Frontiers in Sports and Active Living最新文献

Introduction: Hypoxic training protocols have been used to improve athletes' performance by influencing both physiological and emotional responses. The aim of the present study was two-fold. First, to evaluate the post-exercise emotional response on the increasing intensity exercise (O_2max) in normoxia and hypoxia. Second, to assess the emotional responses of two hypoxic training protocols (Sleep High-Train Low, SH-TL; Sleep Low-Train High, SL-TH) during increasing intensity exercise (O_2max) in both normoxia and hypoxia.

Methods: Twenty-seven physically active males ranging in age from 18 to 30 years volunteered to participate in the study. The participants were randomly assigned into two different hypoxic training protocols (SH-TL, SL-TH), and a control group. Participants performed a protocol to evaluate O_2max in hypoxia and in normoxia. The emotional responses were evaluated based the Activation Deactivation Adjective Check List and the Multidimensional Fatigue Inventory. Repeated measure analysis of variance was applied to examine the differences on participants' mood state and fatigue (energy, tiredness, tension, calmness, general fatigue, physical fatigue, reduced activity, reduced motivation, emotional fatigue) before and after the of O_2max before (pre-test), in the middle (middle-test), and in the end (post-test) of each training protocol.

Results: A significant change in energy in the SL-TH after O_2max was revealed compared to the other groups, between pre- and post-test. In the SH-TL condition, significant differences were found in energy and tension in normoxia, and in tension in hypoxia conditions. In the SL-TH group, significant differences were indicated in tiredness and calmness in normoxia. In hypoxic condition, significant changes were found in tiredness, tension, calmness and general fatigue.

Discussion: These findings point towards the effectiveness of SL-TH in managing fatigue and maintaining positive emotions. The effect of hypoxic training was noticed in participants mood state, highlighting the importance of a proper design aiming to improve humans' performance in hypoxic and normoxic conditions.

Background: Heart Rate Variability (HRV) is a crucial non-invasive marker of autonomic nervous system function, extensively applied in sports science for monitoring training load, fatigue, recovery, and performance optimization. The rapid expansion and diversification of HRV research necessitate a comprehensive bibliometric analysis to map the knowledge structure and emerging trends.

Objective: This study employed innovative bibliometric visualization to quantitatively analyze the literature landscape, research hotspots, and evolutionary trends in HRV applications within sports from 2010 to 2025. It aimed to identify key contributors, delineate major research themes, uncover nascent directions, and identify emerging research trajectories.

Method: Utilizing CiteSpace 6.3.R1 and VOSviewer, we conducted a comprehensive visual analysis of 1,660 articles retrieved from the Web of Science Core Collection and Scopus databases. This study performed co-authorship, co-citation, keyword co-occurrence, cluster analysis, and burst detection to unveil publication trends, collaborative networks, influential works, core authors, research hotspots, and emerging trends.

Results: Publication volume showed a significant growth trend, peaking in 2022 with 209 articles. The USA and Brazil were the most productive countries, with the University of São Paulo leading institutionally. Document co-citation analysis identified five major research hotspots: Athlete Monitoring, Biofeedback, Sport-related Concussion, Anxiety, and Endurance Exercise. Keyword burst analysis revealed three dominant future trends: "Sleep," "Machine Learning," and "Anxiety".

Conclusion: This bibliometric analysis delineates the evolution of HRV research in sports, confirming established domains while highlighting the importance of HRV's role in concussion management and psychological assessment. Critically, it highlights the field's evolving trajectory, emphasizing the growing integration of sleep interactions, machine learning-driven personalization, and the dynamics of HRV and anxiety. These findings provide a structured roadmap for future research and practical applications.

Introduction: This study aimed to elucidate specific muscle coordination patterns in a Paralympic gold medal wheelchair tennis player. Recent neuroscience has proposed the concept of the "Paralympic brain", referring to use-dependent and impairment-specific plasticity observed in some Paralympians. Although the present study does not directly assess neural reorganization, this framework provides context for interpreting motor coordination strategies.

Methods: We applied muscle synergy analysis of electromyographic (EMG) activities during the tennis serve to quantify muscle coordination in two male players: one a Paralympic and world champion (P1; osteosarcoma with hip and abdominal resections), and the other nationally ranked sub-elite player (P2; spina bifida with paralysis of the lower limbs and trunk). EMGs from 14 muscles and high-speed video were recorded during three flat serves.

Results: Serve velocity was markedly higher in P1 (167 ± 11.3 km/h) than P2 (80.0 ± 8.9 km/h). Four synergies were identified in P1 and three in P2. A specific synergy (Syn1), dominant in the early takeback phase and involving lower trapezius and triceps brachii, was found only in P1 and may contribute to greater trunk rotation and serve velocity. In addition, the sparseness of muscle synergies was also higher in P1 than in P2.

