• TennisTension is the FIRST WORKING mobile app that instantly measures the MOMENTOUS string tension of a tennis racquet with extreme consistency and accuracy (the error is less than 0.2 kg). Tracks the TENSION LOSS of the racquet's string all the time from the moment the racquet is strung. It records and analyzes the ringing sound heard from the strings when they are hit anywhere with any stiff object (pen, pencil, another racquet, fingernails, etc.).
• Systematically tested with different racquets and strings by players at a different level of play - from beginners to ATP professionals.
• At ATP Sofia 2019 on January, 3 from the seeded players tested, approved and gave recommendations for improvements, which we implemented: string pattern, hybrid stringing, string opening size influence, noise disruptions.
• The error of the measurements will be less than 0.2 kg If the user defines accurately all parameters of the racquet, string, and stringer/stringing machine.
• Parameters to preset: head size; string pattern; main and cross string thicknesses and types; string opening size; stringer/stringing machine type. If some of them are not defined, the app will use the average default values or the last values the user put in.
The "Calibration" can be used to cope SIMULTANEOUSLY and COMPLETELY with ALL specific characteristics of your PERSONAL racquet and string model. Use a TRUSTED stringer for the Calibration and read the provided instructions.

Instructions for use

- For best results use the app in places with less noise!
- The user has to learn how to produce the proper ringing sound CLOSE (2 to 10 cm) and IN FRONT of the phone microphone. Find the microphone which uses single, very small hole either at the TOP or at the BOTTOM of the phone.
- REMOVE the dampener - if you have.
- Tap the racquet strings VERY GENTLY ANYWHERE several times every 1 or 2 sec. with ANY STIFF object. KEEP the resonating RINGING strings CLOSE (2 to 10 cm) and IN FRONT OF the phone microphone. The best way is with a pen or pencil, or use another racquet, fingernails, etc. It is shown well in the YouTube video https://youtu.be/PNTyjG7jr98 provided for TennisTension mobile app, Google Play Store or on www.tennistension.app
- To receive the exact momentous string tension, define all the necessary racquet and string parameters. If you don't know some of them, default average values are taken for the calculations or the last values that the user put it in.
- TennisTension measures the average tension between main and cross strings of the racquet. For example, if a racquet is strung 25/24 kg, the measurement result will be 24.5 kg.
- String tensions of hybrid strings could be measured as well. In this case, define the parameters of both main and cross strings.
- The error of the measurement result is less than 0.2 kg when the accurate racquet, string, and stringer/stringing machine parameters are set.
- A Calibration for the app is provided in the case you want to cope COMPLETELY and SIMULTANEOUSLY with ALL specific characteristics of your PERSONAL racquet and string model. In this case, use a TRUSTED stringer.