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Okba Selmi,1,2 Ibrahim Ouergui,1 Danielle E Levitt,3,4 Pantelis T Nikolaidis,5 Beat Knechtle,6 Anissa Bouassida1 1Research Unit, Sportive Performance and Physical Rehabilitation, High Institute of Sports and Physical Education of Kef, University of Jendouba, Kef, Tunisia; 2High Institute of Sports and Physical Education, Ksar Said, University of Manouba, Tunis, Tunisia; 3Applied Physiology Laboratory, University of North Texas, Denton, TX, USA; 4Department of Physiology, School of Medicine, Louisiana State University Health Sciences Center New Orleans, New Orleans, LA, USA; 5Exercise Physiology Laboratory, Nikaia, Greece; 6Institute of Primary Care, University of Zurich, Zurich, SwitzerlandCorrespondence: Beat KnechtleInstitute of Primary Care, University of Zurich Medbase St. Gallen Am Vadianplatz, Vadianstrasse 26, St. Gallen 9001, SwitzerlandTel +41 71 226 93 00Fax +41 71 226 93 01Email beat.knechtle@hispeed.chIntroduction: High-intensity interval training (HIIT) and small-sided games (SSG) have been applied and tested for athletes in order to enhance the soccer performance. For this reason, this experimental study aimed to compare the effects of SSGs and HIIT on power, physiological responses and perceived enjoyment.Materials and Methods: Sixteen youth soccer players (age, 17.5± 0.6 years, mean±standard deviation; height, 178.2± 6.4 cm; body mass, 70.4± 5.4 kg; body fat, 10.6± 0.8%) completed one session each of HIIT and SSG on separate days with 1 week between sessions. Each session lasted 25 mins (4x4 mins work with 3 mins of passive recovery in-between). SSGs consisted of 4 versus 4 player games on a 25× 35 m pitch, and HIIT consisted of intermittent 15-s runs at 110% maximal aerobic speed separated by 15 s of passive recovery. Psychological responses following each protocol were assessed using the Physical Activity Enjoyment Scale (PACES). Heart rate (HR) was continuously recorded, rating of perceived exertion (RPE) and lactate concentration [La] were measured after each training session. Lower body muscular power was assessed using the 5-jump test relative to leg length (5JT-relative) before and after each training session, where greater average distance per stride over five sequential jumping strides indicated greater muscular power.Results: HIIT and SSG showed no significant difference in HR, RPE and [La] responses (p=0.70, ES=0.11; p=0.61, ES=0.08 and p=0.38, ES=0.21, respectively). 5JT-relative decreased significantly for SSG and HIIT (p< 0.05, ES=0.50 and p< 0.05, ES=0.40, respectively). PACES score was greater in SSG compared to HIIT (ES=5.35, p< 0.001).Conclusion: HIIT and SSG sessions induced similar physiological responses; however, SSGs induced a higher enjoyment level than HIIT. Coaches could choose between these training modalities according to the objective of their training session, considering the enjoyment-related advantages of SSGs.Keywords: aerobic fitness, psychology, motivation, soccer, athletes

This study aims to investigate the changes in bioenergetic pathway contributions during repeated sprint exercises with an increasing number of repetitions. Twelve male amateur soccer players executed a single 20 m sprint and three repeated-sprint protocols (5 × 20 m, 10 × 20 m, 15 × 20 m with 15-second rest intervals), analyzing oxidative, glycolytic, and ATP-PCr energy pathways using the PCr-LA-O2 method. Findings revealed a significant decline in energy expenditure and performance outputs as the number of sprint repetitions increased. While the oxidative and ATP-PCr pathways' energy contributions significantly rose with more sprints, the glycolytic pathway's contribution notably increased only up to the 10 × 20 m protocol, then stabilized. Although the ATP-PCr pathway's energy contribution decreased slightly from sprints 1-5 to 11-15, it remained significantly higher than the oxidative and glycolytic pathways throughout. Initially, glycolytic contribution surpassed oxidative in sprints 1-5, equaled it in sprints 6-10, and fell below in sprints 11-15. Glycolytic activity, a major energy source initially (about 36%), diminished substantially with more sprints (below 7% in the 15th sprint). This indicates that the decrease in non-mitochondrial pathway energy, particularly glycolytic, outstrips the aerobic system's increased tolerance. These findings offer physiological insights into the relationship between performance decrement and bioenergetic metabolism in repeated sprints., (© 2024. The Author(s).)

Background: The present study investigated the effect of time of day (08h00 vs. 11h00 vs. 14h00 vs. 17h00) and sex (girls vs. boys) on physical (i.e., five jump test (5JT), push-ball test and 5 m shuttle run test (5mSRT)), cognitive (i.e., attention) and mental (i.e., mental flexibility) performances., Methods: Thirty schoolchildren, equally divided in girls (n = 15; age: 9.60 ± 0.51 years) and boys (n = 15; age: 9.40 ± 0.51 years) performed the digit cancellation test, the trail making test, the 5JT, the 2 kg push-ball test and the 5mSRT in a counterbalanced and cross over study design at 08h00, 11h00, 14h00 and 17h00 with 48 h of rest in between. Additionally, rating of perceived exertion (RPE) was determined after each repetition of the 5mSRT and the average of the score (i.e., sum of RPE scores divided by 6) was determined., Results: Results showed that RPE at the end of the test was significantly higher at 11h00 compared to 08h00 (p = 0.02) and 14h00 (p = 0.001) and average RPE was higher at 11h00 compared to 08h00 (p = 0.001). Likewise, attention was significantly higher at 08h00 compared to 17h00 (p = 0.001) before and after the 5mSRT test only in girls. However, 5JT performance was significantly lower at 17h00, both in girls and boys, compared to at 08h00 (p = 0.02 and p = 0.001 respectively), 11h00 (p = 0.004 and p = 0.001 respectively) and 14h00 (p = 0.001 and p = 0.001 respectively). However, push-ball (p = 0.086) and 5mSRT performances [best distance (p = 0.173), total distance (p = 0.306), mean distance (p = 0.29), fatigue index (p = 0.06)] were time of day independent. Mental flexibility was significantly higher at 08h00, 11h00 and 14h00 compared to 17h00 (p = 0.001)., Conclusion: Mental flexibility, attention and jump performances were time of day dependent and push-ball test and 5mSRT performances did not change according to the time of day. Also, no clear sex effect was found on the diurnal variation of mental, cognitive and physical performances., (© 2024. The Author(s).)

The ATP-PCr system represents the main source of energy during high-intensity attack actions in taekwondo matches. In contrast, the glycolytic system supports the maintenance of these actions when repeated techniques are performed. Given the close relationship between anaerobic energy systems and attack activity in combat, the literature relating to the use of sport-specific test protocols for anaerobic assessment has experienced a remarkable increase. This narrative review aims to illustrate the sport-specific anaerobic tests available in taekwondo by retracing and examining development and validation process for each test. Forty-one articles published between 2014 and 2023 were selected via the MEDLINE and Google Scholar bibliographic databases. These tests are the Taekwondo Anaerobic Test and Adapted Anaerobic Kick Test (i.e., continuous mode testing); the 10 s and multiple Frequency Speed of Kick Tests; the chest and head Taekwondo Anaerobic Intermittent Kick Tests; and the Taekwondo-Specific Aerobic-Anaerobic-Agility test (i.e., intermittent mode testing). Coaches and strength and conditioning professionals can use all the tests described in taekwondo gyms as they feature short and easy-to-implement protocols for monitoring and prescribing specific anaerobic training. The guidelines in this review evaluate each test from several perspectives: basic (e.g., validity, reliability, and sensitivity), methodological (e.g., continuous or intermittent mode testing) and application (e.g., time-motion structure and performance parameters). This comprehensive approach aims to assist stakeholders in selecting the most appropriate test.

The present study compared the isocapnic buffering phase (ICB), hypocapnic hyperventilation phase, ventilatory threshold (VT), respiratory compensation point (RCP), and maximum oxygen uptake (VO 2max ) among biathlon and cross-country ski athletes during an incremental exercise test. 37 male and 33 female Turkish National Team athletes volunteered to participate in the research. Body fat percentage, lean mass, and fat mass values of athletes were measured using the bioelectrical impedance analysis method, and oxygen consumption (VO 2 ) was measured with a portable cardiopulmonary exercise test system with a ramp protocol on the treadmill. In VT, RCP, and VO 2max phases, male athletes had higher VO 2 and speed values than female athletes (p < 0.05). In contrast, they had similar values across different categories of sports (biathlon and cross-country skiing) (p > 0.05). Additionally, XC skiers and males had higher absolute (Abs) VO 2 and mass-normalized (Rel) VO 2 values than biathletes and females in exhaustion times and ICBs (p < 0.05). In contrast, they had similar Abs VO 2 and Rel VO 2 values in hypocapnic hyperventilation phases (p > 0.05). In addition, XC skiers and males had higher absolute (Abs) VO 2 and relative (Rel) VO 2 values than biathletes and females in exhaustion times and ICBs (p < 0.05). In contrast, they had similar Abs VO 2 and Rel VO 2 values in hypocapnic hyperventilation phases (p > 0.05). These results indicate significant differences in physiological profiles between male and female athletes and between XC skiers and biathletes., (© 2024. The Author(s).)

