Celal Bulgay
57204125387
Publications - 14
Genetic Factors of Elite Wrestling Status: A Multi-Ethnic Comparative Study
Koichi Nakazato
Ildus I. Ahmetov
Seyrani Koncagul
Hirofumi Zempo
Mehmet A. Ergun
Andrey K. Larin
Naoki Kikuchi
Nikolay A. Kulemin
Hasan H. Kazan
Ryutaro Matsumoto
Ekaterina A. Semenova
Edward V. Generozov
Celal Bulgay
Mika Saito
Hiroki Homma
Ayumu Kozuma
Minoru Deguchi
Anıl Kasakolu
Shingo Matsumoto
Türker Bıyıklı
Giyasettin Baydaş
Takanobu Okamoto
Attila Szabo
Publication Name: Genes
Publication Date: 2025-08-01
Volume: 16
Issue: 8
Page Range: Unknown
Description:
Background: In recent years, comprehensive analyses using a genome-wide association study (GWAS) have been conducted to identify genetic factors related to athletic performance. In this study, we investigated the association between genetic variants and elite wrestling status across multiple ethnic groups using a genome-wide genotyping approach. Methods: This study included 168 elite wrestlers (64 Japanese, 67 Turkish, and 36 Russian), all of whom had competed in international tournaments, including the Olympic Games. Control groups consisted of 306 Japanese, 137 Turkish, and 173 Russian individuals without elite athletic backgrounds. We performed a GWAS comparing allele frequencies of single-nucleotide polymorphisms (SNPs) between elite wrestlers and controls in each ethnic cohort. Cross-population analysis comprised (1) identifying SNPs with nominal significance (p < 0.05) in all three groups, then (2) meta-analyzing overlapped SNPs to assess effect consistency and combined significance. Finally, we investigated whether the most significant SNPs were associated with gene expression in skeletal muscle in 23 physically active men. Results: The GWAS identified 328,388 (Japanese), 23,932 (Turkish), and 30,385 (Russian) SNPs reaching nominal significance. Meta-analysis revealed that the ATP2A3 rs6502758 and UNC5C rs265061 polymorphisms were associated (p < 0.0001) with elite wrestling status across all three populations. Both variants are located in intronic regions and influence the expression of their respective genes in skeletal muscle. Conclusions: This is the first study to investigate gene polymorphisms associated with elite wrestling status in a multi-ethnic cohort. ATP2A3 rs6502758 and UNC5C rs265061 polymorphisms may represent important genetic factors associated with achieving an elite status in wrestling, irrespective of ethnicity.
Open Access: Yes
Positive and Negative Expectations Associated with Coffee and Energy Drinks: Implications for Placebo–Nocebo Research in Sports
Publication Name: Nutrients
Publication Date: 2025-02-01
Volume: 17
Issue: 4
Page Range: Unknown
Description:
Background: Nutritional expectations have been shown to influence exercise performance via placebo and nocebo effects. The present study aimed to evaluate performance-enhancement expectations for coffee and energy drinks using the Stanford Expectations of Treatment Scale. Methods: A total of 402 participants (48.5% male) with an average exercise history of 4.53 years, engaging in average physical activity 3.91 times per week, were included in the study. Data collection was conducted through the Qualtrics platform. Results: Participants exhibited significantly higher positive expectations for coffee compared to energy drinks (p = 0.002), whereas negative expectations were more pronounced for energy drinks than for coffee (p < 0.001). Males and individuals engaging in anaerobic exercise expressed more positive expectations for energy drinks than females and those participating in aerobic or mixed exercise regimens. Additionally, high-frequency exercisers (≥4 sessions per week) reported greater positive expectations for both beverages and fewer negative expectations for coffee than low-frequency exercisers (≤3 sessions per week). Correlational analyses revealed weak but significant associations between expectations and variables such as exercise history, frequency, intensity, and age. Conclusions: The findings suggest that coffee is perceived as a more effective performance enhancer and exhibits greater placebo-inducing potential than energy drinks, which may elicit stronger nocebo effects. These group-specific perceptions should be considered by trainers, coaches, and researchers when addressing placebo–nocebo mechanisms in the context of sports and exercise.
