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Terms of Use

Terms of Use

Effective Date: May 2, 2026

1. Acceptance of Terms

SinewFit LLC ("SinewFit," "we," "us," "our"), a New Jersey Limited Liability Company, operates the website sinewfit.ai, the SinewFit iOS application, and the companion SinewFit Apple Watch application (collectively, "the Service"). By accessing or using the Service, you agree to be bound by these Terms of Use ("Terms"). If you do not agree to these Terms, you may not access or use the Service. Your continued use of the Service constitutes your acceptance of any updates or modifications to these Terms.

1A. Age Requirement

You must be at least 18 years of age to create an account or use the Service. By creating an account, you represent and warrant that you are at least 18 years old. SinewFit does not knowingly provide services to individuals under the age of 18. If we learn that a user is under 18, we will terminate their account and delete their data promptly.

2. Description of Service

SinewFit is a fitness application available on the web, on iOS, and on Apple Watch. It provides AI-generated workout plans, exercise recommendations, workout logging tools, and an in-app AI Coach that responds to fitness questions. The Service uses artificial intelligence to create personalized fitness programs based on user-provided information such as fitness goals, experience level, available equipment, physical metrics, and prior workout history.

The iOS app may integrate with Apple Health (HealthKit) to read heart-rate samples captured by your paired Apple Watch during a SinewFit workout and to write workout summaries back to Apple Health. The Apple Watch app supports starting and logging strength workouts on the watch and capturing heart-rate data during a session. HealthKit integration is optional and requires your explicit permission via the iOS Health permission prompts.

The Service is intended for informational and educational purposes only. SinewFit does not provide medical advice, diagnosis, or treatment of any kind.

3. Medical Disclaimer

The fitness information provided by SinewFit is for educational and informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition or before starting any exercise program.

SinewFit does not provide medical advice. The AI-generated workout plans and exercise recommendations are created algorithmically and have not been reviewed or approved by a medical professional. You should consult a physician before beginning any exercise program, particularly if you have any pre-existing health conditions, injuries, or concerns.

You acknowledge and agree that you assume all risk of injury, disability, or death that may result from following any workout plans, exercise recommendations, or other content provided by the Service. SinewFit and its creators, operators, and affiliates shall not be held liable for any injuries, health complications, or damages sustained while following AI-generated workout plans or exercise recommendations.

If you experience any pain, discomfort, or adverse physical symptoms during exercise, you should immediately stop and seek medical attention.

Wearable heart-rate data is not medical-grade. Heart-rate readings, time-in-zone summaries, and any recovery or effort metrics that SinewFit displays are derived from consumer-grade sensors on devices such as Apple Watch. They are intended only for general fitness tracking and self-awareness. They are not a substitute for medical heart-rate monitoring, electrocardiogram (ECG), or any other diagnostic tool, and must not be used to diagnose, monitor, or manage any heart condition. If you have any cardiovascular concern, follow the advice of a qualified medical professional rather than the readings shown in this app.

4. Assumption of Risk

You acknowledge that physical exercise and fitness activities involve inherent risks, including but not limited to: physical injury, muscle strains, sprains, fractures, joint damage, cardiovascular events, disability, and in extreme cases, death. These risks may result from your own actions, the actions of others, equipment malfunction, or the conditions of the exercise environment.

By using the Service, you voluntarily assume all such risks, whether known or unknown, even if arising from the negligence of SinewFit or its creators, and you agree to accept full responsibility for any injury, illness, damage, loss, or cost resulting from your participation in any exercise or fitness program recommended by the Service.

5. Limitation of Liability

To the maximum extent permitted by applicable law, SinewFit, its creators, operators, affiliates, officers, directors, employees, agents, and licensors shall not be liable for any direct, indirect, incidental, consequential, special, exemplary, or punitive damages arising out of or in connection with your use of, or inability to use, the Service.

This limitation applies to all claims, whether based on warranty, contract, tort (including negligence), strict liability, or any other legal theory, and whether or not SinewFit has been advised of the possibility of such damages. This includes, without limitation, damages for personal injury, pain and suffering, emotional distress, loss of revenue or profits, loss of data, or any other damages.

In no event shall the total aggregate liability of SinewFit exceed the amounts paid by you, if any, for accessing the Service during the twelve (12) months preceding the claim.