Background: Kickboxing is a popular striking combat sport, and K-1 is a type of kickboxing. Direct head blows can cause significant long-term injury and affect brain wave activity., Objectives: We aim to compare the changes in brain wave activities of fighters during a K-1 kickboxing contest to those in a control group, who were striking a punching bag and were not hit by another K-1 athlete., Methods: A total of 100 professional Polish K-1 kickboxers were split evenly into experimental (n = 50, age 25.5 ± 4.63 years) and control (n = 50, age 26.6 ± 5.22 years) groups. We used quantitative electroencephalography (QEEG) to assess the spectrum of brain wave activity (delta, theta, alpha, sensorimotor rhythm (SMR), beta-1 and beta-2) before and after an intervention (experimental: K-1 contest, control: simulated contest), with eyes open and then closed. The number of direct blows to the head was also recorded for all bouts. Comparative and statistical analyses between selected variables were performed., Results: K-1 fighters showed elevated baseline brain activity for the entire delta band (p < 0.001). There was significant variation in brain activity among the experimental group following the intervention and compared with the control group for all wave types (p < 0.001). No significant variation in activity was found in the control group. The number of direct head blows was positively correlated with brain activity, at delta and beta-2 wave frequencies., Conclusions: K-1 kickboxing is associated with detectable changes in brain wave activity. It is presently unclear what the long-term effects of these changes in brain wave activities are, and longitudinal studies are necessary to study the brain health of kickboxers., (© 2024. The Author(s).)

To assess the effects of warm-up music and low dose (3 mg·kg -1 ) of caffeine (CAF) on female taekwondo athlete's activity profile and psychophysiological responses during simulated combat. In a double-blinded, randomized, crossover study, 16 female athletes participated in simulated combats under one control and 5 experimental conditions [i.e., CAF alone (CAF), placebo alone (PL), CAF with music (CAF + M), PL with music (PL + M), and no supplement with music (M)]. After warming-up, athletes rated their felt arousal (FAS). Mean (HR mean ) and peak (HR peak ) heart rate values were determined for each combat. After fighting, athletes rated their perceived exertion (RPE), feeling scale (FS), FAS, and physical enjoyment (PACES). Time-motion and technical-tactical variables were analyzed. CAF + M induced shorter skip and pause time, while attack time increased compared to other conditions (p < 0.05). Moreover, CAF + M increased single attacks, combined attacks, counter-attacks (p < 0.001), and defensive actions (p < 0.05) than other conditions. HR mean and HR peak were lower under CAF + M than other conditions (p < 0.05). Additionally, higher FAS post-combat, FS, and PACES were observed under CAF + M, while RPE was lower (except CAF condition) compared to the other conditions (p < 0.05.Using CAF with warm-up music may increase combat cadence and improve the psychological state in female athletes more effectively than either strategy alone., (© 2024. The Author(s).)

Purpose: The current study aimed to evaluate the telic-paratelic tendency and heart rate variability in athlete participants from different sports activities. Methods: We assigned 117 healthy participants ( M age = 20, SD = 3 years) into three groups according to their training activity: power-trained (PT; n=43), endurance-trained (ET; n=36), and healthy untrained individuals (n=38). We assessed their telic-paratelic tendencies with the validated Telic Dominance Scale and their autonomic nervous system activity with heart rate variability (HRV) analyses. Results: Our findings revealed no significant differences in the telic-paratelic tendencies between ET and PT groups. However, significant differences were observed between athletes and untrained individuals ( p = 0.001). Indeed, compared to untrained participants, ET and PT athletes had a greater telic tendency (both p = 0.001), were more focused on planning orientation (ET: p = 0.003; PT: p =0.001), and less often avoided arousal or activation (For ET 31% and for PT 26% of participants). The paratelic tendency was more important in untrained individuals, with most of these participants lacking in seriousmindedness and planning. In addition, we found higher HRV in paratelic ET athletes (SDNN p = 0.050, LF p = 0.022, and LF/HF p = 0.031) compared to their telic peers. Conclusion: our results suggest that sport activity did not influence the telic-paratelic tendency. Nevertheless, this tendency differentiates trained from untrained participants. HRV was higher among paratelic ET athletes, potentially reflecting less stress and more training adaptability in these athletes., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. FundingThe author(s) received no financial support for the research, authorship, and/or publication of this article.

Combat sports, encompassing a range of activities from striking and grappling to mixed and weapon-based disciplines, have witnessed a surge in popularity worldwide. These sports are demanding, requiring athletes to harness energy from different metabolic pathways to perform short, high-intensity activities interspersed with periods of lower intensity. While it is established that the anaerobic alactic (ATP-PC) and anaerobic lactic systems are pivotal for high-intensity training sessions typical in combat sports, the precise contribution of these systems, particularly in varied training modalities such as single (SMT) and intermittent (IST) forms of the 30-second Wingate test, remains inadequately explored. This study aims at comparing performance outputs, physiological responses and gender differences during the SMT and IST forms of the 30-second Wingate test. Thirty-three highly trained combat sports athletes (17 women, 16 men; 10 boxing, 8 wrestling, 8 taekwondo and 7 karate) randomly performed SMT and IST. The IST consisted of three 10-second all-out attempts separated by 30 seconds of passive recovery, whereas the SMT was a single 30-second maximal effort. Resting, exercise and post-exercise oxygen uptake and peak blood lactate value were used to determine the metabolic energy demands via the PCr-LA-O2 method. The findings showed that total metabolic energy expenditure (TEE), ATP-PCr system contribution and the output of mechanical variables were higher in the IST than in the SMT form (all p<0.001). In contrast, the contribution of glycolytic and oxidative systems was higher in the SMT form (all p<0.001). However, exercise form and gender interaction were not significant (p>0.05). In combat sports, performance is not only determined by physiological and technical skills but also by metabolic energy input and efficiency. Therefore, our results can provide a comparison regarding the effects of exercise type and gender on metabolic energy metabolism to design the training of combat sports athletes., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Tortu et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Introduction: This investigation aims to elucidate the impact of Ramadan intermittent fasting on performance, physiological responses, and bioenergetic pathway contributions during repeated sprints., Methods: Fourteen active male Muslim athletes (age = 22.4 ± 1.8 years, body weight = 69.5 ± 3.8 kg, height = 176 ± 5.1 cm) executed a repeated sprint protocol, consisting of ten 20-meter sprints with 15-s passive recovery intervals, during both fasting and non-fasting conditions. The fasting session was conducted after a 12-14 h fast following Sahur (the pre-dawn meal during Ramadan). In contrast, the non-fasting session occurred before the Ramadan fasting period began, during the same hours of the day, at a time when fasting was not yet required for the athletes. Bioenergetic pathway contributions during repeated sprints were quantified using the PCr-LA-O 2 method., Results: The mean sprint time during fasting sessions was 3.4 ± 0.3 s compared to 3.3 ± 0.2 s in non-fasting sessions, indicating a trend approaching the threshold of significance for slower times in the fasted state ( p  = 0.052, effect size (ES) = 0.34). In terms of bioenergetic contributions, the total metabolic energy expenditure (TEE) was slightly lower during fasting sessions (236.5 ± 22 kJ) compared to non-fasting sessions (245.2 ± 21.7 kJ), but this difference was not statistically significant ( p  = 0.102, ES = 0.40). Similarly, metabolic energy expenditure per sprint was 23.7 ± 2.2 kJ in fasting conditions compared to 24.5 ± 2.2 kJ in non-fasting conditions ( p  = 0.106, ES = 0.35). The oxidative energy contribution did not differ significantly between fasting (34.2 ± 4.1 kJ) and non-fasting conditions (34.2 ± 4.1 vs. 35.5 ± 5.2 kJ; p  = 0.238, ES = 0.28). Similarly, lactic (60.4 ± 7.6 vs. 59.2 ± 8.3 kJ; p  = 0.484, ES = 0.15); and alactic (149.3 ± 19.9 vs. 143 ± 21.5 kJ; p  = 0.137, ES = 0.30) energy contributions showed no significant differences between the fasting and non-fasting sessions. The percentage of performance decrement (Pdec) and the percentage contributions of oxidative, lactic, and alactic pathways to the total energy expenditure did not differ significantly between the fasting and non-fasting conditions, indicating a similar bioenergetic profile across both conditions., Conclusion: The present findings indicate no significant differences in performance metrics and metabolic outcomes between fasted and non-fasted states. Future assessments with longer duration and higher intensity protocols may provide further insights., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Özbay, Ulupınar, Gençoğlu, Ouergui, Öget, Yılmaz, Kishalı, Kıyıcı, Asan, Uçan and Ardigò.)

