Last updated: May 5, 2026
These terms govern your use of the Four by Four app (“the app”). By downloading or using the app, you agree to these terms.
Four by Four is a workout coaching app that guides you through the Norwegian 4×4 interval protocol using real-time heart rate data from Apple Watch. The app is provided “as is” without warranty of any kind.
The app is not a medical device and does not provide medical advice. Heart rate zones are estimates based on age-predicted formulas. Consult a physician before beginning any interval training program, especially if you have a history of cardiovascular disease.
The app reads heart rate data from Apple Watch via HealthKit and stores workout data locally on your device. No data is transmitted to external servers. See our Privacy Policy for full details.
You agree to use the app only for personal fitness purposes. You may not reverse-engineer, redistribute, or resell the app or its content.
All content, design, and code in the app are owned by Four by Four. Coach Norse audio coaching content is proprietary and may not be extracted or redistributed.
To the maximum extent permitted by law, Four by Four shall not be liable for any injury, health event, or damages arising from use of the app. You use the app at your own risk.
We may update or discontinue the app at any time. Deleting the app terminates these terms.
We may revise these terms at any time. The updated version will be posted at this URL with a new date. Continued use constitutes acceptance.
These terms are governed by the laws of the United States and the State of California, without regard to conflict of law principles.