Analysis of Sports Supplement Consumption of Elite Referees of the Spanish Professional Fotball League.

BACKGROUND: Sports supplements (SSs) are widely used among team sport athletes; however, evidence supporting the use of SSs among football referees at the elite level is scarce. The aim of the present study was to analyze the consumption of SSs among referees with respect to their level of competition and referee type (main referees (MRs) vs. assistant referees (ARs)). METHODS: A total of 106 football referees participated in this study, with 46.2% from the First Spanish Division and 53.8% from the Second Spanish Division, representing 84.13% of the total number of referees. Each participant completed a validated questionnaire about SS consumption, with the SSs classified according to the Australian Institute of Sport (AIS) ABCD system: Group A has strong evidence for enhancing athlete health and performance, Group B shows potential benefits but needs more evidence, Group C has inconclusive evidence against use, and Group D includes prohibited substances. RESULTS: A total of 84.0% of the MRs and ARs reported the consumption of at least one SS. Differences were found only in the consumption of medical supplements between division (p = 0.016) and type of referee (p = 0.041), though no significant differences were found among the remaining AIS SS categories (p > 0.05). Sport performance (49.6%), Internet (41.0%), and dietitian-nutritionists (31.7%) were the primary reason for SS consumption, purchase location, and source of information, respectively. The most frequently consumed SS were whey protein (45.3%), followed by creatine (33.0%), sport bars and sports drinks (28.3%), and caffeine (19.8%). CONCLUSIONS: MRs and ARs reported a high prevalence of dietary supplement (SS) consumption, with significant differences between division and referee type observed only in medical supplement consumption.

Locomotor and Physiological Demands of Small-Sided Soccer Games in Wildcard and Regular Players: Effects of Goalkeepers and Type of Wildcard.

BACKGROUND: Small-sided games (SSGs) are frequent training drills in soccer. This study investigated whether type of game (ie, with/without goalkeepers) and wildcard ( without vs internal vs external wildcard) impact the physiological (heartrate [HR]) and locomotor (total distance [TD] covered) demands in regular and wildcard players and to evaluate between-player and within-player variability. HYPOTHESIS: Demands are influenced by wildcard and game type, with higher demand (distance covered at high intensities and sprint speed) in regular players and with higher variability in SSG with wildcard players. STUDY DESIGN: Descriptive/comparative study. LEVEL OF EVIDENCE: Level 4. METHODS: Twenty-four soccer players completed 6 SSG as 3 versus 3 without (NG) or with (GK) goalkeepers, and with internal (NG+IW and GK+IW) and external (NG+EW and GK+EW) wildcard. Average HR (HRavg), rate of perceived exertion, and locomotor demands (TD, medium [MID = 7.0-13.9 km h-1], high [HID = 14.0-20.9 km h-1] and sprint [SPD >21.0 km h-1] distance and peak speed [PS]) were registered. RESULTS: The inclusion of GK and internal wildcard led to decreased HRavg and TD in regular players. Wildcard players positioned internally exhibited higher TD, PS, and lower HRavg than externally positioned wildcards. Regular players demonstrated higher TD, PS, MID, HID, HRavg and time spent in Z3 (>90% HRmax) compared with wildcard players in SSG played with external wildcard. Regular and wildcard players displayed great between- and within-player variability in high-intensity metrics. CONCLUSION: Specific game type and wildcard inclusion impact the physiological and locomotor demands in SSG, with variations observed between regular and wildcard players. CLINICAL RELEVANCE: This study provides comprehensive information on the physiological and locomotor demands of SSG depending on the inclusion and position of goalkeepers and wildcards, which can be useful for strength and conditioning coaches when designing specific training tasks, individualizing training load and applying return-to-play programs.