Introduction: This study assesses the acute effects of combining a plyometric-based conditioning activity (CA) with different musical stimuli during warm-up on taekwondo (TKD) performance and related psychological aspects., Methods: In a randomized cross-over study design, 16 male TKD athletes (age: 19.94 ± 1.12 years) performed the TKD-specific agility test (TSAT), frequency speed of kick test (FSKT-10s) and its multiple version (FSKT-mult) under 7 experimental and one control condition. For the experimental conditions, participants experienced varying combinations of music selection process [self-selected (SSM) vs. pre-selected (PSM)], and music tempo [fast (F) vs. slow (S)], within preferred (PG) and non-preferred (NPG) music genre; all in the presence of a plyometric based-CA. Athletes were instructed to rate their perceived exertion (RPE) after each test and their felt arousal (FAS), feeling scale (FS), and motivation after testing completion., Results: Findings showed that combining a plyometric-based CA with SSMPG at both fast and slow tempo improved TSAT, FSK-10s, FSKT-mult, FAS, motivation, and RPE post-TSAT greater than the other conditions (all p < 0.05). Additionally, FSSMPG combined with CA improved FS, and RPE after both FSKT-10s and FSKT-mult better than the other conditions (all p < 0.05)., Conclusion: In conclusion, listening to fast self-selected music from a preferred genre in combination with a plyometric-based CA during warm-up setups an individualized warm-up strategy and serves to improve the subsequent specific performances and the related psychological aspects in TKD athletes., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (© 2024 Messaoudi, Ouergui, Delleli, Ballmann, Ardigò and Chtourou.)

Background: Obesity, a common lifestyle-related condition, is correlated with factors like inadequate physical activity. Its connection to diverse health issues presents a significant challenge to healthcare. This pilot study investigated the effects of hypoxic training on aerobic capacity and biometric-structural indicators in obese women. The secondary objective was to determine the feasibility, effectiveness, and safety of the planned research procedures and their potential for larger-scale implementation., Material and Methods: Forty-one non-trained women with first-degree obesity were randomly assigned to even normobaric hypoxic training (H + E), normoxic training (E), passive exposure to hypoxia (H), and a control group (C). Training sessions were conducted three times a week for four weeks (12 training sessions). Body composition parameters were assessed, metabolic thresholds were determined, and maximal oxygen consumption (VO 2 max) was measured before and after interventions., Results: The results demonstrated that training in hypoxic conditions significantly affected somatic parameters, with the H + E group achieving the best outcomes in terms of weight reduction and improvements in body composition indicators ( p < 0.001). Normoxic training also induced a positive impact on body weight and body composition, although the results were less significant compared to the H + E group ( p < 0.001). Additionally, training in hypoxic conditions significantly improved the aerobic capacity among the participants ( p < 0.001). The H + E group achieved the best results in enhancing respiratory endurance and oxygen consumption ( p < 0.001)., Conclusions: The results of this pilot study suggest, that hypoxic training can be effective for weight reduction and improving the aerobic capacity in obese women. Despite study limitations, these findings indicate that hypoxic training could be an innovative approach to address obesity and related conditions. Caution is advised in interpreting the results, considering both the strengths and limitations of the pilot study. Before proceeding to a larger-scale study, the main study should be expanded, including aspects such as dietary control, monitoring physical activity, and biochemical blood analysis.

Modified exercise prescription in judo is commonly used to activate the energy systems in different magnitudes. In order to study the physiological and rating of perceived exertion (RPE) responses according to area sizes (i.e., 4 m × 4 m, 6 m × 6 m and 8 m × 8 m) and training mode variations (i.e., groundwork, ne-waza; standing combat only, tachi-waza; and free combat, free randori), eighteen male judo athletes (age: 22.6 ± 1.8 years) were randomly assigned, on separate days, to 9 experimental conditions (3 area sizes × 3 training modes) with each condition lasting 4 min. Delta lactate [La] was calculated based on the blood lactate values measured before and after every condition. Heart rate (HR) was measured during and after each bout and RPE recorded at the end of each combat. The results showed that mean and peak HR, percentage of maximum HR (% HR max ), delta [La] values and RPE scores were lower in 4 m × 4 m compared to 6 m × 6 m and 8 m × 8 m, and in groundwork training mode compared to standing combat and free randori (all p < 0.001). Furthermore, the 6 m × 6 m condition induced lower delta [La] values than 8 m × 8 m (p < 0.001) and free randori resulted in higher RPE scores than standing combat (p = 0.001). In conclusion, different training variables can be easily manipulated in a variety of different ways to specifically activate the energetic systems. Focusing on groundwork, the 6 m × 6 m area size was found to be the most suitable condition to induce a higher cardiovascular response, while the standing combat and free randori in 6 m × 6 m resulted in increased glycolytic activation compared to the groundwork condition., Competing Interests: All authors declare having no conflict of interest., (Copyright © Biology of Sport 2024.)

This systematic review summarized the studies that examined the pre-task music effects on performance aspects and quantitatively analyzed their outcomes. A systematic search for controlled studies investigating the acute effects of pre-task music on physical performance, cognitive aspects and associated psycho-physiological responses was performed through Scopus, PubMed, Web of Science and Cochrane Library databases up to 17 May 2023, with thirty studies fulfilled the inclusion criteria. Data was analyzed using the robust multilevel meta-analysis model of standardized mean difference "SMD" with 95% confidence intervals (95%CI) and prediction intervals (PI) were reported. Pre-task music induced improvements of completion time (SMD = -0.24; 95% CI = -0.46 to -0.01; PI = -0.82 to 0.35; p  = 0.04), relative mean power (RMP) (SMD = 0.38; 95% CI = 0.16 to 0.60; PI = -0.36 to 1.12; p  = 0.003) and fatigue (SMD = -0.20; 95% CI = -0.32 to -0.09; PI = -0.36 to -0.05; p  = 0.01), moderate effects on relative peak power (RPP) (SMD = 0.53; 95% CI = 0.21 to 0.85; PI = -0.42 to 1.48; p  = 0.005), and high effect on feeling scale (FS) (SMD = 2.42; 95% CI = 0.52 to 4.31; PI = -11.43 to 16.26; p  = 0.03). Greater benefits were recorded in jumping performance in males than females ( p  = 0.01), and for active than trained subjects for completion time ( p  = 0.02), RPP ( p  = 0.02) and RMP ( p  = 0.03). Larger benefits were obtained for FS post-warming up than after testing ( p  = 0.04). Self-selected music induced greater effects than pseudo- and pre-selected for performance decrement index ( p  = 0.05) and FS ( p  = 0.02). It could be concluded that pre-task music improved psychological responses and fatigue-related symptoms associated with exercise performance enhancement., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2023 Delleli, Ouergui, Ballmann, Messaoudi, Trabelsi, Ardigò and Chtourou.)

Under certain circumstances, masks are an effective and immediate solution to reduce the spread of viral infection. However, the impact of masks on the ability to perform vigorous exercise remains an area of concern. Primarily, this impact has been explored in healthy subjects, yielding contradictory findings, and little is known of it among COVID-19-infected individuals. This study examined the effects of surgical masks, N-95 masks, and unmasked conditions on the performance and perceived exertion (RPE) of infected vs. non-infected young women during high-intensity, repeated sprint exercise (5mSRT). Following a familiarization session, eighty-three (42 COVID-19-previously infected (PIG) and 43 non-infected (NIG)), female participants (age 20.02 ± 1.05 years, BMI 21.07 ± 2.1 kg/m 2 ) were randomly assigned to one of three mask conditions: unmasked, surgical mask, or N95 mask. All participants attended three test sessions (i.e., one session for each mask condition) at least one week apart. At the beginning of each test session, data related to participants' physical activity (PA) and sleep behaviours during the previous week were collected. In each test session, participants performed the 5mSRT, during which performance indicators (best distance (BD), total distance (TD), fatigue index (FI) and percentage decrement (PD)) were collected, along with RPE. ANOVA indicated no significant main effects of Groups and Masks, and no significant interaction for Groups × Masks for BD, FI, PD, RPE and most sleep and PA behaviours ( p > 0.05). For TD, the Groups × Mask interaction was significant ( p = 0.031 and ƞp 2 = 0.042). Posthoc analysis revealed, in the unmasked condition, there was no difference in TD between PIG and NIG ( p > 0.05). However, when wearing a surgical mask, PIG covered lower TD compared to NIG ( p < 0.05). Additionally, different types of masks did not affect TD in NIG, while PIG performed the worst using the surgical mask ( p < 0.05). These results suggest post-COVID-19 individuals can maintain physical fitness through regular exercise (i.e., sport science curricula) in unmasked conditions, but not when wearing a surgical mask. Furthermore, the impact of different types of face masks on physical performance seems to be minimal, particularly in uninfected populations; future research is warranted to further explore this impact in post-COVID conditions.

