Examining the effects of computer mouse sensitivity on upper extremity muscle activity and kinematics in video game players

Abstract

Computer mice are a primary component of human-computer interfaces in both office and video game settings, with video game players adjusting their mouse sensitivity to optimize performance. Limited data exists on how mouse sensitivity affects muscle activity and kinematic during video gaming. Differing movement strategies are associated with changes in mouse sensitivity, as lower sensitivity requires larger mouse movements for the same cursor movements. Therefore, the purpose of this investigation was to assess mouse sensitivity’s effects on muscle activity, arm kinematics, while investigating skill level and game difficulty effects. Thirty-four participants, classified as experienced or casual players, played a rhythm-based target acquisition game called osu! (ppy Pty Ltd), while using a mouse set at three sensitivities. Mouse sensitivity was set at low (400 DPI), high (1600 DPI) and preferred (mean=921 DPI). Participants played 7 trials per mouse sensitivity; 3 with the closest accuracy were analyzed. Experienced participants completed both easy- and hard-difficulty beatmaps. Kinematics and EMG data from the right upper limb and torso were compared across mouse sensitivities and between participant skill level or game difficulty. Main effects of sensitivity revealed a consistent relationship in muscle activity levels, where muscle activation was 40+% higher in the upper trapezius, supraspinatus, infraspinatus, and extensor carpi ulnaris while using the mouse at a low sensitivity compared to high or preferred. Mean muscle activity was within ranges of 1-6 %MVC across sensitivities, while peaking up to 23 %MVC in extensor carpi ulnaris, which combined with long play times may result in signs of muscle fatigue (Jørgensen et al., 1987, Jonsson et al., 1978). Sensitivity effects in kinematics only emerged in wrist radial deviation across mouse sensitivities, with low sensitivity revealing 6° more wrist deviation than high sensitivity. Shoulder kinematics differed between skill groups, as experienced players demonstrated more shoulder abduction and internal rotation, with mean postures differing by 10° and 4°, respectively. Lastly, more difficult gameplay resulted in significantly higher muscle activation across most muscles. This thesis offers novel insights into how the effects of mouse sensitivity on muscle activity and posture, which can assist clinicians with further understanding potential causes of injury prevalence in computer mouse users.