Impacto de ejercicios bilaterales y unilaterales en la potenciación aguda del salto horizontal en futbolistas profesionales / Impact of Bilateral and Unilateral Exercises on Acute Enhancement of Horizontal Jump Performance in Professional Soccer Player / Impacto dos Exercícios Bilaterais e Unilaterais no Aumento Agudo do Desempenho do Salto Horizontal em Jogadores Profissionais de Futebol

Resumen Objetivo: Analizar el efecto de una activación realizada a través de ejercicios de fuerza y pliometría ejecutados de forma bilateral o unilateral sobre el rendimiento en salto horizontal. Metodología: En el estudio participaron 15 futbolistas masculinos, altamente entrenados (edad, 24.7 ± 3.1 años; altura, 181.2 ± 4.7 cm; peso, 79.7 ± 3.4 kg) pertenecientes al mismo equipo, que competía en liga nacional. Su rutina de entrenamiento regular constaba de 4 sesiones y 1 partido competitivo por semana. Los participantes llevaron a cabo 1 protocolo control (CON) y 3 protocolos de activación, siguiendo un diseño contrabalanceado, basados en ejercicios específicos de fútbol (SIN), ejercicios de fuerza y pliometría ejecutados de forma bilateral (BIL) y unilateral (UNI). Después de cada protocolo los jugadores realizaron la prueba de salto horizontal (HZB). Resultados: Los resultados de la prueba ANOVA de medidas repetidas mostraron efectos positivos significativos sobre el HZB de los protocolos SIN (p<0.01; dif = 2.95(2.00)%), BIL (p<0.01; dif = 3.22(2.61) %); y UNI (p<0.01; dif = 6.80(3.40) %) con respecto a CON. Además, HZB fue, significativamente, mayor después del protocolo UNI que del SIN (p<0.01; dif = 3.74(2.62) %) y BIL (p<0.01; dif = 3.47(1.94) %). El análisis de la respuesta individual reflejó efectos positivos en HZB de los protocolos SIN, BIL y UNI respecto al CON, mientras que el 89 % de los jugadores tuvieron mejor rendimiento en HZB después de UNI que de BIL. Conclusiones: Una activación que incorpora estímulos de fuerza y pliometría ejecutados, de forma unilateral, tiene un efecto positivo mayor sobre la capacidad de salto horizontal, que una activación que involucra ejercicios generales, específicos de fútbol y de ejecución bilateral.

Abstract Objective: To analyze the effect of activation through bilateral or unilateral strength and plyometric exercises on horizontal jump performance. Methodology: The study involved 15 highly trained male soccer players (age, 24.7 ± 3.1 years; height, 181.2 ± 4.7 cm; weight, 79.7 ± 3.4 kg) from the same team competing in the national league. Their regular training routine consisted of 4 sessions and 1 competitive match per week. Participants performed 1 control protocol (CON) and 3 activation protocols following a counterbalanced design based on specific soccer exercises (SIN), bilateral (BIL), and unilateral (UNI) strength and plyometric exercises. After each protocol, players underwent the horizontal jump test (HZB). Results: The repeated measures ANOVA revealed significant positive effects on HZB for the SIN (p<0.01; diff = 2.95(2.00) %), BIL (p<0.01; diff = 3.22(2.61) %), and UNI (p<0.01; diff = 6.80(3.40) %) protocols compared to CON. Furthermore, HZB was significantly higher after the UNI protocol than after SIN (p<0.01; diff = 3.74(2.62) %) and BIL (p<0.01; diff = 3.47(1.94) %). Individual response analysis reflected positive effects on HZB for SIN, BIL, and UNI compared to CON, while 89 % of players showed better HZB performance after UNI than after BIL. Conclusions: Activation incorporating unilateral strength and plyometric stimuli has a greater positive effect on horizontal jump capacity than activation involving general, soccer-specific, and bilateral exercises.

