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- MakaleAçık Erişim2026Scopus SJRQ3Mindfulness-Acceptance-Commitment Intervention Effects on Athletic Performance, Passion, and Psychological Well-being in Competitive Tennis Players: A Randomized Controlled Trial
Abidi, Wafa; Fall, Estelle; Chalghaf, Nasr; Ceylan, Halil İbrahim; Muntean, Raul Ioan; Dergaa, Ismail; Candar, Reyhan; Özdemir, Kübra; Çingöz, Yunus Emre; Man, Cristina Maria
While traditional psychological skills training focuses on cognitive control, mindfulness-based approaches emphasize acceptance and present-moment awareness. The Mindfulness-Acceptance-Commitment (MAC) protocol shows promise for enhancing athletic performance; however, limited research has examined its effects on passion and well-being in tennis players. Forty-four competitive male tennis players (M age = 18.1 ± 1.1 years) were randomly assigned to either a MAC intervention group (n = 22) or a passive control group (n = 22). The MAC protocol consisted of seven weekly 45-minute sessions focusing on mindfulness, acceptance, and values-driven behavior. Primary outcomes included tennis serve performance assessed by certified coaches using a standardized 16-serve protocol. Secondary outcomes included mindfulness skills (Mindful Attention Awareness Scale), subjective well-being (Positive and Negative Affect Schedule, Satisfaction with Life Scale), harmonious passion, and obsessive passion (Passion Scale). Intention-to-treat analyses with 44 participants revealed significant improvements in the MAC group compared to controls. Tennis serve performance improved significantly in the MAC group (pre: 13.18 ± 2.19 to post: 15.09 ± 2.45, t(21) = 7.54, p < .001, d = 0.87) but not in the control group (pre: 13.05 ± 2.33 to post: 12.86 ± 2.41, t(21) = 0.78, p = .442, d = 0.08), with a significant between-group difference at post-test (t(42) = 3.71, p = .001, d = 1.12). Mindfulness skills improved substantially in the MAC group (pre: 39.00 ± 4.18 to post: 52.73 ± 3.65, t(21) = 13.76, p < .001, d = 3.28) compared to controls (pre: 43.55 ± 4.75 to post: 44.32 ± 4.12, t(21) = 1.31, p = .203, d = 0.16), with a significant between-group difference (t(42) = 7.16, p < .001, d = 2.16). Harmonious passion increased significantly in the MAC group (pre: 17.27 ± 2.64 to post: 24.05 ± 4.16, t(21) = 6.15, p < .001, d = 2.57) while remaining stable in controls (pre: 17.86 ± 3.75 to post: 16.91 ± 3.61, t(21) = 1.65, p = .114, d = 0.25), with a significant between-group difference (t(42) = 6.40, p < .001, d = 1.93). Obsessive passion decreased in the MAC group (pre: 23.73 ± 3.66 to post: 16.27 ± 2.86, t(21) = 7.54, p < .001, d = 2.04) while remaining unchanged in controls (pre: 18.00 ± 3.85 to post: 18.41 ± 4.04, t(21) = 0.85, p = .406, d = 0.11), with a significant between-group difference (t(42) =-2.02, p = .050, d =-0.61). Subjective well-being improved markedly in the MAC group (pre: 9.00 ± 7.37 to post: 27.09 ± 7.47, t(21) = 8.37, p < .001, d = 2.45) compared to controls (pre: 4.54 ± 5.85 to post: 8.72 ± 6.08, t(21) = 0.65, p = .526, d = 0.71), with a significant between-group difference (t(42) = 6.85, p < .001, d = 2.07). MAC training represents an effective intervention for enhancing tennis performance, psychological well-being, and adaptive passion while reducing maladaptive passion. These findings support the clinical utility of mindfulness-based approaches in tennis psychology and warrant further investigation on a larger scale.