The effects of caffeine (CAF) and music have been well documented when used separately, but their combined effects are not yet studied. Thus, the present study assessed the acute effects of combining a low dose of CAF with listening to music during warm-up on taekwondo physical performance, perceived exertion (RPE), and psychological responses during taekwondo-specific tasks in male elite athletes. In a double-blinded, randomized, placebo-controlled crossover study design, male taekwondo athletes (n = 16; age: 18.25 ± 0.75 years) performed the taekwondo-specific agility test (TSAT), 10 s frequency speed of kick test (FSKT-10s) and the multiple version of FSKT (FSKT-mult) under the following conditions: 1) CAF without music (CAF+NoM), 2) placebo (PL) without music (PL+NoM), 3) CAF with music (CAF+M), 4) PL with music (PL+M), 5) no supplement with music (NoS+M) and no supplement without music (control). RPE, feeling scale (FS), felt arousal scale (FAS) and physical enjoyment (PACES) were determined after each test. Findings showed the CAF+M condition induced better performances than other conditions for TSAT, FSKT-10s, FSKT-mult, RPE, FAS and FS and PACES post FSKT-10s (all p<0.05). Moreover, CAF+M resulted in better responses than other conditions for PACES post TSAT (p<0.05) with the exception of CAF+NoM. Likewise, CAF+M condition induced better physical enjoyment than PL+NoM, NoS+M and PL+M conditions post FSKT-mult (p<0.05). Combining low dose of CAF with music during warm-up was an effective strategy that induced greater effects than their isolated use during taekwondo specific tasks., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Delleli et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Purpose: This study investigated the effects of time-of-day on judo athletes' performances and the associated psychological variables and perceived exertion following judo-specific tests. Methods: Twelve male judo athletes (age: 16 ± 1 years) performed in a randomized and counterbalanced order the special judo fitness test (SJFT), the judo physical fitness test (JPFT), the dynamic and isometric judogi chin-up tests in the morning (8:00 a.m), midday (12:00 p.m), and afternoon (5:00 p.m). Oral temperature and psychological variables [profile of mood state (POMS), Hooper questionnaire, total quality of recovery (TQR)] were assessed before and after the tests, and ratings of perceived exertion (RPE) and the physical activity enjoyment scale (PACES) were assessed only after the tests. Results: RPE score was higher in the morning compared to the afternoon after the JPFT (d = 0.38, p = .045). PACES after JPFT was higher in the morning compared to midday (d = 0.85, p < .001). The isometric and dynamic performances during chin-up tests were higher in the afternoon compared to the morning (d = 0.38, p = .048 and 0.047, respectively). Also, oral temperature was higher in the afternoon compared to the morning (d = 0.41, p = .050) and the midday (p = .047) for dynamic test, while TQR, well-being indices, and POMS did not differ according to time-of-day (p > .05). Conclusions: These results suggest that dynamic and isometric judo chin-up tests are time-of-day dependent with higher performance recorded in the afternoon than in the morning. However, performances in the JPFT and SJFT were not time-of-day dependent.

Purpose: This study investigated the test-retest reliability and discriminant validity of the Kickboxing Anaerobic Speed Test (KAST) and established a comparison with the maximal cycling sprint test (MCST). Methods: Forty-two male kickboxing athletes (18 elite and 24 sub-elite) participated in this study. Kickboxers performed the tests in both single and multiple forms. The KAST single was composed of kicks and punches, performed as quickly as possible until 5 reps of a 4 techniques' combination (i.e., straight left punch, right-roundhouse kick, straight right punch, and left-roundhouse kick) were completed. The MCST single was composed by a single 6-s maximal effort. The KAST multiple was performed using 5 sequential sets of the single form following a 10s rest interval between sets. The MCST multiple was performed using 5 × 6 s repeated cycling efforts with 10s rest intervals. The tests and retests were carried out on separate occasions. To establish the test's discriminatory capability, elite and sub-elite athletes were compared. Results: All tests' performance scores showed excellent relative and absolute reliability (ICC > 0.900, SEM ≤ 0.98 s for KASTs and ≤ 0.74 W•kg -1 for MCST tests). Significant correlations between the identical versions were "large" (r > 0.70). Receiving operating characteristic analyses indicated that the KASTs and cycling tests were able to effectively discriminate between elite and sub-elite kickboxers. Additionally, the findings showed that KAST single , MCST single , KAST multiple , and MCST multiple correctly classified the groups by 78.6%, 73.6%, 88.1%, and 78.6%, respectively. Conclusions: This study supported the test-retest reliability and the discriminant validity of the KAST single and KAST multiple to evaluate kickboxing athletes.

The purpose of this study was to assess the effects of acute caffeine supplementation on physical performance and perceived exertion during taekwondo-specific tasks in male and female athletes with varying expertise. In a double-blinded, randomized, placebo-controlled crossover study design, 52 young athletes from elite (n = 32; 16 males and 16 females) and sub-elite competitive level (n = 20; 10 males and 10 females) participated. Athletes performed taekwondo-specific tasks including the taekwondo-specific agility test (TSAT), 10 s frequency speed of kick test (FSKT-10 s) and multi-bout FSKT (FSKT-multi) under the following conditions: (1) Caffeine (CAF; 3 mg kg -1 ), placebo (PLA), and no supplement control (CON). Session rating of perceived exertion (s-RPE) was determined after the tests. Findings show that regardless of condition, males performed better than females (p < 0.05) and elite athletes had superior performance compared to their sub-elite counterparts (p < 0.05). For the TSAT (p < 0.001), FSKT-10s (p < 0.001), and FSKT-multi (p < 0.001), CAF enhanced performance in elite female athletes compared to sub-elite females. Likewise, CAF ingestion resulted in superior performance in elite males compared to sub-elite males for FSKT-10s (p = 0.003) and FSKT-multi (p < 0.01). The ergogenic potential of CAF during taekwondo-specific tasks appears to be related to a competitive level, with greater benefits in elite than sub-elite athletes., (© 2023. Springer Nature Limited.)

In this study, we aimed to investigate the effects of warm-up music preference and loudness on physical performance, perceived exertion (RPE), and enjoyment in young taekwondo athletes. In a crossover counterbalanced design, 20 taekwondo athletes (10 male, 10 female) performed a battery of physical tasks specific to taekwondo under the following five conditions: (a) No music (NM), (b) Preferred music-Soft (60 dB; PMS), (c) Preferred music-Loud (80 dB; PML), (d) Non-preferred music-Soft (60 dB; NPMS), and (e) Non-preferred music-Loud (80 dB; NPML). On each lab visit, participants completed a taekwondo-specific agility test (TSAT), a10-second kick test (KSKT-10s) and a multiple frequency speed of kick tests (FSKT) within each music condition. Pre-exercise enjoyment was assessed using the Physical Activity Enjoyment Scale (PACES) after the warm-up, while we obtained RPE scores after each test. The PML condition resulted in significantly better agility test times on the TSAT compared to PMS ( p < .001), and NPML ( p < .001). Furthermore, PML led to a greater number of total kicks during the FSKT-10s test compared to the PMS ( p < .001), and NPML ( p < .001) conditions. The decrement index on the FSKT was lower in PML than in PMS and NPML conditions ( p < .001). For RPE, values were significantly lower with preferred than non-preferred music ( p < .001). These findings lend support to ergogenic benefits of listening to PML prior to taekwondo physical tasks, with important implications for enhancing taekwondo training and performance.

Introduction: The present study assessed the effects of conditioning activities, using different effort-to-pause ratios and rest intervals, on taekwondo physical performance. Methods: Twenty-one athletes (13 males and 8 females) (Mean ± SD; age = 20.4 ± 1.4 years) performed a control (CC) and twelve experimental conditions. Each condition contained a standard warm-up (i.e., CC: running at 9 km/h for 10 min) and conditioning activities comprising plyometrics P) or repeated high-intensity techniques (RT) using 1:6, 1:9 and self-selected rest (SSR) ratios, and two rest intervals (3 and 7 min). Athletes then performed a battery of fitness tests: countermovement jump (CMJ), taekwondo specific agility (TSAT), 10s and multiple frequency speed kick test (FSKT-10s and FSKT-mult, respectively). Results: All of the preloads provided higher performance outputs compared to the control trial (all p < 0.05). For CMJ, 1:6 ratio with 3 min induced lower values with RT compared to P ( p = 0.037) and 1:9 ratio using 3 min induced higher values with RT compared to P ( p = 0.027). Additionally, 1:6 ratio using 7 min induced higher values with RT compared to P ( p = 0.016). For FSKT-10, 3 min using 1:6 induced higher values with P compared to RT, while RT induced higher values with 7 min using 1:6 ratio compared to P (both p < 0.001). Moreover, 3 min using 1:9 ratio induced higher values with P compared to RT ( p = 0.034), while RT induced higher values with 1:9 ratio using 7 min compared to P ( p < 0.001). Finally, 3 min using SSR ratio induced higher values with RT compared to P ( p = 0.034). Conclusion: Plyometrics and RT activities improved performance with plyometrics requiring shorter rest interval to induce potentiation effects compared to RT, which required longer interval., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Ouergui, Delleli, Messaoudi, Bridge, Chtourou, Franchini and Ardigò.)

