Mechanism of Shoulder Wiitis with Wii Tennis—A Biomechanical & EMG Analysis

Objective. To identify the differences in shoulder biomechanics and muscle activation patterns in recreational tennis players and non-players during forehand swing using Wii controller vs. regular racquet. Background. Since the launch of Nintendo’s Wii Gaming Console in 2006, numerous cases related to musculoskeletal injuries known as “Wiiitis” have been reported in the literature or seen in clinical practice, particularly in the recreational tennis players. With a better understanding of the difference in swinging Wii controller vs. regular tennis racquet, we may be able to identify the potential mechanism of Wii-tis and develop a prevention plan for Wii users. Methods. Ten mid-age recreational tennis players and 10 non-players will be recruited. Upper extremity biomechanical characteristics such as shoulder and elbow joint angular velocity and torque, as well as the limb velocity and acceleration during flat forehand swing, will be captured using a Functional Assessment Biomechanics FAB System. Muscle activation patterns will be assessed using a surface EMG system. Two-way ANOVAs with post-hoc analyses will be used to compare the differences between groups and conditions. Results. The preliminary results indicate that the tennis player tends to maintain movement patterns when using the Wii but require more eccentric control during the follow-through phase. The non-players change the movement pattern and use more wrist instead of the shoulder to complete the task when playing Wii. Conclusion. Further results and analyses will be available and presented during the Research Day. Grant. This project is sponsored by the President’s Faculty Research and Development Grant FY 2010