Resumo Objetivo: Analisar o efeito da ativação por meio de exercícios de força e pliométricos bilaterais ou unilaterais no desempenho do salto horizontal. Metodologia: O estudo envolveu 15 jogadores de futebol masculinos altamente treinados (idade, 24.7 ± 3.1 anos; altura, 181.2 ± 4.7 cm; peso, 79.7 ± 3.4 kg) da mesma equipe competindo na liga nacional. Sua rotina de treinamento regular consistia em 4 sessões e 1 jogo competitivo por semana. Os participantes realizaram 1 protocolo de controle (CON) e 3 protocolos de ativação seguindo um desenho contrabalanceado com base em exercícios específicos de futebol (SIN), exercícios de força e pliométricos bilaterais (BIL) e unilaterais (UNI). Após cada protocolo, os jogadores foram submetidos ao teste de salto horizontal (HZB). Resultados: A ANOVA de medidas repetidas revelou efeitos positivos significativos no HZB para os protocolos SIN (p<0.01; diff = 2.95(2.00) %), BIL (p<0.01; diff = 3.22(2.61) %) e UNI (p<0.01; diff = 6.80(3.40) %) em comparação com CON. Além disso, o HZB foi significativamente maior após o protocolo UNI do que após SIN (p<0.01; diff = 3.74(2.62) %) e BIL (p<0.01; diff = 3.47(1.94) %). A análise de resposta individual refletiu efeitos positivos no HZB para SIN, BIL e UNI em comparação com CON, enquanto 89 % dos jogadores mostraram melhor desempenho de HZB após UNI do que após BIL. Conclusões: A ativação incorporando estímulos de força e pliométricos unilaterais tem um efeito positivo maior na capacidade de salto horizontal do que a ativação envolvendo exercícios gerais, específicos do futebol e bilaterais.

Plyometric Jump Training Effects on Maximal Strength in Soccer Players: A Systematic Review with Meta-analysis of Randomized-Controlled Studies.

BACKGROUND: Maximal strength may contribute to soccer players' performance. Several resistance training modalities offer the potential to improve maximal strength. During recent years, a large number of plyometric jump training (PJT) studies showed evidence for maximal strength improvements in soccer players. However, a comprehensive summary of the available data is lacking. OBJECTIVE: To examine the effects of PJT compared with active, passive or intervention controls on the maximal strength of soccer players, irrespective of age, sex or competitive level. METHODS: To perform a systematic review with meta-analysis following PRISMA 2020. Three electronic databases (PubMed, Web of Science, and SCOPUS) were systematically searched. Studies published from inception until March 2023 were included. A PICOS approach was used to rate studies for eligibility. The PEDro scale was used to assess risk of bias. Meta-analyses were performed using the DerSimonian and Laird random-effects model if ≥ 3 studies were available. Moderator and sensitivity analyses were performed, and meta-regression was conducted when ≥ 10 studies were available for a given comparison. We rated the certainty of evidence using GRADE. RESULTS: The search identified 13,029 documents, and from these 30 studies were eligible for the systematic review, and 27 for the meta-analyses. Overall, 1,274 soccer players aged 10.7-25.0 years participated in the included studies. Only one study recruited females. The PJT interventions lasted between 5 and 40 weeks (median = 8 weeks), with 1-3 weekly sessions. Compared to controls, PJT improved maximal dynamic strength (18 studies, 632 participants [7 females], aged 12.7-24.5 y; effect size [ES] = 0.43, 95% confidence interval [CI] = 0.08-0.78, p = 0.017, impact of statistical heterogeneity [I2] = 77.9%), isometric strength (7 studies; 245 participants, males, aged 11.1-22.5 y; ES = 0.58, 95% CI = 0.28-0.87, p < 0.001, I2 = 17.7%), and isokinetic peak torque (5 studies; 183 participants, males, aged 12.6-25.0 y; ES = 0.51, 95% CI = 0.22-0.80, p = 0.001, I2 = 0.0%). The PJT-induced maximal dynamic strength changes were independent of participants' age (median = 18.0 y), weeks of intervention (median = 8 weeks), and total number of training sessions (median = 16 sessions). The certainty of evidence was considered low to very low for the main analyses. CONCLUSIONS: Interventions involving PJT are more effective to improve maximal strength in soccer players compared to control conditions involving traditional sport-specific training. Trial Registration The trial registration protocol was published on the Open Science Framework (OSF) platform in December 2022, with the following links to the project ( https://osf.io/rpxjk ) and to the registration ( https://osf.io/3ruyj ).

A Global Positioning System Used to Monitor the Physical Performance of Elite Beach Handball Referees in a Spanish Championship.

