Terms and Conditions

Last updated: 3 October 2026

1. Who we are

These Terms govern your use of maxtrubemd.com, zones.maxtrubemd.com and assessment.maxtrubemd.com, and the services offered through them.

Maxim Trube
Hochdahler Markt 2
40699 Erkrath
Germany

Email: endurancemaxtrube@mailbox.org

Sole trader under German law. Full details are in our Impressum.

2. What we offer

• Library access — articles, training guides, illustrations and downloadable PDFs on endurance performance, nutrition and health, available as a yearly subscription or a one-time Lifetime purchase
• Zones — the Training Zone Calculator, a yearly subscription

The endurance quiz at assessment.maxtrubemd.com is free and requires no account.

3. Who can use our services

Our services are for people aged 18 or over. By registering or purchasing, you confirm that you meet this requirement.

4. How a contract is formed

The presentation of our services on our websites is an invitation to make an offer, not a binding offer.

You make an offer by completing the order process and clicking the order button. Before you do, we show you the essential features of the service, the total price, the contract term and the cancellation terms.

The contract is formed when we confirm it. We will send you confirmation by email, including these Terms and the withdrawal notice, on a durable medium.

5. Prices and payment

Prices are shown on the relevant product page.

We do not charge VAT. As a small business under § 19 UStG, we do not show VAT separately on our invoices (Kleinunternehmerregelung).

Payment is handled by Stripe and is due in advance for each billing period. Payment is completed on Stripe's own platform.

6. The library

What you get

The library contains articles, training guides, illustrations and downloadable PDF documents on endurance performance, nutrition and health.

The library is still being built. When you subscribe or purchase, you get immediate access to everything published so far, and to everything added during your access period. We expect the library to be complete by 1 January 2027. The contents available today are listed on the pricing page.

All library content can be downloaded.

Yearly access

The initial term is twelve months, paid in advance.

You may cancel with one month's notice to the end of that term. If you do not, the contract continues for an indefinite period. You may then cancel at any time with one month's notice.

We continue to bill annually. If you cancel during a period you have already paid for, we refund the unused months pro rata, calculated from the date your cancellation takes effect.

Lifetime access

A one-time payment for continued access to the library for as long as we operate it.

If we ever discontinue the library:

• We will give you at least 12 months' notice, during which you can download the entire library and keep it permanently.
• If we discontinue within 24 months of your purchase, we will also refund you pro rata, calculated against a ten-year reference period. For example, if we discontinue eight months after you buy, we refund 112/120 of what you paid.

After the notice period, the material you have downloaded remains yours to keep.

7. Zones

Zones calculates individual training zones from time-trial data you enter, and stores your test history so you can follow your progression over time.

What Zones is

You enter the results of three to five maximal efforts. Zones fits a two-parameter critical speed or power model to that data and returns four values — your critical speed or power, first threshold, and speed at maximal oxygen uptake — together with three training zones.

Zones also includes educational material on how endurance training is generally structured. This is general information about training principles. It is not a plan, and it is not instructions for you specifically.

What Zones is not

Zones is a training tool. It is not a medical device. It does not diagnose, treat, monitor, prevent or predict any disease or condition, and it is not intended to.

It does not replace laboratory testing. The values it returns are estimates of quantities that lactate testing or a VO₂ max test would measure directly. They are useful, and they are not the same thing.

It does not replace medical, sports-medical or coaching advice. Zones gives you numbers. What you do with them is your decision — and one you may want to take with a coach or a doctor.

The limits of the calculation

The model is only as good as the efforts behind it. If your trials were poorly paced, run on an unsuitable course, cut short, or performed when you were ill, tired or undertrained, the values will be wrong — and Zones cannot tell that they are.

The reference tables used to place your results in a performance category are based on population data. Individual physiology varies considerably, and yours may sit outside what the model predicts.

Your zones are not fixed. Illness, fatigue, heat, altitude, poor sleep, medication and stress all change what your body can do on a given day, sometimes substantially. Values that were right last month may not be right today.

How you feel takes priority over what the screen says. If a session at a calculated intensity feels wrong, it is wrong. Stop or ease off.

Testing carries real risk

The efforts Zones asks you to perform are maximal or near-maximal. See section 12 for what that means and what we recommend before you do them.

Subscription

The initial term is twelve months, paid in advance.

You may cancel with one month's notice to the end of that term. If you do not, the contract continues for an indefinite period, and you may then cancel at any time with one month's notice.

