Fitness apps can process information locally, store it in a cloud account, or combine both approaches. The important question is not whether an app uses a server at all; it is which information leaves the device, why it leaves, and what choices the user has.
What Strenua Does on the Device
Strenua's workout engine runs locally. It uses versioned exercise and equipment data, your training profile, completed performance, planned set ranges, and your current readiness check-in to build a workout. Core planning, workout generation, logging, and history do not require a remote AI request.
This local design keeps the core training experience responsive and available when a gym has poor connectivity. It also reduces the amount of information that needs to be processed by external services.
What Uses Online Services
Strenua is not a zero-cloud product. The following optional or account-related features require connectivity:
- Sign in with Apple or Google through Firebase Authentication
- Firebase account sync, cloud backup, and restore
- RevenueCat subscription verification and entitlement management
- Apple App Store purchase and restore services
When a user signs in, selected profile, workout, personal-record, custom-exercise, template, and synchronization data can be stored in Cloud Firestore. HealthKit records are not included in that backup. Health restrictions remain on the device unless the user separately enables their cloud sync.
Why the Distinction Matters
"On-device" should describe where a particular calculation happens, not imply that an app has no network services. Strenua's training calculations happen locally, while clearly identified account, backup, and purchase functions use their respective providers.
The app does not sell personal information, use advertising SDKs, or track users across apps and websites. Users can stay signed out, decline HealthKit access, export local training data, manage Apple subscriptions directly, and delete a signed-in Strenua account and its Firestore backup.
Questions to Ask Any Fitness App
- Which features work without an account or connection?
- Which data types are uploaded, and for what purpose?
- Can cloud backup be avoided or deleted?
- Are health records separated from app-entered profile data?
- Does the app sell data or use it for cross-app tracking?
Those answers are more useful than a broad "local" or "cloud" label. Strenua documents its current behavior in the Privacy Policy and explains the workout flow in How It Works.