# Reaction Time and Postural Control Under Dual-Task Conditions in Brazilian Jiu-Jitsu Athletes
## 4 Discussion
This finding aligns with the demands of Brazilian Jiu-Jitsu, where athletes must continuously adapt their balance to counter unpredictable movements and maintain stability during grappling scenarios. In contrast, the control group exhibited higher FD_AP_leos values compared to Brazilian Jiu-Jitsu athletes during one-legged standing while tracking a chaotically moving dot. A higher fractal dimension indicates a more complex CoP trajectory, which could reflect the control group's greater difficulty in maintaining stability during this cognitively demanding task. The lower FD values in Brazilian Jiu-Jitsu athletes suggest that their training allows them to simplify their postural control strategy under challenging conditions, maintaining effective stability without unnecessary complexity. These findings demonstrate that Brazilian Jiu-Jitsu training fosters a balance system that is both adaptive and efficient. While athletes displayed greater adaptability in tasks requiring single-leg standing (LyE_ML_1 eo), they also showed more efficient and stable postural control strategies in simpler tasks (SampEn_ML_2 eo) and cognitively demanding conditions (FD_AP_leos). These differences highlight the sport-specific benefits of Brazilian Jiu-Jitsu, which involves frequent dynamic shifts in posture, maintaining balance under pressure, and responding to complex environmental stimuli. The last part of this paper looked at patterns of observed correlations in the control group and Brazilian jiu-jitsu athletes, highlighting differences in their postural control and response strategies. In the control group, only two significant correlations were observed. A moderate positive correlation (R = 0.61, \(p\) < 0.05) was found between the number of lights turned off in the sitting position and SampEn_AP_leos, suggesting that participants with more irregular CoP signals in the anteroposterior (AP) direction performed better in light-switching tasks. Conversely, a moderate negative correlation (R = \(-\)0.53, \(p\) < 0.05) between reaction time in the standing position and SampEn_AP_leos indicated that participants with faster reaction times exhibited more regular CoP signals, possibly reflecting a more rigid postural control strategy. In contrast, Brazilian Jiu-Jitsu athletes demonstrated a more complex interplay between postural control and task performance, with nine significant correlations identified. Negative correlations were observed between the number of lamps switched off and LyE_AP_leo (R = \(-\)0.62, \(p\) < 0.05) and LyECoP_ML_1 eos (R = \(-\)0.61, \(p\) < 0.05) during standing tasks, as well as LyE_AP_1 eo (R = \(-\)0.80, \(p\) < 0.05) and LyECoP_ML_1 eos (R = \(-\)0.58, \(p\) < 0.05) during sitting tasks. These moderate to high negative correlations suggest that athletes who performed better in light-switching tasks exhibited less variability in their postural dynamics, likely reflecting greater postural control efficiency. Positive correlations were also observed in the athlete group. Moderate correlations were noted between reaction time (in both positions) and LyE_AP_1 eo (R = 0.57, \(p\) < 0.05) and LyECoP_ML_1 eos (R = 0.64, \(p\) < 0.05 for standing, R = 0.81, \(p\) < 0.05 for sitting). This indicates that longer reaction times were associated with more dynamic and adaptable postural control, as reflected by higher LyE values. Furthermore, a moderate positive correlation (R = 0.54, \(p\) < 0.05) between the number of lamps switched off in the standing position and LyECoP_ML_2 eos suggests that greater postural adaptability in the mediolateral (ML) direction supported better task performance. A review of the literature reveals that no previous studies have combined reaction time analysis with nonlinear postural control parameters. However, research has investigated dual-task performance in athletes, including Taekwon-do practitioners [26; 48].