Open Access: Yes
DOI: 10.3390/nu17040628
Genome-Wide Association Study of Exercise Addiction Among Elite Wrestlers
Publication Name: Brain Sciences
Publication Date: 2025-02-01
Volume: 15
Issue: 2
Page Range: Unknown
Description:
Background: Exercise addiction, marked by an inability to control exercise and associated with distress that clinically impairs daily activities, is a significant but underrecognized issue in physical activity and health. While its physiological, psychological, and behavioral aspects have been studied, the genetic basis of exercise addiction remains poorly understood, requiring further investigation. The present study conducted a genome-wide association study of exercise addiction among elite Turkish wrestlers. Methods: The sample comprised 67 male wrestlers (34 freestyle wrestlers and 33 Greco-Roman wrestlers). Exercise addiction was assessed using the Exercise Addiction Scale. Whole-genome genotyping was performed using DNA microarray. Results: Using a genome-wide approach (p < 1.0 × 10−⁵), we identified six suggestively significant single-nucleotide polymorphisms (SNPs) associated with exercise addiction status. Of these, the high-addiction alleles of five SNPs (PRDM10 rs74345126, near PTPRU rs72652685, HADHB rs6745226, XIRP2 rs17614860, and near GAREM2 rs1025542) have previously been associated with an increased risk of mental health disorders such as anxiety and depression or higher levels of physical activity. We also examined potential associations between the genetic markers previously linked to addiction-related traits such as obsessive–compulsive disorder and cigarette smoking, and personality traits linked to negative emotions including neuroticism. Using this candidate gene approach (p < 0.05), we identified three additional SNPs associated with exercise addiction in the same direction of association (DEFB135 rs4841662, BCL11A rs7599488, and CSRNP3 rs1551336). Conclusions: The present study provides preliminary evidence for the genetic basis of exercise addiction, highlighting specific SNPs that may play a role in the development of this condition among elite wrestlers.
Open Access: Yes
Body Mass and Aerobic Capacity are Robust Predictors of the 2000m Ergometer Rowing Performance: A Laboratory Study
Publication Name: International Journal of Kinesiology and Sports Science
Publication Date: 2025-01-01
Volume: 13
Issue: 2
Page Range: 78-85
Description:
Purpose: Predicting performance in sports competitions is a popular topic in research. However, only a few studies exist in rowing sports, which suggest that some anthropometric and performance indices might predict performance in various situations. Methods: This work expands past research by examining the effects of five anthropometric measures, such as body mass index (BMI), height, weight, fat, and muscle, and three performance indicators, such as aerobic capacity, maximum speed, and force, while also considering the training history of 38 elite rowers (Mag e = 16.89 ± 1.85, range 14.7 to 22.6 years, 61% males) participating in a national championship. Results: Apart from BMI, all measures correlated statistically significantly with the 2000m rowing time. A bootstrapped forward multiple regression yielded the best model with only two predictors (R2 =.995), aerobic capacity and body mass, accounting for 99.5% variance in the 2000m rowing time. Conclusions: While the results support previous findings, such robust prediction has not been reported in the literature. We conjecture that the differences from other past works rest with the high-pressure 2000m performance preceding a national championship. If these findings could be replicated, their practical implication is substantial in preparatory training for rowing contests.
Open Access: Yes
Association between hand grip strength and exercise addiction among high-level athletes: differences by sport category and sex in elite athletes
Publication Name: Frontiers in Psychology
Publication Date: 2025-01-01
Volume: 16
Issue: Unknown
Page Range: Unknown
Description:
Introduction: Handgrip strength (HGS) is a key indicator of upper-body strength and overall physical fitness. While its links to health and sports performance have been widely studied, its relationship with the risk of exercise addiction (REA) remains unclear. Thus, the present study examines the relationship between HGS and REA across various sports disciplines, sexes, and national contexts, aiming to deepen our understanding of their intricate interplay. Methods: Using a cross-sectional research design, data were collected from 1,211 high-level athletes from Türkiye (n = 656) and Hungary (n = 555), spanning a wide range of competitive sports. The measures involved demographic questions, the Exercise Addiction Inventory to assess REA, and HGS assessments. Results: We found significant negative correlations between HGS and REA among Turkish female athletes competing in racquet and water sports (p < 0.05). In contrast, significant positive correlations emerged in team sports played with hands and target-based sports (p < 0.05). Statistically significant HGS-REA correlations were also observed among Turkish male athletes participating in gymnastics and esthetic sports (p < 0.05). Among Hungarian athletes, a significant HGS-REA correlation was found in male racquet sports athletes and female athletes engaged in combat sports (p < 0.05). Regardless of sports discipline, a statistically significant positive correlation was observed exclusively among Turkish female athletes (p < 0.05). Conclusion: The present study reveals that the correlations between HGS and the risk of REA may vary depending on country, sex, and type of sport. The findings indicate that HGS may be either positively or negatively associated with REA in specific sports disciplines.