- MakaleAçık Erişim2026Scopus SJRQ1Differential Time-of-Day Effects of Caffeine Capsule and Mouth Rinse on Physical Performance and Volleyball-Specific Skills in Adolescent Male Volleyball Players
Amor, Salma Belhaj; Dhahbi, Wissem; Souaifi, Marouen; Ceylan, Halil İbrahim; Padulo, Johnny; Vando, Stefano; Ceylan, Nagihan Burçak; Muntean, Raul Ioan; Souissi, Nizar
Objective: This study compared the acute effects of caffeine capsule ingestion and caffeine mouth rinsing on physical performance and volleyball-specific skills at different times of day in trained adolescent male volleyball players. Methods: Twenty-four well-trained male volleyball players (age: 16.9 ± 0.7 years) completed a randomized, double-blind, placebo-controlled crossover study involving three supplementation conditions, caffeine capsule (CAFcap, 3 mg·kg−1), caffeine mouth rinse (CAFrinse, 3 mg·kg−1), and placebo (PLA), administered via a double-dummy procedure (nine sessions per participant: 3 conditions × 3 times of day) at 08:00, 12:00, and 18:00. Participants completed squat jump (SJ), countermovement jump (CMJ), block jump, attack jump, 10 × 10 m t-test, spike accuracy, and serve accuracy assessments. Data were analyzed using two-way repeated-measures ANOVA. Results: Significant main effects of condition and time of day were observed for all outcomes. Significant condition × time-of-day interactions were found for SJ, CMJ, attack jump, and change-of-direction speed, indicating that caffeine-related ergogenic effects were most evident in the morning and at midday, whereas these benefits were attenuated in the evening when baseline performance was highest. At 08:00 and 12:00, both CAFcap and CAFrinse improved jump performance and agility compared with PLA, with capsule ingestion showing a small-to-moderate advantage over mouth rinsing for selected lower-limb power outcomes at midday (mean difference range: 0.51–0.57 cm; dz = 0.57–0.65). For block jump, spike accuracy, and serve accuracy, both caffeine conditions improved performance relative to placebo, while a progressive improvement across the day was observed under all conditions, including placebo, confirming a diurnal rhythm effect independent of supplementation. Overall, the data indicate that caffeine partially reduced the amplitude of diurnal variation in several physical performance measures. Conclusions: Both caffeine capsule ingestion and caffeine mouth rinsing enhanced physical and volleyball-specific performance in trained adolescent male volleyball players. The ergogenic effects were more pronounced earlier in the day, suggesting that caffeine may be particularly useful for attenuating morning and midday performance decrements, while mouth rinsing represents a practical non-ingestive alternative with meaningful efficacy.
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- MakaleAçık Erişim2026Scopus SJRQ1Progressive Smartphone Restriction Combined with Psychoeducational Guidance and Pre-Sleep Autonomic Regulation Improves Sleep Efficiency and Time-of-Day Cognitive Performance in Physically Active Students with Nomophobia: A Randomized Controlled Trial
Alaya, Wiem Ben; Dhahbi, Wissem; Souissi, Mohamed Abdelkader; Jebabli, Nidhal; Ceylan, Halil İbrahim; Ceylan, Nagihan Burçak; Muntean, Raul Ioan; Souissi, Nizar
Aim: This study compared the effects of standard evening smartphone restriction with an adapted intervention combining progressive restriction, psychoeducational guidance, and pre-sleep relaxation on sleep, psychological state, cognitive performance, and physical performance in physically active physical education students with moderate-to-high nomophobia. Methods: Thirty participants (age 21.9 ± 1.2 years; intermediate chronotype) completed a randomized controlled trial consisting of a 7-day baseline period, a 14-day intervention phase, and post-intervention assessments. The standard group (n = 15) implemented a 2-h pre-bedtime smartphone restriction combined with general sleep hygiene guidance. The adapted group (n = 15) followed a progressive restriction protocol (30→60→120 min) supplemented with psychoeducational guidance targeting smartphone-related anxiety and a nightly slow-paced breathing routine. Objective sleep parameters were quantified using wrist-worn actigraphy. Subjective sleep quality, pre-sleep anxiety, and stress were assessed using visual analog scales. Cognitive performance (psychomotor vigilance task and choice reaction time) and physical performance (vertical jumps and agility) were evaluated at both morning and afternoon time points. Results: The adapted intervention produced significantly greater improvements in sleep efficiency (time × group: F(1,28) = 6.84, p = 0.014, ηp2 = 0.20; d = 0.78) and sleep onset latency (F(1,28) = 5.97, p = 0.021, ηp2 = 0.18; d = 0.72) compared with standard restriction. Significant reductions were also observed in pre-sleep anxiety (F(1,28) = 7.12, p = 0.012, ηp2 = 0.20; d = 0.81) and stress (F(1,28) = 6.45, p = 0.017, ηp2 = 0.19; d = 0.74). Cognitive performance showed significant time × group × time-of-day interactions, with improvements during afternoon assessments in psychomotor vigilance (F(1,28) = 7.48, p = 0.011; d = 0.83) and choice reaction time (F(1,28) = 6.89, p = 0.014; d = 0.79) exclusively in the adapted group. Physical performance outcomes remained stable across interventions. Conclusions: Progressive smartphone restriction combined with psychoeducational strategies and pre-sleep relaxation yields clinically meaningful improvements in sleep continuity, psychological arousal, and afternoon cognitive performance, exceeding the benefits achieved through behavioral restriction alone.