Beach handball is a fully developed sporting discipline on all five continents which has attracted the attention of researchers in the last decade, resulting in a proliferation of different studies focusing on players but not on referees. The main objective of this cross-sectional research was to determine the physical demands on elite male beach handball referees in four different competitions: U18 male; U18 female; senior male; and senior female. Twelve elite federated male referees (age: 30.86 ± 8 years; body height: 175.72 ± 4.51 cm; body weight: 80.18 ± 17.99 kg; fat percentage: 20.1 ± 4.41%; national or international experience) belonging to the Technical Committee of the Royal Spanish Handball Federation were recruited for this the study. The physical demands required of referees in official matches were measured by installing a GPS device. The sampling frequency used to record their speed and distance was 15 Hz. A triaxial accelerometer (100 Hz) was used to determine their acceleration. An analysis of variance (ANOVA) between competitions with post hoc comparisons using the Bonferroni adjustment was used to compare among categories. A higher distance covered in zone 1 and speeds of 0 to 6 km-h-1 were recorded. Most accelerations and decelerations occurred in zones 0 and 1 (zone 0: 0 to 1 m·s-2; zone 1: 1 to 2 m·s-2). The lack of differences (p > 0.05) between most analysed variables suggest quite similar physical demands of the four analysed competitions. These results provide relevant information to design optimal training plans oriented to the real physical demands on referees in an official competition.

The Inclusion of Preplanned and Random and Unanticipated/Unexpected Events During Strength Training Improves the Ability to Repeat High-Intensity Efforts Under Uncertainty.

PURPOSE: To compare the effects of unilateral flywheel training (FT), using a rotational conical pulley, including multidirectional movements with either preplanned or random unanticipated/unexpected executions on functional performance in football players. METHODS: A total of 32 young male football players were randomly assigned to an FT program including preplanned unilateral multidirectional movements (PTG, n = 11), an FT executing the same unilateral movements through random (ie, right or left leg) unanticipated (ie, verbal or visual cue) or unexpected (ie, moment where the cue was provided) situations (UTG, n = 11), or a control group (n = 10) that followed their football training routine. FT consisted of 1 set × 5-12 repetitions of 4 exercises performed once a week for 10 weeks. Intermittent endurance performance, repeated unilateral and bilateral jumping ability, change-of-direction (COD) ability, linear sprint velocity, preplanned repeated-sprint ability (RSA), and uncertainty RSA (RSA-RANDOM) were assessed preintervention and postintervention. RESULTS: Significant improvements were found in RSA-RANDOM performance (P < .05, effect size [ES] range: UTG [1.83-2.16], PTG [0.69-0.73]) and COD (P < .05, ES: UTG = 1.34, PTG = 0.98]) in both training groups. Furthermore, significant improvements were also found in intermittent endurance performance (P = .016, ES = 0.37) and sprinting (P = .006, ES = 0.45) in UTG. No changes in any variable were found in the control group. No significant between-groups differences (P > .05) were reported between UTG and PTG, while differences were observed to the control group in unilateral jumping ability, COD, and RSA-RANDOM for UTG, and in RSA-RANDOM for PTG. CONCLUSIONS: A 10-week unilateral FT improved RSA-RANDOM and COD ability in youth football players, so both preplanned and unexpected situations should be included on strength training.

Physical Demands in the Worst-Case Scenarios of Elite Futsal Referees Using a Local Positioning System.

The aim of this study is to analyze the worst-case scenarios of professional futsal referees during the first and second half of official matches in the Spanish Futsal Cup using a Local Positioning System (LPS) for monitoring their movement patterns. Eight professional futsal referees (40 ± 3.43 years; 1.80 ± 0.03 m; 72.84 ± 4.01 kg) participated in the study. The external load (total distance, high-speed running distance and efforts, sprint distance and efforts, and accelerations and decelerations distances) of the referees was monitored and collected using an LPS. The results revealed significant differences in the worst-case scenarios of the futsal referees during the match according to the time window analyzed (p < 0.05). The longest time windows (120 s, 180 s, and 300 s) showed lower relative total distances in the worst-case scenarios (p < 0.05). The high-speed running distances were significatively higher in the first half for the 120 s (+2.65 m·min-1; ES: 1.25), 180 s (+1.55 m·min-1; ES: 1.28), and 300 s (+0.95 m·min-1; ES: 1.14) time windows (p < 0.05). No differences were found between the first and second half for the high-intensity deceleration distance (p > 0.05). These results will serve to prepare the referees in the best conditions for the competition and adapt the training plans to the worst-case scenarios.