Purpose: This study investigated the effects of 4 weeks of repeated sprint training (RST) versus repeated high-intensity technique training (RTT) on the physiological responses (ie, blood lactate), mean and peak heart rate, rating of perceived exertion, technical-tactical performance, and time-motion variables during simulated taekwondo combats., Methods: Twenty-four taekwondo athletes (18 male and 6 female; age: 16 [1] y) were randomly and equally assigned to RST (10 × 35-m running sprints interspersed by 10-s rest) or RTT (10 × 6-s bandal-tchagui kicking executions interspersed by 10-s rest) groups in addition to their regular training. Both groups performed simulated combats before and after training., Results: Delta lactate and peak heart rate were attenuated following training (P < .001 and P = .03, respectively), with no differences identified between RTT and RST conditions. Rating of perceived exertion decreased after training only in the RTT (P = .002). Time fighting and preparatory activities increased following training (P < .001), with higher values observed following RTT than RST (P < .001). Nonpreparatory time decreased after training (P < .001), with more pronounced reductions observed following RTT when compared to RST (P < .001). The number of single attacks decreased only following RST (P < .001), whereas combined attacks increased only after RTT training (P < .001)., Conclusions: Similar adjustments in the physiological responses to combat were observed following 4 weeks of either RST or RTT, but RTT elicited more favorable perceptual responses and combat-related performance. This highlights the importance of specificity of training and its effective transfer to combat.

The ergogenic effect of pre-selected warm-up music with the tempo and loudness variations on the performance of combat sports' athletes as well as the difference between sexes is not well established. The present study aimed to assess the effects of listening to music with different tempos and loudness during warm-up on perceived exertion, physical enjoyment and physical performances in young taekwondo athletes. In a randomized study design, 20 taekwondo athletes (10 males, mean ± SD: age: 17.5 ± 0.7 years, taekwondo experience: ≥ 6 year) performed the taekwondo specific agility test (TSAT) and the 10s and multiple frequency speed of kick test (FSKT-10s and FSKT-mult) after warming-up with or without music. The music was played at high (140 beats·min-1) or very high (200 beats·min-1) tempo combined with low (60 dB) or high (80 dB) loudness, resulting in four experimental and control conditions. The ratings of perceived exertion (RPE) and physical activity enjoyment scale (PACES) were assessed after each condition. After normality, homogeneity and sphericity checks, two-way (or multivariate) analysis of variance and Bonferrroni (or Friedman's and Wilcoxon's test) post-hoc test were operated when necessary. For TSAT, 140 beats·min-1+80 dB induced better performance compared with 200 beats·min-1+80 dB, 200 beats·min-1+60 dB, control and the 140 beats·min-1+60 dB conditions. For FSKT-10s, 140 beats·min-1+80 dB condition induced higher performance compared with 200 beats·min-1+60 dB, 200 beats·min-1+80 dB, 140 beats·min-1+60 dB and the control conditions. For FSKT-mult, 140 beats·min-1+80 dB induced higher number of techniques compared with 200 beats·min-1+60 dB, 140 beats·min-1+60 dB, control and the 200 beats·min-1+80 dB conditions. Moreover, 140 beats·min-1+80 dB induced lower decrement index (DI) compared with the other conditions and lower DI in 140 beats·min-1+60 dB compared with 200 beats·min-1+80 dB and control conditions. Moreover, 140 beats·min-1+80 dB resulted in greater PACES scores compared with 200 beats·min-1+80 dB and control conditions. Better performance was found for males compared with females in TSAT, FSKT-10s and FSKT-mult (i.e., techniques' number), as well as lower DI and higher RPE post-FSKT-10s. Pre-selected warm-up music played at 140 beats·min-1 and 80 dB is an efficient strategy to enhance physical activity enjoyment and specific performances in taekwondo., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Ouergui et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

(1) Objective: This is a quasi-experimental study that investigated the effect of four weeks of training sessions using video modeling (VM) on individual and collective technical skills in young novice basketball players. (2) Method: 20 players were equally assigned to either a control group (CG, n = 10; 12 ± 0.7 years) or a video modeling group (VMG, n = 10; 12.5 ± 0.5 years; visualizing videos before each session) were assessed before and after the four-week training period using the Basketball Skill Test of the American Alliance for Health, Physical Education, Recreation and Dance for individual techniques and three vs. three small-sided games for collective aspects. (3) Results: For the passing test, VMG induced higher performance than CG ( p = 0.021; d = 0.87). For offensive balls post-intervention, higher values were recorded for VMG compared to CG ( p = 0.003; d = 1.81). In addition, the number of attack balls index post-intervention was higher for VMG compared to CG ( p = 0.001; d = 0.28). For losing the ball, VMG induced lower values than CG after the training intervention ( p < 0.001; d = -3.23). The efficiency index was higher post-training compared to pre-training for VMG ( p = 0.013; d = 1.24). (4) Conclusion: The study highlighted the importance of using video modeling as an effective strategy to improve technical skills and collective performance in novice young basketball players.

Introduction: Psychological aspects of sport are key in maintaining athlete motivation and make a difference in competitive outcomes. Adjustments to training may be necessary according to athletes' emotional state. Therefore, it is important to assess and quantify mood states throughout the season in team sports, including among soccer players. The Profile of Mood States (POMS) is a widely used questionnaire that assesses emotional states characterized by positive or negative feelings and can be administered repeatedly to assess changes in mood state. This review aims to assess and summarize the current literature on mood state variation in soccer players with a specific focus on training loads, training modalities, and competitive performance., Methods: A literature search was systematically conducted and resulted in 156 records. After removing duplicates, items with irrelevant titles and abstracts were screened out, and full texts were then screened for relevance and compared with inclusion and exclusion criteria. The remaining 37 articles were included in the final qualitative synthesis., Results: POMS scores were related to variability in training load, intensity of the training period, modality of training exercises, competitive performance and time of day in soccer players. Common recommendations include monitoring the mood state of soccer players during training sessions, matches, and throughout training periods to detect early signs of psychological disturbance and aid in optimizing high-level training performance., Conclusion: The POMS allows for monitoring of players' psychological state, providing coaches with data to aid in adjusting acute program variables according to players' psychological states and improve performance. Results offer practical support for the use of a simple POMS measurement as part of an overall program to monitor the players' psychological states. Results also highlight how training choices (i.e., load and exercise modality) and competitive performance are related to mood states (i.e., tension, anger, confusion, depression, fatigue, and vigor)., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Selmi, Ouergui, Muscella, Levitt, Suzuki and Bouassida.)

There is evidence for the effectiveness of youth combined plyometric and sprint with change of direction (COD) training. However, the evidence is not well-known regarding the in-season effects of biological age (peak height velocity—PHV) on the motor adaptive processes following combined plyometric and COD with ball training (P-CODBT) in youth soccer players. This study aimed to examine the in-season effects of P-CODBT (8 weeks and twice a week) on the athletic performances of male youth soccer players, circa- and post-PHV. In a randomized controlled training study with pre-to-post measurements, forty-eight male players were assigned into two experimental (performing P-CODBT; n = 12 × circa-PHV and n = 12 × post-PHV) and two control groups (CONG; n = 12 × circa-PHV and n = 12 × post-PHV). The pre- and post-training participants were assessed for their anthropometric, linear sprinting with and without a ball, COD speed with and without a ball, vertical jump, dynamic balance, and endurance-intensive performances. After the intervention, the experimental condition induced significant (all p < 0.0001) and small to large effect size (ES = 0.263−3.471) additional gains only on explosive measures compared to CONG. Both the experimental (all p < 0.0001; ES = 0.338−1.908) and control (p = 0.011−0.0001; ES = 0.2−1.8) groups improved their athletic performances over the training period. The improvements generated by p-CODBT were not affected by biological age. In-season short-term P-CODBT (twice a week) could be safe way to generate benefits in explosive performances in youth soccer players, which are relevant components of match-winning actions in soccer.

While studies on dietary nitrate (NO 3 ) supplementation and its impact on combat sports performance are increasing, finite conclusions from currently available investigations remain unclear. Thus, the present systematic review examined the acute and chronic ergogenic effect(s) of dietary nitrate intake from beetroot on different aspects of combat sports performance. A systematic search for randomized placebo-controlled studies investigating the effects of beetroot supplementation on combat sports outcomes was performed through Scopus, PubMed/MEDLINE, Web of Science, Scielo, Sport Discus, and Cochrane Library databases up to 2 January 2023. The different terms related to beetroot and to combat sports were connected in the search strategies using the Boolean operators 'AND' and 'OR'. A total of nine studies with good methodological quality (based on the Cochrane risk of bias tool) fulfilled the inclusion criteria. Seven studies used an acute supplementation strategy, while the other two studies utilized chronic supplementation. Findings showed beetroot intake may be an effective tool to improve oxidative metabolism and muscle force production (i.e., isokinetic and isometric) in combat sports athletes. However, these effects may depend on the population, intake duration, muscle group activated, and exercise type. Future studies are required to (1) understand the effects on female athletes and (2) elucidate the impacts of dosing protocols and specific exercise modalities for enhancing combat sports performance.- ) supplementation and its impact on combat sports performance are increasing, finite conclusions from currently available investigations remain unclear. Thus, the present systematic review examined the acute and chronic ergogenic effect(s) of dietary nitrate intake from beetroot on different aspects of combat sports performance. A systematic search for randomized placebo-controlled studies investigating the effects of beetroot supplementation on combat sports outcomes was performed through Scopus, PubMed/MEDLINE, Web of Science, Scielo, Sport Discus, and Cochrane Library databases up to 2 January 2023. The different terms related to beetroot and to combat sports were connected in the search strategies using the Boolean operators 'AND' and 'OR'. A total of nine studies with good methodological quality (based on the Cochrane risk of bias tool) fulfilled the inclusion criteria. Seven studies used an acute supplementation strategy, while the other two studies utilized chronic supplementation. Findings showed beetroot intake may be an effective tool to improve oxidative metabolism and muscle force production (i.e., isokinetic and isometric) in combat sports athletes. However, these effects may depend on the population, intake duration, muscle group activated, and exercise type. Future studies are required to (1) understand the effects on female athletes and (2) elucidate the impacts of dosing protocols and specific exercise modalities for enhancing combat sports performance.