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- MakaleAçık Erişim2026Scopus SJRQ3Ramadan intermittent fasting alters cardiac autonomic modulation, neuromuscular performance, and recovery in adolescent tennis players: a within-subject repeated-measures design
Lakhdar, Nadia; Landolsi, Mounir; Ghouili, Hatem; Ceylan, Halil Ibrahim; Ceylan, Nagihan Burcak; Muntean, Raul Ioan; Alsaeed, Mohammed Issa; Ben Said, Noureddine M.; Zaouali, Monia; Bouhlel, Ezzedine
Background: Tennis requires repeated high-intensity efforts with brief recovery periods, placing significant demands on cardiac autonomic regulation and neuromuscular performance. Ramadan intermittent fasting alters sleep, nutrition, and hydration patterns, potentially affecting match responses, particularly in adolescents. Methods: Sixteen male International Tennis Federation (ITF) junior players completed a within-subject repeated-measures study during mid-Ramadan and 15 days post-Ramadan. Each performed a standardized two-set outdoor match under both conditions. Heart rate variability (HRV), countermovement jump (CMJ), blood glucose, hydration markers, and rating of perceived exertion were assessed at baseline (T0), between sets (T1), and post-match (T2). Sleepiness, chronotype, fatigue, and recovery were evaluated via validated questionnaires. Results: Match play reduced lnRMSSD (p < 0.001, eta p(2 )= 0.775) and increased LF/HF (p < 0.001, eta p(2)= 0.234), indicating sympathetic dominance. During Ramadan, parasympathetic activity was lower (p < 0.001, eta p(2)= 0.269), and CMJ performance was reduced (p = 0.010, eta p(2)= 0.085). Blood glucose showed a Period & times; Set interaction (p = 0.020,eta p(2) = 0.114). Sleepiness, fatigue, and perceived recovery were significantly impaired (p < 0.001). Conclusion: Ramadan intermittent fasting reduces vagal activity and impairs neuromuscular performance in adolescent tennis players. HRV-guided training, optimized nutrition, and sleep management may help mitigate these effects.