Discussion: These results indicate that elite serve performance is supported not only by muscular strength but also on specialized neuromuscular coordination strategies optimizing trunk rotation and energy transfer. They may be consistent with broader ideas of use-dependent and impairment-related adaptation described in the "Paralympic brain" framework. This study provides new insights into adapted motor strategies in Paralympic sport, underscoring the role of trunk control and residual function as key factors in training and performance optimization.

Introduction: Body tracking systems are utilized in various areas such as health and sports. In these areas, it is crucial to identify the most accurate and appropriate system for the intended design of the study.

Methods: This study evaluates the reliability of markerless motion capture systems compared to a marker-based system (OptiTrack) as the gold standard. The systems assessed include StereoLabs ZED 2i, MediaPipe (2D and 3D), and YOLOv8 Pose (8n and 8x-p6). Simple upper and lower limb movements were analyzed under controlled conditions in a single participant. Intraclass Correlation Coefficient (ICC) values and Bland-Altman analysis were mainly used to evaluate agreement between systems, with some other techniques explored to provide additional perspective.

Results: The results indicate that StereoLabs ZED 2i achieved the highest reliability among markerless systems (ICC: 0.92 for multi camera, 0.88 for single stereo camera), while MediaPipe 2D showed competitive performance (ICC: 0.85).

Discussion: In providing comprehensive evaluations and uncovering performance differences that have been largely overlooked in the literature, our work not only questions existing paradigms but also lays a foundation for future research aimed at developing precise and scalable motion-tracking technologies. These findings contribute to understanding the applicability of markerless technologies in biomechanics.

Introduction: This study examined changes in hair cortisol concentration (HCC) and hair oxytocin concentration (HOC) in female athletes and aimed to clarify their relationships with training load, daily life stressors, and mental health indicators.

Methods: Hair samples were collected from 22 female university soccer players (age: 19.8 ± 0.8 years), and psychological assessments were conducted in February and March 2024. Cortisol and oxytocin were extracted and measured from hair, and their associations with mood states [measured using the Profile of Mood States 2nd Edition (POMS2)], psychological distress [measured using the Kessler Psychological Distress Scale-6 (K6) scale], and self-reported training load were analyzed.

Results: Training load and POMS fatigue levels increased significantly from February to March (t = 4.27, P < 0.001 and t = 4.74, P < 0.001, respectively); however, despite these increases in physical demands and perceived fatigue, no significant changes were observed in HCC and HOC. Regression analysis using M-estimation revealed that changes in academic stress were significantly negatively associated with HCC changes (β = -1.04, p = 0.026), and changes in training load showed a positive association trend with HOC changes (β = 0.0003, p = 0.068). Spearman correlation analysis showed a significant negative correlation between HCC changes and POMS vigor changes (rs = -0.44, p = 0.039) and a significant positive correlation between HOC changes and K6 scale changes (rs = 0.43, p = 0.043). No significant correlation was found between HCC and HOC.

Discussion: HCC and HOC fluctuated independently and were associated with distinct psychological outcomes: HCC changes correlated with vigor, while HOC changes correlated with psychological distress. These findings suggest that each hormone may capture different dimensions of chronic stress and psychological functioning.

Conclusion: Combined measurement of HCC and HOC may be useful in assessing chronic stress in female soccer players, providing complementary information for athlete health management.

Introduction: Neuromuscular training (NMT) has been recognized as an effective strategy for improving sensorimotor function and mitigating injury risk in athletic populations. This systematic review and meta-analysis evaluated the effects of NMT on dynamic and static stability in volleyball players. This review assessed potential moderators, including sex and body region.

Methods: Relevant randomized controlled trials published between 1 January 2015, and 30 June 2025, were identified through systematic searches of major electronic databases. The search was limited to English-language publications and was conducted across Web of Science, PubMed, the Cochrane Library, Scopus, ScienceDirect, and PEDro. Following the screening and eligibility assessment, seven studies met the inclusion criteria and were included in the final analysis.

Results: Random-effects meta-analysis indicated that NMT was associated with moderate improvements in overall stability [SMD = 0.63, 95% CI (0.35, 0.9), I2 = 67.5%]. Moderator analyses suggested that benefits were more apparent in the upper limb compared to the lower limb and showed sex specific adaptations: males exhibited greater improvements in upper limb stability, whereas females showed more pronounced effects in the lower limb.

Discussion: Potential optimization mechanisms include enhanced lower-limb biomechanical responses through plyometric training, improved upper-limb kinetic chain synergy, and increased proprioception. NMT induced gender differentiated patterns of stability improvement in volleyball athletes, with males benefiting more from upper-body training while female athletes demonstrated greater adaptability in enhancing lower-body stability.

Systematic review registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD420251146182, PROSPERO CRD420251146182.

Purpose: Recurrent ankle sprains in chronic ankle instability (CAI) individuals are strongly linked to impaired proprioception, but the specific mechanisms underlying these impairments remain incompletely understood. This is largely due to the complexity of the proprioceptive system, which comprises multiple sub-modalities such as kinesthesia, joint position sense, force sense, vibration sense and landing proprioception, with the characteristic deficits of these sub-modalities and their diagnostic sensitivity and specificity remaining unclear. This study aims to comprehensively assess proprioception in CAI individuals by pointing sub-modality deficits, and to identify the core sub-modality with the greatest clinical discriminative value for CAI.