Association between physical demands, skin temperature and wellbeing status in elite football players.

The demanding nature of elite football requires players to be closely monitored to ensure optimal performance and minimize injury risk. This study aimed to evaluate the relationship between physical demands, skin temperature, and well-being status in 30 elite football players over a 12-week competitive period. Thermography assessments, weekly Well-being questionnaires, and daily training and match load recordings were used to gather data. Results indicated that along the microcycles there was a decrease in high-intensity accelerations and decelerations distance completed, while maintaining other high-intensity actions. Furthermore, it was found that high-intensity movements contribute to the generation of thermal asymmetries in the thighs; the adductor thermal asymmetry showed a positive relationship with stress and muscle soreness, the knee thermal asymmetry had a positive relationship with fatigue and a negative relationship with rest and quality of rest, and finally the hamstrings muscles exhibited significant differences between the thermal asymmetry groups, with the high asymmetry completing less high intensity actions than the low asymmetry group. In conclusion, this study highlights the interconnections between physical demands, skin temperature, and well-being in elite football players and provides valuable insights for coaches and trainers in their efforts to optimize performance and health.

Study the Effect of an Innovative Educational Program Promoting Healthy Food Habits on Eating Disorders, Mediterranean Diet Adherence and Body Composition in University Students.

The university stage is a good time to promote healthy eating strategies. The sociological and cultural changes experienced by students lead them to skip meals, increase their intake of fast food and energy-dense foods, decreasing adherence to the Mediterranean diet (MD). Professionals related to food such as nutritionists and dietitians are also considered a population at risk of developing eating disorders due to the extensive knowledge they possess, which can be used for both good and bad practice. The objective was to analyze the impact of a 4-month educational program promoting the Mediterranean diet on risky eating behaviors, adherence to the Mediterranean diet, and body composition in nutrition and dietetics students, studying the differences according to the group investigated (control group and educated group). The context of the research was 196 students (49 males and 147 females) from two consecutive years. The control group did not receive any type of intervention, while with the control group (educated) an educational program was carried out. Results showed that women with greater control over energy intake, carbohydrates, and sugar had a lower percentage of fat mass, while in men, the relationship was established with weight. Regarding adherence to the Mediterranean diet, at post, it is adequate in both men (8.25 ± 2.87) and women (7.90 ± 2.89), with no significant differences between the intervention groups.

Relationship between Repeated Sprint Ability, Countermovement Jump and Thermography in Elite Football Players.

Football is a very demanding sport which requires players to exert maximum effort, producing fatigue and eventually injuries. Thermography can be used to detect fatigue and prevent its consequences through thermal asymmetries in the bilateral body areas; however, its adequacy for elite footballers has not been widely studied. Therefore, the objective of the present investigation was to determine the suitability of thermography to detect fatigue in male football players. For this reason, twenty participants were gathered into a pair of subgroups (low [<0.2 °C] vs. high thermal asymmetry [≥0.2 °C]) based on a thermography session of the lower limbs (thighs, calves, and hamstrings). After the thermography session, players performed CMJs before and after an RSA test (6 × 30 m/20″). A mixed two-way analysis of variance and Bonferroni post hoc pairwise comparisons were undertaken to analyse the results. No significant differences (p > 0.05) were found in any of the RSA test variables between low and high thermal asymmetry groups for thighs and calves. On the other hand, the low thermal asymmetry hamstring group reported a smaller percentage difference in sprints for the first sprint (%Diff) and a larger percentage difference in sprints two and three with respect to the best sprint (%Best). For CMJs, the low thermal asymmetry hamstring group reported significantly higher values post-RSA test, indicating better performance. Accordingly, thermography can provide information about performance in CMJ and RSA tests through hamstring asymmetries over 0.2 °C. Meanwhile, larger asymmetries than 0.2 °C in calves and thighs do not seem to be related to performance in these tests; therefore, coaches should consider if it is optimal to align players with high hamstring asymmetries.

