Nyeonju Kang

[목적] 본 연구는 축구선수들의 주발과 비주발에 대한 시각 정보의 유·무 및 과제 난이도가 발목 등척성 힘 제어 전략에 어떠한 영향을 미치는지 조사하는 데 목적을 두고 있다. [방법] 축구선수 13명 및 일반인 16명, 총 29명의 연구 대상자들이 각각 MVC의 10%와 40%의 힘 수준에서 시각 정보의 유·무에 따른 발목 등척성 힘 조절 과제를 수행하였다. 힘 조절 능력은 평균 힘, 정확성, 가변성, 규칙성(Sample entropy)을 통해 발목 등척성 힘 조절 전략을 평가하였다. 추가적으로 YANK 분석을 통해 시간에 따른 힘 변화의 부드러움을 나타내는 평활성을 계산하였다. [결과] 시각 정보의 유·무 및 과제 난이도에 따른 두 그룹 간의 평균 힘, 정확성, 및 가변성에 대한 유의미한 차이는 나타나지 않았다. 그러나, 비주발에서 축구선수들이 일반인들보다 유의미하게 낮은 규칙성을 보였으며, 평활성은 축구선수의 주발과 비주발 모두 일반인들보다 유의미하게 낮은 것으로 나타났다. [결론] 본 연구의 결과는 등척성 발목 힘 조절 과제 시 축구선수의 비주발에서 보인 낮은 규칙성과 평활성이 숙련된 엘리트 선수일수록 지속적으로 변화하는 환경이나 미세한 오차에 대응하여 고정된 힘 조절이 아니라 유연하게 힘을 발휘하려는 것을 의미한다. 이는 축구선수들이 실제 힘 조절 과정에서도 고도화된 적응성을 발휘하여 성공적으로 과제를 수행하려는 것으로 해석할 수 있다. 향후 연구에서는 다양한 스포츠 종목의 특성(e.g., 개방형 및 폐쇄형 운동기술)과 수행력을 반영하여 YANK 값이 관련 종목의 수행력을 예측할 수 있는 지표인지를 규명하는 연구가 필요할 것이다. PURPOSE This study compared unilateral force control capabilities between 13 elite soccer players and 16 healthy controls using the isometric ankle force control paradigm. METHODS Participants were instructed to perform unilateral ankle force control tasks across vision and no-vision conditions with their dominant and non-dominant ankles at 10% and 40% of their maximal voluntary contraction, respectively. Force control capabilities were analyzed using mean force, force accuracy, and force variability. Furthermore, force regularity and force smoothness were estimated using sample entropy (SampEn) and YANK analysis, respectively. RESULTS The groups did not differ significantly in mean force, force accuracy, and force variability across different visual conditions and targeted force levels. However, the soccer players showed significantly lower regularity (increased SampEn values) in the non-dominant lower limb and lower smoothness (increased YANK values) in both lower limbs during ankle isometric force control tasks. CONCLUSIONS These findings indicate that soccer players use more adaptive force control strategies in the lower extremities to successfully achieve task goals.

This review examined cumulative findings from recent meta-analyses to identify current challenges and possible suggestions for improving the effects of BCI systems on stroke motor recovery. Consistent with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a systematic literature search was conducted using PubMed, Web of Science, and the Cochrane Library on 30 June 2026. A total of 17 systematic reviews and meta-analyses were included. Among three motor intent-induced (i.e., motor attempt, motor observation, and motor imagery) modalities, motor attempt was the modality most consistently associated with significant therapeutic effects across meta-analyses. Electrical stimulation was a consistently effective feedback modality, whereas robot-assisted and visual feedback showed heterogeneous effects. Higher weekly session frequencies and moderate session durations (approximately 20–60 min) showed consistent motor recovery. Stroke type, age, intervention period, total sessions, total training time, and long-term effect durability were inconsistent across the included evidence. These findings suggest that applying BCI-based training is an effective rehabilitation program for the functional recovery of upper extremities in patients with stroke who have moderate to severe motor impairments, potentially achieving greater therapeutic efficacy when combining motor attempts with electrical stimulation.

Older adults normally showed impaired fine motor control capabilities, as indicated by increased force error and variability during submaximal force control tasks. However, whether aging additionally disrupts temporal smoothness of the force trajectory remains unclear beyond the magnitude of force fluctuation. This study investigated age-related changes in bimanual isometric force smoothness using YANK analysis (i.e., time-derivative of force; dF/dt). Fifteen younger adults (mean ± SD of age = 25.4 ± 2.5 years) and fifteen older adults (mean ± SD of age = 64.9 ± 6.5 years) performed bimanual hand-grip isometric force control at 10 % of maximum voluntary contraction across the vision and no-vision conditions. Force accuracy (relative root-mean-square error; rRMSE), variability (coefficient of variation; CV), smoothness (YANK), and interlimb force coordination (correlation coefficient) were quantified. Receiver operating characteristic (ROC) curve and Pearson’s correlation analyses were conducted to evaluate the discriminative ability of each variable and potential relationships between YANK and conventional force control variables. Older adults showed significantly higher YANK values than younger adults in both vision and no-vision conditions, indicating reduced force smoothness. Greater rRMSE, CV, and correlation coefficient values for older adults were observed only in the vision condition. The ROC curve analysis revealed that YANK effectively discriminated between the younger and older adults in both vision and no-vision conditions. For older adults, increased YANK was significantly correlated with greater rRMSE and CV in the vision condition and with greater CV in the no-vision condition, whereas no significant correlations appeared in younger adults. These findings suggest the YANK approach can capture age-related fine motor control deficits that conventional variability measures may overlook.