During training camps, training load is purposefully intensified. Intensified training loads (TL) are associated with psychological variations, increased fatigue, insufficient recovery, decreased muscular performance, and biological changes in adult athletes, but whether these changes occur during training camps in youth athletes has not been established. The aim of this study was to assess changes in psychometric status, vertical jump performance (i.e., height), and hematological markers before and after an intensive training camp in youth soccer players. In this case, 15male youth soccer players (mean ± SD: age: 14.8 ± 0.4 years; height: 172.0 ± 6.9 cm, body mass: 60.8 ± 7.9 kg; training experience: 5.2 ± 0.7 years) completed a 2-week training program consisting of 1 week of moderate TL (MT) and 1 week of intensive training camp (TC). Rate of perceived exertion (RPE), TL, monotony, strain, and psychometric status (total quality of recovery (TQR) and well-being indices (sleep, stress, fatigue, and muscle soreness) were monitored before each first daily training session across two weeks. The profile of mood states (POMS), countermovement jump (CMJ) height, and blood markers (complete blood count, urea, and creatinine) were assessed before and after TC. TL (d = 5.39, large), monotony (d = 3.03, large), strain (d = 4.38, large), and well-being index (d = 7.5, large) scores increased and TQR (d = 4.6, large) decreased during TC. The TC increased tension, fatigue, and total mood disturbance and decreased vigor (all p <0.01). CMJ performance p < 0.01, d = 0.52, moderate), creatinine (p < 0.01, d = 1.29, large), and leukocyte concentration (p < 0.01, d = 1.4, large) and granulocyte concentration (p < 0.01, d = 1.93, large) increased after TC. Percentage of lymphocytes (p < 0.05, d = 1.17, large) and monocytes (p < 0.01, d = 1.05, large) decreased while the percentage of granulocytes (p < 0.05, d = 0.86, large) increased significantly. Well-being, quality of recovery, mood, granulocyte concentration, and creatinine were all altered during the week-long intensified training camp. These results may provide coaches with valuable information about psychometric status and physiological fatigue and recovery of youth soccer players to better prescribe and adjust training loads during intensive training periods.

Abdominal obesity has emerged globally as a major public health issue due to its high prevalence and morbidity. The benefits of physical exercise among the obese population are well documented. However, the optimal exercise intensity for reducing body fat and preventing insulin resistance and metabolic disorders is still under debate. This study aimed to examine the effects of three different intensities of combined endurance and strength training programs on anthropometric variables, physiological and muscular adaptations, and insulin sensitivity. Forty-three obese young women (age 26.4 ± 4.7 years, BMI 33.1 ± 2.5 kg/m2) were randomly assigned to one of four groups: a control group (G0), a moderate-intensity training group (G50, exercising brisk walking at 50% heart rate reserve HRR), a high-intensity training group (G75, exercise jogging at 75% HRR), and an alternated-intensity training group (G50/75, exercise brisk-walking/jogging at 50−75% HRR) with additional strength training once a week for each group. Body composition, waist circumference (WC), fasting blood glucose, insulin sensitivity and resistance (Homa-IR), resting heart rate (RHR), 6-min walk distance (6MWD), 1-repetition maximum (1-RM), and time to exhaustion (TTE) at 45% and 75% maximal voluntary contraction (MVC) for both the flexor and extensor muscle groups of the knees, were recorded before and after three months of exercise training. All training groups showed significant decreases in body mass, BMI, total body fat, body fat percentage, WC, abdominal and visceral mass (p < 0.001), with a greater reduction of body mass and BMI in G75 (p < 0.05). Lean mass increased significantly only in G50/75 (p < 0.05). The insulin sensitivity and Homa-IR decreased in the three training groups (p < 0.01), with greater enhanced resistance in G50 compared to G75 and G50/75 (p < 0.05). In contrast, there were no pre-post changes in all groups for fasting blood glucose (p > 0.05). 1-RM and TTE of the knee flexor and extensor muscles were improved in the three groups (p < 0.01), with greater improvement in G50/75 for 1RM and G75 in most of the TTE parameters (p < 0.05). RHR decreased and 6MWD increased significantly in the three training groups (p < 0.01), with greater 6MWD improvement in G75 (p < 0.05). In conclusion, the three training intensities seem to generate benefits in terms of body composition, physiological and muscular adaptations, and insulin resistance. High training intensity resulted in greater improvements in body mass, BMI, and endurance and strength, whereas moderate training intensity resulted in greater improvements of insulin resistance and homo-IR. Following alternate-intensity training, greater improvements were observed in lean mass and maximal strength performance.

Short- to middle-term plyometric training has been shown to be an effective method to promote youth fitness and health. However, there is no knowledge of previous studies that investigated the sex and age effects on physical fitness following different PT surfaces (i.e., firm vs. sand) in schoolchildren. This study examined the effects of age and sex on explosive and high-intensity responses following plyometric training (4 weeks, twice/week) performed on firm vs. sand surfaces in untrained schoolchildren. Ninety girls and ninety boys (under 8: age = 7.1 ± 0.5 and 7.1 ± 0.4 years; under 10: age = 9.0 ± 0.4 and 9.0 ± 0.5 years; under 12: age = 11.0 ± 0.5 and 11.0 ± 0.5 years, respectively) participated in a randomized and parallel training design with pre-to-post testing. Participants were allocated (i.e., 30 boys and 30 girls for each group) into either two experimental groups (firm group: performing plyometrics on a clay surface and sand group: performing plyometrics on a dry surface of 20 cm deep sand) or a control group (CG, habitual physical education classes) within their corresponding age groups. Children were tested for sprint, jumping and change of direction speed performances before and after 4 weeks of plyometric training. Both experimental groups induced more significant improvements in all assessed variables than CG (p < 0.0001; effect size > 0.80), whereas both surfaces induced similar improvements (p > 0.05). Older boys achieved better performances than their younger counterparts (p < 0.05) and older girls (p < 0.0001), respectively. This finding showed that age and sex could affect explosive and high-intensity performances during childhood after a short-term plyometric training. In contrast, the training-induced fitness changes were not influenced by the type of surface.

This study aimed to investigate the changes in internal training intensity, well-being, and countermovement jump (CMJ) performance and to determine their relationship across five weeks of the pre-season training phase in professional soccer players. A total of 22 professional male soccer players (age = 21.7 ± 4 years, body height = 185.9 ± 6.3 cm, body weight = 79 ± 6.3 kg, BMI = 22.8 ± 1.4 kg·m−2; VO2max = 52.9 ± 3.2) from the Croatian Second League voluntary participated in this study. The players spent 2230 ± 117 min in 32 technical/tactical and strength/conditioning training sessions, mostly at the low intensity zone (61%), and played 8 friendly matches at a high intensity (>90%). A one-way repeated measure of analysis ANOVA revealed a significant difference between weeks in CMJ performance (F(1,22) = 11.8, p < 0.001), with CMJ height in weeks 4 and 5 being likely to very likely higher than that noted in week 1. Moreover, significant differences between weeks were found in all internal training intensity measures (average [F(1,22) = 74.8, p < 0.001] and accumulated weekly internal training intensity [F(1,22) = 55.4, p < 0.001], training monotony [F(1,22) = 23.9, p < 0.001], and training strain [F(1,22) = 34.5, p < 0.001]). Likewise, differences were observed for wellness status categories (fatigue [F(1,22) = 4.3, p = 0.003], sleep [F(1,22) = 7.1, p < 0.001], DOMS [F(1,22) = 5.7, p < 0.001], stress [F(1,22) = 15.6, p < 0.001]), mood [F(1,22) = 12.7, p < 0.001], and overall well-being status score (F(1,22) = 13.2, p < 0.001). Correlation analysis showed large negative correlations between average weekly internal training intensity and fatigue (r = −0.63, p = 0.002), DOMS (r = −0.61, p = 0.003), and WBI (r = −0.53, p = 0.011). Additionally, fatigue was significantly associated (large negative correlation) with accumulated weekly internal training intensity (r = −0.51, p = 0.014) and training strain (r = −0.61, p = 0.003). Small, but non-significant, correlations were found between CMJ performance and wellness status measures. These findings highlight the utility and simplicity of monitoring tools to improve athletes’ performance.