Open Access: Yes
Exercise Addiction: a Thematic Analysis of Self-Reported Cases for Clinical Insight and Prevention
Publication Name: International Journal of Mental Health and Addiction
Publication Date: 2025-01-01
Volume: Unknown
Issue: Unknown
Page Range: Unknown
Description:
Exercise addiction (EA) is a potentially harmful behavioral disorder that remains clinically undefined, with research often relying on symptom-based models that overlook subjective experiences. This study reviewed 63 self-reported EA cases using Braun and Clarke’s thematic analysis to identify recurring experiential patterns that may go beyond the component model of addictions (CMA). Nine themes emerged: loss of control, diverse exercise engagement, identity fusion, emotional coping, social disconnection, health denial, gender disparity, compulsive quantification, and severe physical consequences. The findings provide ecologically valid insights into the psychological and social dynamics of EA. Some themes partially overlapped with the CMA, but also with obsessive passion and self-determination, highlighting the limitations of current research frameworks and the need for more inductive, person-centered approaches. The results have practical implications for prevention, early detection, and intervention strategies and contribute to the ongoing effort to establish clinical diagnosis criteria for EA.
Open Access: Yes
COVID-19 Alters Respiratory Function Associations in High-Level Athletes
Publication Name: Medicina Lithuania
Publication Date: 2025-09-01
Volume: 61
Issue: 9
Page Range: Unknown
Description:
Background and Objectives: Coronavirus disease 2019 (COVID-19) has affected multiple physiological systems, including respiratory function, which is critical for athletic performance. Although alterations in pulmonary dynamics have been observed in high-level athletes recovering from COVID-19, the effects on respiratory function remain unclear. In this context, the present study aimed to examine the impact of COVID-19 on the interrelationships among respiratory function parameters in high-level athletes. Materials and Methods: Sixty-eight high-level athletes participated in the present study, including 34 with a history of COVID-19 and 34 controls without prior infection. Respiratory function and respiratory muscle strength were assessed using a digital spirometer (Pony FX, Cosmed, Italy). Key variables included Forced Vital Capacity (FVC), Peak Expiratory Flow (PEF), Maximum Voluntary Ventilation (MVV), Forced Expiratory Volume in one second (FEV1 ), and Maximum Inspiratory/Expiratory Pressure (MIP/MEP). Results: High-level athletes with prior COVID-19 infection exhibited significant differences in the correlations (p < 0.05) between FVC and PEF, FVC and MVV, FEV1 and FEV1 /FVC, and MIP and MVV compared to controls. Conclusions: These findings suggest that COVID-19 can disrupt the interrelationships among respiratory function parameters in high-level athletes, highlighting the need for further longitudinal investigations.
Open Access: Yes
Quantifying the relationship between physical performance and mental wellbeing in older adults: a field study
Publication Name: Frontiers in Aging
Publication Date: 2025-01-01
Volume: 6
Issue: Unknown
Page Range: Unknown
Description:
Introduction: Although the relationship between functionality, as reflected in physical performance (PHP), and mental health in older adults has been researched, its strength remains unclear. Methods: This field study aimed to determine the strength of this relationship in adults aged 60 and above using seven PHP indices and six psychological measures. We individually tested 114 older adults. Objective measures included six PHP indices consisting of the Senior Test and handgrip strength. Subjective measures included resilience, wellbeing, happiness, perceived stress, hopelessness, and life satisfaction. Results: Structural equation modeling (SEM) revealed two latent constructs: PHP and mental wellbeing (MWB): robust fit (MLR): X2 (75) = 136.28, p < 0.001; CFI = 0.967; TLI = 0.960; RMSEA = 0.066 (90% CI [0.000, 0.128]); SRMR = 0.088. The latent partial correlation between PHP and MWB (adjusted for Age) was φ = 0.46, indicating ∼21% shared variance. The correlation between the two latent factors was moderate (r = 0.46), suggesting that other unassessed factors might account for the relationship. Discussion: Based on objective PHP and subjective MWB measures, these results suggest a modest connection, with the two latent constructs sharing ∼1/5 of their variances. Consequently, further research is needed to identify other factors affecting the studied relationship in older adults. These cross-sectional findings, suggesting a moderate association, should be interpreted with caution. Still, they support recommending physical activity as one component of broader, multi-domain strategies to support the wellbeing of older adults.