6. Indemnification

You agree to indemnify, defend, and hold harmless SinewFit and its creators, operators, affiliates, officers, directors, employees, and agents from and against any and all claims, damages, obligations, losses, liabilities, costs, or expenses (including but not limited to attorney's fees) arising from: (a) your use of the Service; (b) your violation of these Terms; (c) your violation of any rights of a third party; or (d) any injury or harm you sustain as a result of following workout plans, exercise recommendations, or other content provided by the Service.

7. User Accounts and Security

To use certain features of the Service, you must create an account. You are responsible for maintaining the confidentiality of your account credentials and for all activities that occur under your account. You agree to provide accurate, current, and complete information during registration and to keep your account information updated.

You must immediately notify SinewFit of any unauthorized use of your account or any other breach of security. SinewFit shall not be liable for any loss or damage arising from your failure to safeguard your account credentials.

8. Acceptable Use

You agree not to:

  • Share your account credentials with any other person or allow others to access your account
  • Create multiple accounts for the same individual
  • Scrape, crawl, or use automated means to access or extract data from the Service
  • Reverse engineer, decompile, disassemble, or attempt to derive the source code of the Service
  • Use the Service to develop a competing product or service
  • Interfere with or disrupt the integrity or performance of the Service
  • Attempt to gain unauthorized access to any systems or networks connected to the Service
  • Use the Service for any unlawful or fraudulent purpose

9. AI-Generated Content and AI Coach

The workout plans, exercise recommendations, day redesigns, daily insights, recap summaries, activity classifications, and AI Coach chat replies provided by the Service are generated algorithmically using artificial intelligence (currently Anthropic's Claude family of models). While we strive for accuracy and safety, AI-generated content may contain errors, inaccuracies, hallucinations, or recommendations that may not be appropriate for your specific circumstances.

You should always use your own judgment when following AI-generated workout plans or AI Coach advice. If an exercise feels unsafe, causes pain, or seems inappropriate for your fitness level, you should skip it or substitute an alternative. The AI Coach is not a certified personal trainer, medical professional, registered dietitian, or therapist, and its replies must not be relied on for medical, nutritional, mental health, or emergency advice. The Service is a tool to assist your fitness journey, not a replacement for professional guidance.

By using the AI Coach, you acknowledge that the messages you send are transmitted to a third-party AI provider (currently Anthropic) for the sole purpose of generating a reply. You agree not to send the AI Coach (a) information about other people without their consent, (b) protected health information you would not want stored, (c) confidential or proprietary information belonging to a third party, or (d) content intended to elicit unsafe or unlawful output.

10. Beta Features and Early Access

SinewFit may offer beta features, early access programs, or pre-release functionality ("Beta Features"). Beta Features are provided "as is" and "as available" without warranties of any kind. We make no guarantees regarding the availability, reliability, or continuity of Beta Features. SinewFit reserves the right to modify, suspend, or discontinue any Beta Feature at any time without notice.

Feedback, suggestions, or ideas you provide regarding Beta Features may be used by SinewFit to improve the Service without any obligation or compensation to you. Your participation in any beta program is voluntary and does not entitle you to continued access to any specific feature.

11. Subscription and Billing

SinewFit may offer paid subscription plans ("Pro" or similar tiers) that provide access to additional features. By subscribing to a paid plan, you agree to the following:

Free Trials

If offered, free trials provide temporary access to paid features. You must provide a valid payment method to start a free trial. Unless you cancel before the trial period ends, your payment method will be automatically charged at the applicable subscription rate. Trial eligibility is limited to one trial per user.

Auto-Renewal

Paid subscriptions automatically renew at the end of each billing cycle (monthly or annually) unless you cancel before the renewal date. The renewal charge will be at the then-current subscription rate.

Cancellation

You may cancel your subscription at any time through your account settings or by contacting support@sinewfit.ai. Cancellation takes effect at the end of the current billing period. You will retain access to paid features until the end of the period you have already paid for. No partial refunds are provided for unused portions of a billing period.

Price Changes

SinewFit reserves the right to change subscription pricing at any time. We will provide at least 30 days' notice of any price increase. Your continued subscription after the price change takes effect constitutes acceptance of the new price. Users on promotional or founding member pricing will not be affected by general price increases for the duration specified at the time of their enrollment.

Payment Processing

Payments are processed by Stripe, Inc. Your payment information is transmitted directly to Stripe and is not stored on SinewFit's servers. Stripe's handling of your payment data is governed by their privacy policy and terms of service.

12. Intellectual Property

All content, features, and functionality of the Service, including but not limited to text, graphics, logos, software, and the AI algorithms used to generate workout plans, are the exclusive property of SinewFit LLC or its licensors and are protected by copyright, trademark, and other intellectual property laws.