This study investigated the effects of intensified training and tapering periods using different exercise modalities on judo athletes' physical fitness. Fifty-nine adolescent male and female judo athletes (age 15 ± 1 years) were randomly assigned to one of three experimental groups or one control group (CG). Experimental groups (kumi-kata [KG], uchi-komi [UG] and running [RG]) trained four times per week over four weeks of intensified training (in addition to their usual technical-tactical judo training; CG underwent only the usual training) followed by 12 days of tapering. The countermovement jump test (CMJ), isometric and dynamic judogi chin-up tests (JCT), uchi-komi speed test (UST), Special Judo Fitness Test (SJFT) and Judo Physical Fitness Test (JPFT) were administered before and after the intensified period and after tapering. The CMJ performance was superior in KG compared with UG, RG and CG. Isometric JCT performance was superior in KG compared with RG and CG. Regarding UST, performance was superior in UG compared with RG and CG. The same performance was superior with respect to the same groups considering pre-training to tapering change. The SJFT index did not differ between groups or time-points. The JPFT index increased after intensified and tapering periods compared with before training, with KG eliciting higher values compared with CG. Coaches and conditioning coaches could administer kumi-kata high-intensity interval training to enhance athletes' judo-specific physical fitness., Competing Interests: The authors declare that they do not have any conflict of interest., (Copyright © Biology of Sport 2022.)

In order to maximize adaptations and to avoid nonfunctional overreaching syndrome or noncontact injury, coaches in high-performance sports must regularly monitor recovery before and after competitions/important training sessions and maintain well-being status. Therefore, quantifying and evaluating psychometric states of recovery during the season in sports teams such as soccer is important. Over the last years, there has been substantial growth in research related to psychometric states of recovery in soccer. The increase in research on this topic is coincident with the increase in popularity obtained by subjective monitoring of the pre-fatigue state of the players before each training sessions or match with a strong emphasis on the effects of well-being or recovery state. Among the subjective methods for players' control, the Hooper index (HI) assesses the quality of sleep during the previous night, overall stress, fatigue, and delayed-onset muscle soreness. Additionally, the total quality of recovery (TQR) scale measures recovery status. The HI and TQR recorded before each training session or match were affected by the variability of training load (TL) and influenced the physical and technical performances, and the affective aspects of soccer players. Researchers have recommended wellness monitoring soccer players' psychometric state of recovery before each training session or match in order to detect early signs of fatigue and optimize high-level training performance. This method allows for better detecting signs of individual fatigue and allows coaches to adapt and readjust the TL, and avoid physical and technical gaps in order to improve the performance of soccer players.

Although the effects of caffeine supplementation on combat sports performance have been extensively investigated, there is currently no consensus regarding its ergogenic benefits.This systematic review with meta-analysis aimed to summarize the studies investigating the effects of caffeine supplementation on different aspects of performance in combat sports and to quantitatively analyze the results of these studies to better understand the ergogenic effect of caffeine on combat sports outcomes. A systematic search for randomized placebo-controlled studies investigating the effects of caffeine supplementation on combat sports' performance was performed through Scopus, Pubmed, Web of Science and Cochrane Library databases up to 18 April 2022. Random-effects meta-analyses of standardized mean differences (Hedge's g) were performed to analyze the data. Twenty-six studies of good and excellent methodological quality (based on the Pedro scale) fulfilled the inclusion criteria. The meta-analysis results revealed caffeine has a small but evident effect size (ES) on handgrip strength (ES = 0.28; 95% CI: 0.04 to 0.52; p = 0.02), and total number of throws during the special judo fitness test (SJFT) (ES = 0.42; 95% CI: 0.06 to 0.78; p = 0.02). Regarding the physiological responses, caffeine increased blood lactate concentration ([La]) in anaerobic exercise (ES = 1.23; 95% CI: 0.29 to 2.18; p = 0.01) and simulated combat (ES = 0.91; 95% CI: 0.34 to 1.47; p = 0.002). For Heart Rate (HR), caffeine increased HR final (ES = 0.31; 95% CI: 0.11 to 0.52; p = 0.003), and HR 1min (ES = 0.20; 95% CI 0.004 to 0.40; p = 0.045). However, caffeine had no impact on the countermovement jump height, the SJFT index, the judogi strength-endurance test, the number and duration of offensive actions, HR at the end of the fight, and the rating of perceived exertion. Caffeine supplementation may be ergogenic for a range of combat sports aspects involving isometric strength, anaerobic power, reaction time, and anaerobic metabolism. However, supplementation effects might be ineffective under certain circumstances, indicating supplementation needs to take into account the performance metric in question prior to creating a dosing protocol.

Background: In combat sports, successful competition and training require comprehensive motor fitness. The aim of this study was to diagnose the level of physical fitness and to determine the level of differences between athletes of combat sports characterized by stand-up fighting, such as Muay Thai; and ground fighting, such as Brazilian jiu-jitsu., Methods: The study examined and compared 30 participants divided into two equal groups: Muay Thai athletes ( n = 15; age: 24.24 ± 3.24; body height: 174.91 ± 5.19; body weight: 77.56 ± 7.3), and Brazilian jiu-jitsu (BJJ) ( n = 15; age: 22.82 ± 1.81; body height: 175.72 ± 7.03; body weight: 77.11 ± 8.12). Basic characteristics of the somatic build were measured. Selected manifestations of the motor potential of motor skills were also evaluated using selected tests from the EUROFIT test battery, the International Test of Physical Fitness, and computer tests of coordination skills. Relative strength and maximal anaerobic work (MAW) indices were calculated. The strength of the relationship between the effect of motor fitness and training experience was also assessed., Results: The athletes of both groups (Muay Thai and BJJ) presented similar levels of basic characteristics of the somatic build. Motor fitness in the tested groups showed significant differences between the athletes of these sports in static strength ( p = 0.010), relative strength ( p = 0.006), arm muscle strength in pull-ups ( p = 0.035), and functional strength in bent arm hanging ( p = 0.023). Higher levels of these components of motor fitness were found for the athletes in the BJJ athletes. In the Muay Thai group, significant very high strength of association was found between training experience and five strength tests. Furthermore, a significantly high strength of association was found in two tests. In the BJJ group, significant relationships with very high correlation were found between the variables in five strength tests., Conclusions: Brazilian jiu-jitsu athletes performed better in strength tests (static strength, relative strength, shoulder girdle strength, functional strength). High correlations between the training load and the level of physical fitness were found in flexibility and strength tests in BJJ athletes and most strength tests in Muay Thai athletes.

Plyometric training (PT) has been found to be effective for children’s fitness. However, no study has examined the effects of sex on physical fitness adaptations from surface-type PT in children. This study compared the effects of short-term surface-type PT (firm vs. sand) on the physical fitness of schoolchildren of both sexes. Sixty girls (age = 10.00 ± 1.15 years) and sixty boys (age = 10.02 ± 1.12 years) participated in a short-term (4 weeks), randomized and parallel PT design with pre-to-post measurements. Children were divided into two experimental groups (firm group: PT performed on a clay surface, 20 boys and 20 girls; sand group: PT performed on a dry surface of 20 cm deep sand, 20 boys and 20 girls) and a control group (CG, 20 boys and 20 girls). Squat jump, standing long jump, 20 m sprint, 5-10-5 shuttle, dynamic balance, and maximal aerobic velocity were measured at baseline and after intervention. Both experimental groups showed greater pre-post changes in all assessed variables than the CG (p < 0.0001). No significant differences in pre-post changes were observed relative to surface type or sex (p > 0.05). These findings suggest that a twice-weekly PT program induced physical fitness improvements, which may have transfer to health status during childhood. Additionally, surface type and sex did not affect the training-induced changes in physical fitness.

This study investigated the combined effects of competition area (4 × 4, 6 × 6, and 8 × 8 m) and judo-specific training type (tachi-waza, ne-waza, and free randori) on physiological responses and perceived exertion in female judo athletes. In a within-subject design, 12 female subelite and elite athletes who competed at regional or national levels with a mean training background of 8.4 ± 0.5 years performed the experimental conditions (i.e., combats (viz., matches) featuring different area/training type combinations) in random order. The following measurements at different time points were chosen: blood lactate before and after each match; heart rate before, mean, and peak for each match; and rating of perceived exertion immediately after each match. Two-factor analysis of variance was used to compare between conditions, while Bonferroni post hoc test and magnitude of difference were used to measure significance. There was no main effect of training type or area size on lactate before each match, heart rate (HR) before each match, HR mean during each match, and rating of perceived exertion. Main effects of training type and area size were found for lactate after each event, with the values being greater in free randori compared to tachi-waza and ne-waza and in 4 × 4 m compared to 6 × 6 and 8 × 8 m area. Main effects of training type and area size were also found in peak heart rate, with lower values in ne-waza compared to free randori and tachi-waza and in 8 × 8 m compared to 4 × 4 m area. The results demonstrate that varying training modality and area size may alter physiological responses during female judo combats by putting stress on the cardiovascular system and increasing anaerobic glycolysis solicitation.