Open Access: Yes
Association of ANKK1 and DRD2 gene polymorphisms with exercise addiction among elite athletes
Publication Name: International Journal of Sport and Exercise Psychology
Publication Date: 2025-01-01
Volume: Unknown
Issue: Unknown
Page Range: Unknown
Description:
Exercise addiction is a behavior that may dysregulate athletic performance, and social and professional interactions of athletes. Whereas environmental factors including training routines and personal traits could contribute to exercise addiction, recent studies have emphasized the importance of genetic predisposition, leading to development of a subfield known as sports psychogenetics. In sports psychogenetics, ankyrin repeat and kinase domain containing 1 (ANKK1) and dopamine receptor D2 (DRD2) genes, located on chromosome 11 in a close proximity, have attracted research interest due to their involvement in dopaminergic signaling playing a crucial role in reward processing, motivation, cognition and behavior. Therefore, the present study aimed to investigate potential associations between 14 polymorphisms in ANKK1/DRD2 and exercise addiction among elite badminton players (n = 39) and elite wrestlers (n = 68). Exercise addiction was assessed using a psychometric screening instrument and allele frequencies of the selected polymorphisms were analyzed through genotyping with a single nucleotide polymorphism (SNP) microarray. Results indicated that two SNPs, rs7118900 and rs4436578, were significantly and independently associated with exercise addiction. Rs7118900 has previously been associated with an increased risk of drug addiction, neuroticism, and depressed effect whereas rs4436578 has been associated with neuroticism. In addition to those SNPS, rs2283265 and rs1125394 SNPs were also linked to exercise addiction in a branch-independent manner. Therefore, it is proposed that these SNPs could serve as genetic markers for identifying individuals at high risk of exercise addiction among athletes. However, further research is needed to understand the involvement of these SNPs in exercise addiction more comprehensively.
Open Access: Yes
Passion and Addiction in Aerobic, Anaerobic, and Mixed (CrossFit) Exercises
Publication Name: Studia Sportiva
Publication Date: 2025-01-01
Volume: 19
Issue: 2
Page Range: 235-249
Description:
This study employed exercise dependence and four-phase models to investigate the relationship between passion for exercise and the risk of exercise addiction (REA) among practitioners of aerobic, anaerobic, and CrossFit exercises. Participants (N = 424; 60.8% female; meanage = 38.29 ± 9.71 years) were recruited from fitness centers and social media in Hungary. The sample included 234 CrossFit, 126 aerobic (e.g., running, cycling, swimming), and 64 anaerobic (bodybuilding) exercisers. Data were collected online on Qualtrics, which included demographic questions, the Exercise Addiction Inventory-3, and the Passion Scale-8. CrossFit participants exhibited the highest exercise frequency and intensity, with a greater prevalence of REA (25.2%) compared to the anaerobic (15.6%) and aerobic (14.3%) groups. Cross Fitters also scored higher on salience, withdrawal symptoms, and passion. However, group differences in absolute REA scores vanished after controlling for passion and exercise characteristics. Gender differences emerged, with females showing a stronger affective connection to exercise and higher withdrawal symptoms. Passion was strongly correlated with REA (r = 0.55) and accounted for 28% of the variance in it. Further research is needed to distinguish between passion-driven exercise and addiction.
Open Access: Yes
DOI: 10.5817/StS2025-2-17
Correction: Association between hand grip strength and exercise addiction: differences by sport category and sex among elite athletes (Frontiers in Psychology, (2025), 16, (1597239), 10.3389/fpsyg.2025.1597239)
Publication Name: Frontiers in Psychology
Publication Date: 2025-01-01
Volume: 16
Issue: Unknown
Page Range: Unknown
Description:
Sport Psychology The title of this article was erroneously given as: Association between hand grip strength and exercise addiction among high-level athletes: differences by sport category and sex in elite athletes. The correct title of the article is: “Association between hand grip strength and exercise addiction: differences by sport category and sex among elite athletes.” The original version of this article has been updated.
