Yazar "Souissi, Nizar" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • Küçük Resim Yok
    Öğe
    Acute 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
    (MDPI, 2026) Seddik, Meher; Dhahbi, Wissem; Bessifi, Manel; Moussa-Chamari, Imen; Ceylan, Halil Ibrahim; Ceylan, Nagihan Burcak; 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.
  • Küçük Resim Yok
    Öğe
    Differential Time-of-Day Effects of Caffeine Capsule and Mouth Rinse on Physical Performance and Volleyball-Specific Skills in Adolescent Male Volleyball Players
    (MDPI, 2026) Amor, Salma Belhaj; Dhahbi, Wissem; Souaifi, Marouen; Ceylan, Halil Ibrahim; Padulo, Johnny; Vando, Stefano; 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 & centerdot;kg-1), caffeine mouth rinse (CAFrinse, 3 mg & centerdot;kg-1), and placebo (PLA), administered via a double-dummy procedure (nine sessions per participant: 3 conditions & times; 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 & times; 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 & times; 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.
  • Küçük Resim Yok
    Öğe
    Progressive 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
    (MDPI, 2026) Ben Alaya, Wiem; Dhahbi, Wissem; Souissi, Mohamed Abdelkader; Jebabli, Nidhal; Ceylan, Halil Ibrahim; Ceylan, Nagihan Burcak; 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 & times; group: F(1,28) = 6.84, p = 0.014, eta p2 = 0.20; d = 0.78) and sleep onset latency (F(1,28) = 5.97, p = 0.021, eta p2 = 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, eta p2 = 0.20; d = 0.81) and stress (F(1,28) = 6.45, p = 0.017, eta p2 = 0.19; d = 0.74). Cognitive performance showed significant time & times; group & times; 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.