The study examined the relationship between psychometric status, neuromuscular, and biochemical markers of fatigue in response to an intensified training (IT) period in soccer. Fifteen professional soccer players volunteered to participate in the study (mean ± SD: age: 25 ± 1 years; body height: 179 ± 7 cm, body mass: 73.7 ± 16.2 kg, experience: 13.2 ± 3 years). Training load, monotony, strain, Hooper index and total quality recovery (TQR) were determined for each training session during a 2-week of IT. Counter-movement jump (CMJ) and biochemical responses [testosterone, cortisol, testosterone-to-cortisol ratio (T/C ratio), creatine kinase, and C-reactive protein] were collected before and after IT. Results showed that IT induced significant increases in cortisol, creatine kinase and C-reactive protein and significant decreases in T/C ratio and CMJ performance from before to after IT (p < 0.01, p < 0.001, p < 0.001, p < 0.01, p < 0.05, respectively). However, testosterone did not differ from before to after IT (p > 0.05). Training loads were positively correlated with Hooper index (p < 0.05) and negatively correlated with total quality recovery (p < 0.05). Hooper index was positively correlated with cortisol (p < 0.05), T/C ratio (p < 0.01), and creatine kinase (p < 0.01), and negatively correlated with CMJ (p < 0.05). Furthermore, TQR was negatively correlated with T/C ratio (p < 0.01), creatine kinase (p < 0.001), and C-reactive protein (p < 0.05), and positively correlated with CMJ (p < 0.01). Neuromuscular fatigue, muscle damage, and change in the anabolic/catabolic state induced by the IT were related to well-being and perceived recovery state among professional soccer players., Competing Interests: The authors declare that they have no conflict of interest., (Copyright © Biology of Sport 2021.)

The general and sports psychology research is limited regarding the difference between the effects of verbal encouragement (VE) or compliment methods during high-intensity functional exercise testing. The purpose of this study was to explore the effects of VE and compliments on the performance of the repeated change-of-direction (RCOD) sprint test. A total of 36 male students in secondary school participated voluntarily in the study. They were divided equally into three homogeneous groups [VE group, compliment group (CG), and control group) and performed a standardized one repetition RCOD. The RCOD (6 × 20 m with 25-s active recovery) test consisted of a 100°change in the direction at every 4 m. Outcomes included performance indices (fast time, average time, and total time), rating of perceived exertion (RPE), and feeling scale scores. VE and the compliment increased the performance indices and RPE compared with the control group. In conclusion, VE during the exercise testing would be more beneficial for optimal performance and RPE compared with the compliment and control groups. However, the moods, during RCOD, reproduce more positively during compliment conditions than the VE and control groups., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Sahli, Haddad, Jebabli, Sahli, Ouergui, Ouerghi, Bragazzi and Zghibi.)

The study assessed conditioning activities' (CAs') effects involving different work-to-rest ratios (WRR) on taekwondo athletes' physical performance. Adolescent taekwondo athletes (age: 16 ± 1 years) randomly participated in the control six experimental conditions. Each condition was composed of standard warm-up and CA composed of plyometrics (P) or repeated high-intensity techniques (RHIT) performed using three different WRR: 1:6, 1:7, self-selected rest time (SSRT). After rest, athletes performed countermovement jump (CMJ), taekwondo specific agility test (TSAT), 10 s frequency speed kick test (FSKT-10s), multiple frequency speed kick test (FSKT-mult). P1:7, SSRT induced techniques higher number in FSKT-10s ( p < 0.001 for all comparisons) and lower TSAT time ( p < 0.01 for all comparisons) compared with control. Kicks-number recorded during FSKT-mult was lower in the control compared with RHIT1:6 ( p = 0.001), RHIT1:7 ( p < 0.001), RHITSSRT ( p < 0.05), P1:7 ( p < 0.001), and SSRT ( p < 0.001). Kicking decrement index (DI) during FSKT-mult was lower after RHIT1:6 compared with control ( p = 0.008), RHIT1:7 ( p = 0.031), P 1:6 ( p = 0.014), PSSRT ( p = 0.041). (1) P1:7 and PSSRT can be used to improve taekwondo-specific agility and kicks-number, (2) RHIT1:6 is beneficial to maintain low DI, and (3) plyometric and different WRR-repeated-techniques can enhance kicks-number.

This study investigated low-dose caffeine ingestion, conditioning activity (CA) effects on psycho-physical performances in young taekwondo athletes. In a randomized, double-blind, counterbalanced, crossover design, 20 athletes (10 males; 17.5 ± 0.7 yrs) performed taekwondo-specific agility test (TSAT), 10 s/multiple frequency speed of kick test (FSKT-10s/FSKT-mult) after ingesting 3 mg·kg−1 caffeine (CAF) or placebo (PL) 60 min before performing standard warm-up without (NoCA) or with CA (3 × 10 vertical jumps above 40 cm), resulting in four experimental (PL + NoCA, CAF + NoCA, PL + CA, and CAF + CA) and one control (warm-up session without CAF or CA) conditions. Mood/physical symptoms (MPSS), subjective vitality (SVS), and feeling (FS) scales were analyzed post-to-pre for all conditions. Ratings of perceived-exertion and perceived-recovery status were determined after tests. For TSAT, CAF + CA induced better performance compared with all conditions (p < 0.001). For FSKT-10s and FSKT-mult, CAF + CA induced better performance compared with all conditions (p < 0.001). For MPSS, FS, CAF + NoCA induced higher scores than PL + NoCA and PL + CA (p = 0.002, 0.009 for MPSS; p = 0.014, 0.03 for FS). For SVS, PL + CA elicited lower scores than PL + NoCA and CAF + NoCA (p = 0.01, 0.004). Sex comparisons resulted in better performances for males for TSAT (p = 0.008), FSKT-10s (p < 0.001), FSKT-mult (p < 0.01), MPSS (p = 0.02), SVS (p = 0.028), and FS (p = 0.020) scores. Caffeine and conditioning activity are two efficient performance-enhancing strategies, which could synergistically result in greater psycho-physical performances.

Background: To handle the competition demands, sparring drills are used for specific technical-tactical training as well as physical-physiological conditioning in combat sports. While the effects of different area sizes and number of within-round sparring partners on physiological and perceptive responses in combats sports were examined in previous studies, technical and tactical aspects were not investigated. This study investigated the effect of different within-round sparring partners number (i.e., at a time; 1 vs. 1, 1 vs. 2, and 1 vs. 4) and area sizes (2 m × 2 m, 4 m × 4 m, and 6 m × 6 m) variation on the technical-tactical aspects of small combat games in kickboxing., Method: Twenty male kickboxers (mean ± standard deviation, age: 20.3 ± 0.9 years), regularly competing in regional and national events randomly performed nine different kickboxing combats, lasting 2 min each. All combats were video recorded and analyzed using the software Dartfish., Results: Results showed that the total number of punches was significantly higher in 1 versus 4 compared with 1 versus 1 (p = 0.011, d = 0.83). Further, the total number of kicks was significantly higher in 1 versus 4 compared with 1 versus 1 and 1 versus 2 (p < 0.001; d = 0.99 and d = 0.83, respectively). Moreover, the total number of kick combinations was significantly higher in 1 versus 4 compared with 1 versus 1 and 1 versus 2 (p < 0.001; d = 1.05 and d = 0.95, respectively). The same outcome was significantly lower in 2 m × 2 m compared with 4 m × 4 m and 6 m × 6 m areas (p = 0.010 and d = - 0.45; p < 0.001 and d = - 0.6, respectively). The number of block-and-parry was significantly higher in 1 versus 4 compared with 1 versus 1 (p < 0.001, d = 1.45) and 1 versus 2 (p = 0.046, d = 0.61) and in 2 m × 2 m compared with 4 m × 4 m and 6 × 6 m areas (p < 0.001; d = 0.47 and d = 0.66, respectively). Backwards lean actions occurred more often in 2 m × 2 m compared with 4 m × 4 m (p = 0.009, d = 0.53) and 6 m × 6 m (p = 0.003, d = 0.60). However, the number of foot defenses was significantly lower in 2 m × 2 m compared with 6 m × 6 m (p < 0.001, d = 1.04) and 4 m × 4 m (p = 0.004, d = 0.63). Additionally, the number of clinches was significantly higher in 1 versus 1 compared with 1 versus 2 (p = 0.002, d = 0.7) and 1 versus 4 (p = 0.034, d = 0.45)., Conclusions: This study provides practical insights into how to manipulate within-round sparring partners' number and/or area size to train specific kickboxing technical-tactical fundamentals., Trial Registration: This study does not report results related to health care interventions using human participants and therefore it was not prospectively registered., (© 2021. The Author(s).)