Open Access: Yes
Demographic Predictors Associated With Elevated Screen Use in Preschoolers: A Multinational Cross-Sectional Study Based on Parents' Reports
Publication Name: Child and Family Social Work
Publication Date: 2026-01-01
Volume: Unknown
Issue: Unknown
Page Range: Unknown
Description:
The widespread use of smartphones and tablets has greatly increased screen exposure among preschoolers. Since early childhood is crucial for cognitive, behavioural and social development, excessive screen time represents a major public health concern. Identifying factors influencing young children's screen use is vital for creating effective family guidance and health policies. Using convenience sampling, this study collected data from 633 parents across 31 countries to examine how family composition, parental and child characteristics affect the screen time of preschoolers (aged 1–5 years). The model, based on Ordinary Least Squares regression, explained 42% of the variance in children's screen time. Parental device-giving frequency emerged as the strongest predictor, with more frequent giving linked to greater exposure. Screen time also increased with child age and the number of children in the family. Children supervised by mothers had significantly less screen time than those supervised by fathers. Parental age, number of adults in the home, child's sex and temperament were not significant predictors. These findings highlight the significant impact of parental behaviour and household dynamics on preschoolers' screen habits. Interventions should directly target these factors, and family screen time guidelines must evolve to reflect the modern technology landscape, promoting balanced and healthy use.
Open Access: Yes
DOI: 10.1111/cfs.70175
Visual assessment of performance-related stimulus expectancy and its implications for placebo response dilution
Publication Name: Acta Psychologica
Publication Date: 2026-05-01
Volume: 265
Issue: Unknown
Page Range: Unknown
Description:
Expectancy effects are crucial determinants of placebo responses; however, neglecting differences in agent-specific beliefs may lead to an underestimation of response effects. This study had two main goals: (1) to theoretically explore how individual differences in expectations about agents influence response outcomes, and (2) to create a visual tool for assessing stimulus-specific expectancies. The sample included 435 adults (58.5% female) who answered demographic questions and completed six image-based items (red pill, white powder, green drink, chocolate bar, injection syringe, and electrical stimulation device), each designed to assess beliefs about the potential of these agents to boost performance. Expectancy assessments focused on anticipated physical and mental performance effects rather than on clinical or therapeutic outcomes. Logistic modeling illustrated that combining high- and low-expectancy individuals can attenuate apparent group-level expectancy effects, highlighting a potential measurement and inference concern in placebo research. Participants who were non-superstitious and non-religious reported significantly lower stimulus expectancy than others. Confirmatory factor analysis (CFA) confirmed the unidimensional structure of the Stimulus Expectancy Assessment Tool (SEAT), showing excellent fit (CFI = 0.974, TLI = 0.952, RMSEA = 0.086, SRMR = 0.032) and good internal consistency (Cronbach's α = 0.84). The latent factor accounted for an average of 48% of the variance in expectations, ranging from 21% to 66% across the six indicators. These results suggest that placebo effects may be underestimated when variability in expectancy is ignored. The SEAT offers a flexible, image-based method for identifying stimulus-specific expectancy profiles.
Open Access: Yes
Genome-Wide Association Study of Vertical Jump Performance Among Elite Badminton Players
Publication Name: International Journal of Molecular Sciences
Publication Date: 2026-03-01
Volume: 27
Issue: 6
Page Range: Unknown
Description:
Vertical jump performance is known to be a moderately heritable trait. However, previous studies on sport genetics have largely relied on candidate-gene approaches, which do not adequately reflect the polygenic nature of explosive performance, particularly among elite badminton players. Therefore, the aim of the present study was to identify genetic variants associated with lower-limb explosive performance, assessed via vertical jump measures, among elite Turkish badminton players using a genome-wide association study (GWAS) approach. The present study included 90 elite male (n = 47) and female (n = 43) badminton players, and 557 non-athletic controls sourced from a public database. Performance-related traits were evaluated through countermovement jump (CMJ), squat jump (SJ), and their differential. Genome-wide genotyping was performed using DNA microarrays, and associations were examined using linear mixed models fixed for sex/gender, body mass index, and sport experience. Although no variants reached genome-wide significance (p < 1.00 × 10−7), 13 single-nucleotide polymorphisms (SNPs) exceeded the suggestive threshold (p < 1.00 × 10−5). CMJ-associated variants were rs4905767, rs2911702, rs10246591, and rs9842454; SJ-associated variants were rs55817650, rs62318127, rs115197840, rs78317172, and rs35930589; and CMJ–SJ-associated variants were rs34638064, rs6679342, rs4931233, and rs9442615. The present study provides preliminary evidence that lower-limb explosive performance among elite badminton players is polygenic, involving regulatory and signaling pathways rather than single performance genes.
Open Access: Yes
DOI: 10.3390/ijms27062533