You retain ownership of any personal data and information you provide to the Service. By using the Service, you grant SinewFit a limited license to use your data solely for the purpose of providing and improving the Service, as described in our Privacy Policy.

13. Termination

SinewFit reserves the right to suspend or terminate your account and access to the Service at any time, with or without cause, and with or without notice. Reasons for termination may include, but are not limited to, violations of these Terms, abusive behavior, or extended periods of inactivity.

You may terminate your account at any time by contacting us at the email address listed below. Upon termination, your right to use the Service will immediately cease, and you may request deletion of your data in accordance with our Privacy Policy.

14. Modifications to Terms

SinewFit reserves the right to modify these Terms at any time. We will notify users of material changes by updating the effective date at the top of this page. Your continued use of the Service after any such changes constitutes your acceptance of the modified Terms. We encourage you to review these Terms periodically.

15. Governing Law

These Terms shall be governed by and construed in accordance with the laws of the State of New Jersey, United States, without regard to its conflict of law provisions. SinewFit LLC is registered in the State of New Jersey. Any legal action or proceeding arising under these Terms shall be brought exclusively in the courts located in the State of New Jersey, and you hereby consent to the personal jurisdiction and venue of such courts.

16. Apple App Store and Apple Watch

The following terms apply to the SinewFit iOS application and the SinewFit Apple Watch application as obtained through Apple's App Store or TestFlight (the "Apple-Distributed Software") and supplement the rest of these Terms. In the event of conflict, the provisions of this Section 16 govern with respect to the Apple-Distributed Software only.

  • Acknowledgement. These Terms are concluded between you and SinewFit only, not with Apple, Inc. ("Apple"). SinewFit, not Apple, is solely responsible for the Apple-Distributed Software and its content.
  • Scope of license. The license granted to you for the Apple-Distributed Software is a limited, non-transferable license to use it on any Apple-branded products that you own or control, as permitted by the App Store Usage Rules in Apple's media-services terms.
  • Maintenance and support. SinewFit is solely responsible for providing any maintenance and support services with respect to the Apple-Distributed Software. Apple has no obligation whatsoever to furnish any maintenance and support services in connection with the Apple-Distributed Software.
  • Warranty. SinewFit is solely responsible for any product warranties, whether express or implied by law, to the extent not effectively disclaimed. In the event of any failure of the Apple-Distributed Software to conform to any applicable warranty, you may notify Apple, and Apple will refund the purchase price (if any) for the Apple-Distributed Software to you. To the maximum extent permitted by applicable law, Apple will have no other warranty obligation whatsoever with respect to the Apple-Distributed Software, and any other claims, losses, liabilities, damages, costs, or expenses attributable to any failure to conform to any warranty will be SinewFit's sole responsibility.
  • Product claims. SinewFit, not Apple, is responsible for addressing any claims by you or any third party relating to the Apple-Distributed Software or your possession and/or use of it, including but not limited to: (i) product-liability claims; (ii) any claim that the Apple-Distributed Software fails to conform to any applicable legal or regulatory requirement; and (iii) claims arising under consumer-protection, privacy, or similar legislation, including in connection with the Apple-Distributed Software's use of HealthKit.
  • Intellectual property. In the event of any third-party claim that the Apple-Distributed Software or your possession and use of it infringes that third party's intellectual property rights, SinewFit, not Apple, will be solely responsible for the investigation, defense, settlement, and discharge of any such intellectual-property infringement claim.
  • Legal compliance. You represent and warrant that (i) you are not located in a country subject to a U.S. Government embargo, or that has been designated by the U.S. Government as a "terrorist supporting" country; and (ii) you are not listed on any U.S. Government list of prohibited or restricted parties.
  • Third-party beneficiary. You and SinewFit acknowledge and agree that Apple, and Apple's subsidiaries, are third-party beneficiaries of these Terms, and that, upon your acceptance of these Terms, Apple will have the right (and will be deemed to have accepted the right) to enforce these Terms against you as a third-party beneficiary.
  • HealthKit. Your use of the Apple-Distributed Software with Apple HealthKit is also governed by Apple's HealthKit terms and your separate consent given via the iOS Health permission prompts. You may revoke any HealthKit permission at any time in Settings → Health → Data Access & Devices → SinewFit.

17. Contact Information

If you have any questions about these Terms of Use, please contact us at:

support@sinewfit.ai