Esports and Physiological Tremor a StarCraft 2 Tournament Study

Andrzej Białecki, Izabela Ghafour, Szymon Kuliś, Maciej Skorulski, Jan Gajewski

Physiological tremor of the upper limb is a sensitive neuromuscular indicator that may be modulated by cognitive load and competitive stress, yet its behaviour in real esports conditions remains uncharacterised. We measured wrist accelerometer-based tremor in 16 healthy adult male StarCraft~2 players across two tournament days, computing log power spectral density ($log(PSD)$) and dominant frequency in four bands (2--4, 8--14, 10--20, and 1--25Hz) and comparing them to published population norms using linear mixed models. Players deviated significantly from the reference in all bands: $log(PSD)$ was elevated at 2--4~Hz and substantially reduced at higher frequencies (Cohen's $d = 1.6$--$2.3$), suggesting long-term neuromuscular adaptation to the fine-motor demands of esports. Tremor indicators declined systematically over the tournament day. Contrary to the fatigue-related increases typical of traditional motor tasks. Neither game outcome nor actions per minute significantly predicted post-game tremor. These findings suggest physiological tremor may reflect a generalised psychophysiological adaptation to competitive esports rather than being a short-term performance predictor.