- MakaleAçık Erişim2026Scopus SJRQ1Acute Caffeine Ingestion, Calendar-Based Menstrual-Cycle Window, Time of Day, and Match-Induced Fatigue Independently and Interactively Influence Psychophysiological, Cognitive, and Physical Performance in Elite Female Volleyball Players: A Randomized Double-Blind Placebo-Controlled Crossover Design Study
Seddik, Meher; Dhahbi, Wissem; Bessifi, Manel; Moussa-Chamari, Imen; Ceylan, Halil Ibrahim; Ceylan, Nagihan Burcak; Muntean, Raul Ioan; Cular, Drazen; Souissi, Nizar
Aim: Female athletic performance is shaped by the convergence of menstrual-cycle timing, circadian rhythms, fatigue, and ergogenic supplementation; yet no prior study has examined these factors simultaneously in a sport-specific setting. This study investigated the independent and combined effects of acute caffeine ingestion, calendar-based testing window, time of day, and match-induced fatigue on psychophysiological, cognitive, and physical performance in trained female volleyball players. Methods: Thirteen elite eumenorrheic female volleyball players (age: 24.23 +/- 4.06 years) completed a randomized, double-blind, placebo-controlled crossover protocol comprising 12 sessions corresponding to all combinations of testing window (menstrual, follicular, luteal), supplementation (caffeine 6 mg & centerdot;kg(-1) vs. placebo), and time of day (08:00 h vs. 18:00 h). Assessments included the Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, Spiegel questionnaire, Profile of Mood States, Hooper Index, Stroop task, Countermovement Jump (CMJ), Modified Agility T-Test (MAT), and Reactive Agility Test (RAT), administered before and after a one-hour simulated match. Results: Significant main effects of testing window, caffeine, time of day, and fatigue state were observed across all outcome domains (all p < 0.05). Caffeine reduced daytime sleepiness (F(1,12) = 23.84, p < 0.001, eta p(2) = 0.665), enhanced vigor (F(1,12) = 114.10, p < 0.001, eta p(2) = 0.905), and improved MAT performance (F(1,12) = 33.27, p < 0.001, eta p(2) = 0.735). The follicular window was associated with superior cognitive, neuromuscular, and mood-related outcomes relative to the menstrual and luteal windows. Exploratory higher-order interactions suggested condition-specific caffeine benefits for MAT, RAT, and CMJ, particularly in afternoon post-fatigue conditions; these patterns require replication in larger samples. Conclusions: Acute caffeine ingestion improved several psychophysiological, cognitive, and neuromuscular outcomes in trained female volleyball players, with effects that varied across calendar-based testing windows, time of day, and fatigue state. Individualized supplementation strategies incorporating cycle timing and circadian context remain investigational; prescriptive recommendations require replication in larger, hormonally verified samples before clinical or applied adoption.
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- MakaleAçık Erişim2025Scopus SJRQ1Casein Supplementation Timing and Exercise Performance in Soccer Players: Pre-Sleep vs. Post-Exercise Intake—A Randomized Controlled Trial
Bayrakdaroğlu, Serdar; Ateş, Zeynep Hazal; Ceylan, Halil İbrahim; Kul, Murat; Muntean, Raul Ioan; Dhahbi, Wissem
Background: Nutrient timing strategies may influence recovery and performance in athletes; however, the effects of ingesting casein protein before sleep versus immediately after exercise remain unclear. This study compared the acute effects of pre-sleep and post-exercise ingestion of casein on high-intensity anaerobic performance in highly trained soccer players. Methods: Twenty-four highly trained male soccer players (mean age: 20.6 ± 1.8 years) were randomly assigned to three groups: post-exercise casein ingestion group (PECIG; n = 8), pre-sleep casein ingestion group (PSCIG; n = 8), and control group (CG; n = 8). Following a standardized high-intensity resistance training protocol, participants consumed 30 g of micellar casein dissolved in 300 mL of water either immediately after exercise or 30–60 min before bedtime. Performance was assessed using the Countermovement Jump (CMJ), the Illinois Agility Test (IAT), and the Running-based Anaerobic Sprint Test (RAST), which were conducted both before and 24 h after the training session. Results: Repeated-measures ANOVA revealed significant group-by-time effects for CMJ (F = 8.21, p = 0.002, η2p = 0.36) and RAST performance variables, including peak power (F = 6.94, p = 0.003, η2p = 0.32), mean power (F = 7.42, p = 0.002, η2p = 0.34), and fatigue index (F = 5.87, p = 0.008, η2p = 0.28). Post hoc analyses showed that PSCIG significantly improved CMJ (Δ = +1.45 cm; p < 0.001, d = 2.04) and RAST mean power (Δ = +125.14 W; p = 0.002, d = 1.55) compared with the control condition. PECIG significantly enhanced RAST peak power (Δ = +205.79 W; p = 0.001, d = 1.64), mean power (Δ = +128.43 W; p = 0.013, d = 1.24), and fatigue index (Δ = +4.12 W/s; p = 0.010, d = 1.29) relative to CG. No performance differences were observed between PSCIG and PECIG timing conditions (all p > 0.05). Conclusions: Both pre-sleep and post-exercise casein ingestion enhanced anaerobic performance in highly trained soccer players, with each timing method favoring different performance outcomes. However, neither strategy demonstrated superiority over the other, suggesting that casein timing may be flexibly applied according to athletes’ preferences and training contexts.
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