Responsible for data processing in connection with this website and the TennisFlow App:
One Tree Hill GmbH
Represented by the Managing Director: Werner Märkl
Oppenheimer Landstr. 70
60596 Frankfurt am Main
Germany
Contact:
Email: info@tennisflow.app
Phone: +49 (0)1567 8302216
The TennisFlow App uses modern AI technologies (on-device machine learning) to analyse tennis movements.
Purpose: The app requires access to the camera and your photo gallery to create and save sports biomechanical recordings.
Local Processing (On-Device): Video analysis is performed entirely locally on your mobile device. No video files, individual frames or audio data are transmitted to our servers or the servers of third parties.
Storage: Recorded videos remain in the app's sandbox on your device and are deleted as soon as you remove them within the app or uninstall the app.
To improve our algorithms and provide progress statistics, we only transmit anonymised mathematical data points (e.g. joint angles, stroke timestamps).
This data does not allow any conclusions to be drawn about your identity or appearance.
The legal basis is our legitimate interest in optimising app functionality (Art. 6(1)(f) GDPR).
When setting up your user account or within the profile settings, we collect data that is technically required for a personalised analysis of your movement patterns:
Purpose: This data is required to correctly calibrate the AI-powered motion analysis to your individual biomechanics.
Legal Basis: Art. 6(1)(b) GDPR (performance of contract).
To enable long-term improvement of your game, the app stores the results of the technique analyses performed.
Data processed: We store metadata from your video analyses (e.g. joint angles, hit-point statistics, movement scores) as well as the time of the analysis.
Purpose: The data is stored to display a graphical overview of your technical progress over time and to provide targeted training recommendations based on your development.
Legal Basis: Art. 6(1)(b) GDPR (performance of contract).
We store your data only for as long as it is necessary to provide our services or until you delete your user account.
Immediate deletion: When you delete your account within the app or through our support system, all personal data associated with your user account will be deleted immediately and irreversibly from our servers. This includes in particular profile and master data, analysis results and progress history, uploaded content, and support messages.
Legal basis: Art. 6(1)(b) GDPR (performance of contract) during use; after deletion of your account, Art. 17 GDPR (right to erasure).
Exceptions: Data that we are required to retain under statutory retention obligations (e.g. commercial or tax law) is excluded from deletion and will be deleted after the respective retention period has expired.
Note: Once deleted, data cannot be restored. Videos and analysis results stored locally on your device are not automatically removed by account deletion; they remain on your device until you delete them within the app or uninstall the app (see section 2 A).
To provide the features of the TennisFlow App, the app accesses the following system functions on your device:
To provide our services, ensure secure data management and AI-powered analysis, we use the infrastructure of external service providers.
We use the Firebase development platform provided by Google Ireland Limited (Gordon House, Barrow Street, Dublin 4, Ireland).
Server Location: We have configured the setup so that the storage of your data (Cloud Storage and Database) as well as the execution of computing logic (Cloud Functions) takes place exclusively in the Google Cloud region europe-west3 (Frankfurt, Germany).
Purpose:
Data: Pseudonymised analysis parameters (e.g. joint angles, timestamps), device IDs and technical logs.
Legal Basis: Art. 6(1)(f) GDPR (legitimate interest in a secure, high-performance infrastructure hosted in Germany).
For in-depth biomechanical evaluation of movement data, we use Google's Gemini API interface.
Purpose: The coordinates generated locally on your device are transmitted to the interface to create automated training recommendations and error analyses using artificial intelligence.
Privacy Guarantee: Only abstract mathematical data points are transmitted. Image or video material is never transmitted to the Gemini API at any time.
Legal Basis: Art. 6(1)(b) GDPR (performance of pre-contractual measures or contract fulfilment, as AI analysis is an integral part of the app's functionality).
Although we have chosen Frankfurt as the storage location, Google is a company headquartered in the USA. It therefore cannot be entirely ruled out that metadata or maintenance information may be transferred to Google LLC in the USA. Google is certified under the EU-US Data Privacy Framework, which guarantees an adequate level of data protection.
Our website is operated by an external hosting provider. Server log files (IP address, timestamp) are automatically recorded there to ensure secure operation (Art. 6(1)(f) GDPR).
Under the applicable legal provisions (GDPR), you have the right at any time to:
Please contact us informally at: support@tennisflow.app