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Terms of Service

Last updated: 27 August 2026

These terms are the agreement between you and Inertia Training ("the app", "we") for use of the app. By creating an account or using the app, you accept them. If you do not agree, please don't use the app. Your software license itself is Apple's Standard End User License Agreement; these terms cover everything specific to Inertia Training.

What Inertia Training is

Inertia Training is an independent companion app for intervals.icu. It reads the training data already in your intervals.icu account and presents it in a form designed for your phone. We are not affiliated with, endorsed by, or operated by intervals.icu, and intervals.icu is not responsible for this app.

You need your own intervals.icu account to use Inertia Training. Your use of that service is governed by its own terms, not these, and we have no control over it. If intervals.icu changes, restricts or withdraws access to its API, parts of this app may stop working.

Your account

You are responsible for keeping your password secure and for what happens under your account. Give accurate information when you sign up. You must be at least 13 years old to create an account.

Your intervals.icu API key and what it allows

When you connect your API key, you authorise the app to act on your behalf against your intervals.icu account. That includes writing, not only reading: the app can create, edit, move and delete planned workouts and calendar events, edit activity details such as name, notes, perceived exertion and how you felt, delete activities, and update your training zones. These changes happen on your live intervals.icu account and are visible in every other tool you use with it.

Every one of those actions is something you trigger yourself in the app. Still, they are real and in most cases immediate, so you are responsible for the changes you make through the app. You can revoke the key at any time from your intervals.icu settings.

Acceptable use

You agree not to:

• Use the app to access an intervals.icu account you are not authorised to use.
• Attempt to break, overload, probe or circumvent the app, our servers, or the rate limits of any service the app depends on.
• Reverse engineer, decompile, or attempt to extract source code or credentials.
• Resell, redistribute or offer the app as a service to others.
• Use the app for anything unlawful.

Not medical advice

Inertia Training is a training and fitness tool. It is not a medical device, and nothing in it is medical advice, diagnosis or treatment. Fitness, form, training load, zones, recovery and wellness figures shown in the app are estimates derived from your own recorded data and from published training models. They can be wrong, and they are not a judgement about your health.

Training carries physical risk. Decisions about how hard to train, when to rest, and whether to exercise at all are yours. Consult a qualified professional before starting or changing a training programme, and seek medical attention for any symptom that concerns you. Do not use this app as a reason to ignore how you feel.

Price

The app is currently free to use. If we introduce paid features in future, we will update these terms and make the price, billing period and renewal terms clear before you are charged. Nothing here obliges you to pay anything today.

Availability

We do not guarantee the app will be available without interruption or free of errors. The app depends on services we do not control, including intervals.icu, and it may be unavailable when they are. We may change, suspend or discontinue any part of the app.

Your data

How we handle your data is described in our Privacy Policy. Your training data belongs to you and lives in your intervals.icu account. Deleting your Inertia Training account removes your account and stored key from our systems and does not touch your intervals.icu account.

Ending your use

You can stop using the app at any time and delete your account from Profile → Delete Account. We may suspend or terminate an account that breaches these terms, or where we are required to by law.

No warranty

The app is provided "as is" and "as available", without warranties of any kind, whether express or implied, including any implied warranty of merchantability, fitness for a particular purpose, or non-infringement. We do not warrant that the data or calculations shown are accurate or complete.

Limitation of liability

To the fullest extent permitted by law, we are not liable for any indirect, incidental, special or consequential loss, nor for lost data, lost training records, missed sessions, lost profits, or injury arising from your use of the app. Nothing in these terms limits liability that cannot be limited by law, including liability for death or personal injury caused by negligence, or for fraud.

Changes to these terms

We may update these terms. When we do, we'll change the "Last updated" date above. Continuing to use the app after a change means you accept the updated terms.

Governing law

These terms are governed by the laws of Singapore, and the courts of Singapore have exclusive jurisdiction, without affecting any mandatory consumer rights you have where you live.

Contact

Questions about these terms? Email support@inertia.training.