The effects of training based on Nordic hamstring and sprint exercises on measures of physical fitness and hamstring injury prevention in U19 male soccer players.

This study analysed the effects of a training program based on Nordic hamstring and sprint exercises on physical performance and hamstring injuries in young male soccer players. Forty-nine U19 players were randomly assigned to a control (CG; n = 26) or experimental group (EG; n = 23). Linear sprint and with change of direction (COD) were assessed before and after a 14-week training period. Hamstring injuries were collected during the intervention period. Between-groups analysis revealed differences in linear sprint performance (p = 0.012-0.001) in favour of the EG. Pre-to-post performance increased significantly in the EG for 20 m (effect size [ES] = -0.56) and 30 m (ES = -0.62) sprints, but a significant reduction in some COD parameters was observed (ES = 0.45-0.57). In CG, only a significant reduction in COD with dominant leg was found (ES = 0.63). Significant differences in injury burden in favour of the EG was reported such as (27.87 [CG] vs. 3.82 [EG] absence days/1000 h of exposure, rate ratio = 7.30, 95% CI 3.34-15.99). While injury incidence was not different between the EG and CG. These findings suggest that the training program implemented can improve sprint performance and reduce injury burden.

Physical demands on professional Spanish football referees during matches.

BACKGROUND: Refereeing is a demanding and intermittent activity that combines high-speed and low-intensity action. OBJECTIVE: The aim of this study is to analyse the external and internal load of professional Spanish football referees during matches, and to compare the physical demands between halves and between referees in different categories. METHODS: The physical demands on 40 professional football referees from the first and second divisions were recorded using global positioning system (GPS) technology and heart rate bands. External load (distance covered, speed, acceleration and deceleration) and internal load (perceived exertion [RPE] and heart rate [HR]) were analysed. RESULTS: The referees in the first division reported lower mean HR and RPE results than those in the second division (p < 0.05). The total distance covered was similar between the categories (p > 0.05), but the distance covered at different speed ranges was different (p < 0.05). Finally, greater reductions in performance between the first and the second halves were found in the second division referees (p < 0.05). CONCLUSIONS: The results of this study show differences according to the category of referee. This emphasises the need for specific training for professional referees according to their level to ensure optimal performance during matches.

Effect of the Length of the Microcycle on the Daily External Load, Fatigue, Sleep Quality, Stress, and Muscle Soreness of Professional Soccer Players: A Full-Season Study.

BACKGROUND: The aim of this study was to analyze the effect of the length of the microcycle (ie, training period from the day after the match to the following match) on the daily external load and perceived wellness of professional soccer players (Spanish LaLiga Smartbank). HYPOTHESIS: The length of the microcycle has a significant effect on the daily external load and perceived wellness. STUDY DESIGN: Longitudinal study. LEVEL OF EVIDENCE: Level 3. METHODS: Data were collected daily during a full season using perceived wellness questionnaires and electronic performance and tracking systems. RESULTS: The length of the microcycle had a significant effect on volume- and intensity-related external load variables. There were differences between short, regular, and long microcycles depending on the day of the microcycle. These differences were observed in all external load variables. However, no significant differences between short, regular, or long microcycles were found on match day for any external load variable, except for high-intensity decelerations. Regarding the perceived wellness, the length of the microcycle had no effect on these variables, and there were no significant interactions between the length and the day of the microcycle. CONCLUSION: The length of the microcycle had a significant effect on volume- and intensity-related external load variables, but no significant effect on perceived wellness was observed. CLINICAL RELEVANCE: These data may help strength and conditioning coaches understand that workload periodization should take this contextual variable into account, especially for external training load. In addition, this study may serve as a guide for practitioners to know the physical requirements of professional soccer players in Spanish LaLiga Smartbank, because the weekly external load profile and perceived wellness have been reported for different lengths of the microcycles. Thus, these data may be used for player load management.

Effects of body mass-based resistance training on measures of physical fitness and musculotendinous injury incidence and burden in U16 male soccer players.