Methods: Fifty-eight participants were recruited, including 29 with CAI and 29 healthy controls. They underwent a battery of proprioceptive assessments: kinesthesia via the Threshold to Detect Passive Movement (TTDPM) test, joint position sense through the Joint Position Reproduction (JPR) test, force sense with the Force Match (FM) test, vibration sense using the Vibration Detection Threshold test, and landing proprioception evaluated by the Ankle Inversion Discrimination Apparatus for Landing (AIDAL) test. Between-group differences were analyzed using independent samples t-tests, Mann-Whitney U tests, and AUC tests.

Result: Higher passive perception thresholds in TTDPM tests (dorsiflexion: p = 0.03; inversion: p = 0.004; eversion: p = 0.018), higher absolute errors in FM tests (plantarflexion: p = 0.025; dorsiflexion: p = 0.043; inversion: p = 0.018; eversion: p = 0.014) and lower AIDAL score (p = 0.002) were detected in people with CAI. ROC curve analysis of the tests with significant intergroup differences revealed that the AIDAL exhibited the highest discriminative ability (AUC = 0.728).

Conclusion: Proprioceptive deficits in CAI are modality-specific, primarily affecting kinesthesia, force sense, and landing proprioception. Among the impaired sub-modalities, landing proprioception has the strongest predictive value for CAI and can serve as a key target for clinical assessment and rehabilitation intervention.

Introduction: Competitive outcomes in combat sports depend not only on functional preparation but also on athletes' ability to quickly adapt under pressure and make effective decisions in rapidly changing situations. The use of virtual reality (VR) as a tool for assessing cognitive functions has not yet been thoroughly validated in this context. The VR tasks used in this study do not measure higher-order cognitive functions such as executive function or anticipation; instead, they focus on observable performance metrics, such as reaction time, accuracy, and motor variability. The aim of the present study was to compare the level of cognitive functions in Brazilian Jiu-Jitsu (BJJ) athletes with varying levels of expertise.

Methods: Ten male BJJ practitioners (average age was 27.20 ± 5.63 years) were categorized into professionals (average training experience 11.00 ± 1.41 years; brown/black belts) and semi-professionals (average training experience 5.40 ± 1.14 years, blue/purple belts). VR based cognitive tests assessed reaction time, accuracy, and spatial awareness. The Mann-Whitney U test was applied to compare group performance.

Results: The professional group showed higher decision-making accuracy and slower reaction times; however, these patterns should be interpreted cautiously, as the study design does not allow attribution to underlying strategies or processes. The semi-professionals, on the other hand, exhibited greater variability in motor responses. Some of the differences between groups reached statistical significance (p < 0.05), although these should be interpreted cautiously due to the small sample size. The relationship between experience level and cognitive measures was inconsistent across parameters and should be considered preliminary, as the study was not powered to detect systematic associations.

Conclusions: Professionals appeared to score higher in accuracy-related measures and showed slower reaction times; however, these patterns should be interpreted as preliminary trends rather than evidence of differences in underlying mechanisms or strategic prioritization. Given the very small sample size and the exploratory nature of the study, no conclusions can be drawn about underlying cognitive mechanisms. The findings suggest preliminary, unstable patterns between expertise levels in selected cognitive measures; however, given the small sample size and exploratory design, no causal inferences regarding the influence of experience on cognitive functions can be drawn. The study also suggests that VR may have potential as an assessment tool, though its utility for evaluating BJJ-specific cognitive performance remains unvalidated and should be considered exploratory at this stage.

Introduction: Scapular motion tracking is essential for understanding shoulder kinematics, but its utility in individuals with high body mass index (BMI) requires further investigation. The purpose of this study was to define repeatability of skin-based scapular motion tracking in individuals with BMI ≥ 30 using two calibration procedures.

Methods: Nine participants (mean BMI (SD): 42.1 (7.9)) completed two sessions involving planar arm elevations and functional arm-focused tasks. Scapular motion was tracked with the acromial marker cluster, and scapular kinematics were calculated from single and double calibration procedures. Repeatability of discrete scapular angles at 15° increments of humeral elevation was evaluated using intraclass correlation coefficients (ICCs), and minimal detectable change (MDC). Differences in angle waveforms were also explored with statistical parametric mapping.

Results: Findings suggest that scapular motion tracking is feasible and repeatable for upward rotation and internal rotation in individuals with high BMI (ICCs = 0.50-0.90; MDCs = 5 to 15°). The single calibration method underestimated upward and internal rotation as compared to the double calibration method, particularly at higher humeral elevations.

Discussion: Although BMI was used as a proxy for body composition, this study supports scapular motion tracking with the acromial marker cluster in populations where soft tissue artifact may be more pronounced.