Instrumented Tennis Racket to Train Proper Grip in Novice Tennis Players

This instrumented tennis racket is designed to help novice players maintain proper grip strength and reduce the risk of developing tennis elbow. Tennis elbow is a condition caused by repeatedly gripping the racket with excessive force which strains the muscles causing tears and inflammation. The racket features embedded force sensors to measure grip strength and provides real-time haptic feedback, signaling players to adjust their grip during training. A phone app connects to the racket and records grip strength for each swing session, reinforcing proper technique. Eight to ten miniature 12 mm motors were placed in the base of a Wilson tennis racket. When grip strength exceeded a set threshold (half of the player's maximum measured grip) a vibration alerted them to loosen their grip. Three force sensor strips were applied to bevels 2, 3, and 4, corresponding to the continental, eastern, and semi-western grips, respectively. These sensors transmitted data to an Arduino Nano 33 IoT, which controlled the haptic feedback and Bluetooth connection to the app. A pilot test with one participant showed that the average force applied was 9% for the eastern grip, 29% for the continental, and 31% for the semi-western (all based on maximum grip strength). The lower force on bevel 3 aligns with its wider, flatter surface, which provides less contact area than the angled bevels 2 and 4. Though tested on a single participant, the results support the potential of this device in guiding grip strength training. Future work will involve the beginners tennis class at Hope College to assess broader trends. The device currently focuses on dominant-hand swings (serve, forehand, volley), with potential expansion to two-handed backhands. This work demonstrates that an instrumented racket can effectively measure grip forces and may help novice players develop proper technique while reducing risk of injury.