, run with your watch, live your life. phase.fitness works in the background — it's your training intelligence, not your daily workout app.

Your apps, AI-enabled

We don't replace your tools — we make them smarter. Through our integrations, every app in your training stack gets the benefit of AI-powered periodization.

phase.fitness
AI Training Intelligence
Strava
Import data
Intervals.icu
Cardio & wellness
Hevy
Strength sync
via Intervals.icu
Apple Watch
via Watchletic
Garmin
Connect
Suunto
Sports
COROS
Training Hub
Wahoo
SYSTM
Amazfit
Zepp

Device sync powered by Intervals.icu — a powerful open training platform that connects to all major sports watches and bike computers.

Strength

Routines sync to Hevy with sets, reps, load%, and RPE targets.

Cardio

Structured workouts push to Intervals.icu with intervals and HR zones.

Wearables

Via Intervals.icu: Garmin, Suunto, COROS, Apple Watch, Wahoo, Amazfit.

What we believe

Training should be structured, not random. Science-based periodization beats motivation every time.

AI should augment coaches, not replace them. We automate the programming — you bring the effort.

Your data belongs in the apps you already use. We're the brain, not the tracker.

Recovery is not optional. Deloads, fatigue management, and wellness monitoring are first-class features.

Transparency matters. We clearly attribute features to the platforms that power them. Intervals.icu connects to your watch — we just send it smart workouts.

Start training with purpose

Create your first AI-powered, periodized training program in minutes.