| Keywords |
Korean traditional archery; Muscle fatigue; Electromyography (EMG); Near-infrared spectroscopy (NIRS); Muscle oxygen saturation (SmO2); Maximal holding phase |
| Abstract |
Korean traditional archery requires prolonged isometric muscle contraction during the maximal holding phase. This study investigated muscle fatigue characteristics during Korean traditional archery by simultaneously analyzing muscle activation and muscle oxygen saturation. Twenty-eight experienced Korean traditional archers (42.0 ± 18.4 aged) participated in this study. Surface electromyography (EMG) and near- infrared spectroscopy (NIRS) were simultaneously used to assess the posterior deltoid (PD), middle trapezius (MT), and triceps brachii (TB) of the draw arm (DA) and bow arm (BA). Muscle activity was quantified using normalized EMG amplitude (%MVC) and mean frequency (MNF), whereas muscle oxygen saturation (SmO2) was used as an index of local muscle oxygenation. Variables were analyzed at full draw, release, and across four time-normalized quartiles during the maximal holding phase. During the maximal holding phase, %MVC progressively increased in all muscles and was significantly greater in the BA than in the DA (p < .01~.001). In contrast, MNF progressively decreased from full draw to release and across quartiles in both arms (p < .001), indicating the development of neuromuscular fatigue. SmO2 also decreased significantly over time, with greater reductions observed in the BA of PD and TB compared with the DA (p < .05~.001). Correlation analyses revealed negative associations between SmO and %MVC and between %MVC and MNF, whereas SmO was 2 2 positively correlated with MNF (p < .01). The maximal holding phase of Korean traditional archery induces concurrent neuromuscular and hemodynamic fatigue. The posterior deltoid (PD) and triceps brachii (TB) of the bow arm (BA) exhibited the greatest fatigue-related responses, suggesting that these muscles play a critical role in maintaining shooting stability. Combined EMG and NIRS assessment may provide a useful approach for monitoring fatigue and developing evidence-based training strategies for traditional archers. |