We continue to bill annually. If you cancel during a period you have already paid for, we refund the unused months pro rata, calculated from the date your cancellation takes effect.

Your data when your subscription ends

When your subscription ends you lose access to Zones, but your test history is not deleted. It stays with your account, so that if you resubscribe later your progression is still there.

Export your data before your access closes if you want a copy on your own computer. Once access closes you can no longer export from inside Zones. You can still ask us for a copy at any time by email and we will send it within one month.

Deleting your account

You can delete your account at any time. Deletion is immediate and permanent. Your profile, your sign-in data and your entire test history are removed straight away and cannot be recovered. We cannot restore them for you afterwards.

Invoices and payment records are the one exception: German tax and commercial law requires us to keep them, so they are retained for the statutory period independently of your account.

8. Your right of withdrawal

If you are a consumer, you have the right to withdraw from this contract within 14 days without giving any reason.

The withdrawal period is 14 days from the day on which the contract was concluded.

To exercise your right of withdrawal, you must inform us by means of a clear declaration that you are withdrawing from the contract:

Maxim Trube
Hochdahler Markt 2
40699 Erkrath
Germany
Email: endurancemaxtrube@mailbox.org
Telephone: +49 151 12740684

You may use the model withdrawal form set out below, but you are not obliged to. To meet the deadline it is sufficient that you send your declaration before the withdrawal period has expired.

We do not ask you to waive this right, and we do not treat it as lost when you start using the service. You have the full 14 days regardless of whether you have accessed the library or run a test in Zones.

Effects of withdrawal

If you withdraw from this contract, we will reimburse all payments we have received from you without undue delay and in any event no later than 14 days from the day on which we receive notice of your withdrawal. We will use the same means of payment that you used for the original transaction, unless expressly agreed otherwise, and you will not be charged any fees for the reimbursement.

Model withdrawal form

(Complete and return this form only if you wish to withdraw from the contract.)

To: Maxim Trube, Hochdahler Markt 2, 40699 Erkrath, Germany, endurancemaxtrube@mailbox.org

I/We (*) hereby give notice that I/We (*) withdraw from my/our (*) contract for the provision of the following service:

- Ordered on (*) / received on (*)
- Name of the consumer(s)
- Address of the consumer(s)
- Signature of the consumer(s) (only if this form is notified on paper)
- Date

(*) Delete as appropriate.

9. Cancelling your subscription

You can cancel at any time by writing to endurancemaxtrube@mailbox.org.

You keep full access until your cancellation takes effect.

10. Your account

You need an account to use the library and Zones. Keep your login details confidential and tell us promptly if you think someone else has used your account. Accounts are personal and may not be shared.

You are responsible for the accuracy of the data you enter into Zones. The value of the results depends directly on the quality of the tests behind them.

11. Content and intellectual property

The content of our websites — articles, training guides, illustrations, images and text — belongs to us and is protected by copyright.

Your purchase gives you a personal, non-transferable right to use the content for your own training. You may not republish it, redistribute it or make it publicly available.

Your statutory rights, including quotation and private copying, are unaffected.

Files you download during your access period remain yours to keep.

The test data you enter into Zones, and the values calculated from it, remain yours.

12. Health and safety

Endurance training and maximal efforts carry real risks, including injury and, in rare cases, cardiac events.

Before you start a new training programme, significantly increase your training, or perform maximal or near-maximal efforts, you should be assessed by a qualified healthcare professional. This applies particularly if you have any existing medical condition, experience symptoms during exercise, are returning after a long break, or are over 35.

Stop immediately if you experience chest pain, unusual breathlessness, dizziness, faintness or any other concerning symptom, and seek medical advice.

You decide whether and how to apply our guidance to your own training. Take your body seriously and train within your limits.

13. Our liability

We are liable without limit for intent and gross negligence, and for injury to life, body or health.

For ordinary negligence, we are liable only where we breach an obligation that is essential to performing the contract and on which you may reasonably rely. In that case our liability is limited to foreseeable damage typical for this type of contract.

Liability under the Product Liability Act is unaffected.

14. Governing law

German law applies, excluding the UN Convention on Contracts for the International Sale of Goods.

If you live in another country, the mandatory consumer protection rules of that country continue to apply to you.

15. Language

These Terms are published in English, and the English version governs your contract.

16. Contact

Maxim Trube
Hochdahler Markt 2, 40699 Erkrath, Germany
endurancemaxtrube@mailbox.org

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