PURPOSE: This systematic review and meta-analysis aimed to investigate the effectiveness of breathing training in patients with panic disorder.METHODS: We acquired 25 comparisons across 9 qualified studies for data synthesis. Individual effect sizes (standardized mean difference; SMD) were estimated by comparing changes in the following physiological and psychological variables between breathing training and control conditions: (a) partial carbon dioxide (pCO2), (b) number of respirations per minute (RR), (c) panic disorder severity scale (PDSS), and (d) anxiety severity index (ASI).RESULTS: The random-effects model meta-analysis showed significant improvements in physiological and psychological variables after breathing training. For physiological variables, increased pCO2 levels (SMD=0.338; standard error [SE]=0.137; 95% confidence interval [CI]=0.070 to 0.607; Z=2.473; p<.013) and decreased RR (SMD=0.342; SE=0.144; 95% CI=0.059 to 0.624; Z=2.372; p<.018) were observed. For psychological variables, breathing training significantly reduced the PDSS (SMD=1.250; SE=0.347; 95% CI=0.570–1.930; Z=3.604; p<.001) and ASI scores (SMD=3.822; SE=1.430; 95% CI=1.019–6.625; Z=2.672; p<.008).CONCLUSIONS: Breathing training is a method with both physiological (pCO2 and RR) and psychological (PDSS and ASI) effectiveness and practicality for patients with panic attacks and panic disorders. Current studies on the application of breathing training as a treatment method to reduce panic disorders and attacks are insufficient. Therefore, future studies should include large-scale, long-term studies that apply breathing training to patients with panic disorders and attacks in Korea.

Bilateral force control and coordination in upper and lower limbs are important functions for executing activities of daily living. Although upper and lower limbs may reveal distinct bilateral motor control patterns because of different motor networks involvements, no one has examined the possibility that upper and lower limbs reveal distinct bilateral force control and coordination patterns. This study investigated bilateral force control and coordination patterns between upper and lower limbs in healthy young adults. Thirty-two healthy young adults (mean±SD of age = 23.2±2.2 years; 16 Females) performed bilateral hand-grip and ankle-dorsiflexion force control tasks at 10 % and 40 % of maximal voluntary contraction. Bilateral force control performances were evaluated by calculating mean force, force symmetry, force accuracy, and force variability. To estimate bilateral force coordination, we used cross-correlation with time lag. Further, we examined the relationship between bilateral force control and coordination patterns of upper and lower limbs by conducting Pearson’s correlation analysis. Bilateral maximal and mean forces of lower limbs were significantly less than those for upper limbs. At higher targeted force level, force accuracy and variability in lower limbs were significantly lower than those for upper limbs. More negative correlation coefficient values appeared in lower limbs as compared with upper limbs. Finally, bilateral force control performances in upper limbs were related to those in lower limbs although no significant correlation was observed for interlimb coordination patterns. These findings suggest that bilateral motor control and coordination patterns were different between upper and lower limbs although the level of bilateral upper and lower motor control capabilities was presumably influenced by shared motor control processes for each individual.

This study aimed to determine whether vagus nerve stimulation is effective in modulating psychological states such as anxiety, depression, and stress in elite shooters. A total of 18 female elite shooters (aged 18–19 years) were randomly assigned to either an experimental group (n = 9) or a control group (n = 9). The experimental group received vagus nerve stimulation for 30 min per session, once daily, seven days a week, over a period of four weeks. Psychological variables were assessed at three time points: pre-test (baseline), mid-test (2 weeks), and post-test (4 weeks). Two-way repeated measures ANOVA revealed significant group × time interactions for stress (p < 0.01), cognitive anxiety (p < 0.001), somatic anxiety (p < 0.01), confidence (p < 0.001), and depression (p < 0.01). Paired t-tests demonstrated significant reductions in stress, cognitive anxiety, somatic anxiety, and depression, as well as a significant increase in confidence within the experimental group. These findings provide compelling evidence that a 4-week course of vagus nerve stimulation can reduce stress, anxiety, and depression while enhancing confidence in elite shooters. Therefore, this intervention may serve as a beneficial strategy for improving mental health in elite shooters.