This study examined the effects of body mass-based resistance training (bmRT) on selected measures of physical fitness and injury incidence and burden in soccer players. Forty-six U16 male soccer players were randomly assigned to an control (CG; n = 26) or experimental group (EG; n = 20) Countermovement jump (CMJ), change of direction (CoD) (i.e., 20 m with one CoD), and linear sprint over 30 m were assessed before and after a 15-weeks training. Any type of musculotendinous injury that occurred throughout the intervention period was recorded. Between-group difference was noted at post-test for CMJ (p = 0.008). Pre-to-post training values increased in the EG (effect size [ES] = 1.01) while in the CG no pre-to-post changes were detected (ES = 0.27). No between-group differences at post-test were observed for sprint and CoD tests. Differences in injury burden were reported (33.28 [CG] vs. 9.55 [EG] absence days/1,000 hours exposure, rate ratio = 3.49, 95% CI 2.03-6.00, p < 0.001), but not in injury incidence. A bmRT programis suitable for improving jumping height but not linear and CoD speed performance. Additionally, bmRT may reduce injury burden, and therefore, the severity of musculotendinous injuries in U16 male soccer players.

Modeling Dynamical Positional Physical Data on Field Zones Occupied by Playing Positions in Elite-Level Futsal: A Comparison Between Running Velocities, Accelerations, and Decelerations.

ABSTRACT: Serrano, C, Felipe, JL, García-Unanue, J, Vicente Gimenez, J, Jiménez-Linares, L, Ibáñez, E, Hernando, E, Gallardo, L, and Sánchez-Sánchez, J. Modeling dynamical positional physical data on field zones occupied by playing positions in elite-level futsal: a comparison between running velocities, acceleration, and deceleration. J Strength Cond Res 37(1): 200-206, 2023-The aim of this study was to analyze the influence of playing positions on the physical demands and the specific court zones occupied during official futsal games. The total number of observations were 188, corresponding to 8 matches from the first division of the Spanish Futsal League during the 2019-2020 season. All dynamic motion representations were recorded using an 18 Hz device with ultra-wideband technology and local positioning system installed on the futsal pitch for each position. Python Data Analysis Library, Matplotlib, and Python programming language were applied as computational tools to generate visual analysis of figures to represent every physical demand analyzed. An analysis of variance test showed differences between playing positions, specifically, for winger position (p < 0.05). Based on eta-square coefficients, all variables showed large effects, except acceleration distance zone 1 (1-2 m·s-2). Accordingly, the visual representation of positional dynamic motion data showed differences in the physical demands and the court zone occupied by the different playing positions. This innovative visual analysis allows fitness coaches to associate the physical demands with court zones occupied by different playing positions, and it aids in the design of training drills associated with futsal competition requirements.

Professional Male Beach Handball Players Performance Profile.

Beach handball is a sport that has seen an increase in the number of players in the last decade. The aim of the study was to evaluate the basic measures of body composition, maturation, performance outcomes and the adherence to the Mediterranean diet of professional beach handball players, as a function of category (junior vs. senior) and playing positions. Thirty-six professional beach handball players participated in the study: 18 seniors (age: 25.0 ± 5.19) and 18 juniors (age: 16.7 ± 0.46); Each player's body composition and different sports performance variables were analysed using the CMJ test, the Abalakov test, the Yo-Yo Test IR1 and the handgrip test. The Mediterranean diet Adherence was analysed using the KIDMED questionnaire. Significant differences are observed for all performance variables, with the values of senior players being higher in all cases (p < 0.005). Moreover, the adherence to the Mediterranean diet is moderate. Positive correlations were observed between the CMJ and weight (p = 0.012) and the CMJ and the BMI (p = 0.003). The same was observed for the Abalakov test, with p = 0.004 for weight and p = 0.001 for the BMI. Regarding the dynamometry, it positively correlates with the height (p = 0.002), the sitting height (p = 0.008), wingspan (p < 0.001) and weight (p = 0.011). The opposite occurred with the Yo-Yo Test and the KIDMED variables. Conclusions: One aspect to improve, as a key performance factor, would be the adherence to the Mediterranean diet for both categories. Players with a better adherence, achieved better results in the performance tests.

Evaluation of Neuromuscular Fatigue in a Repeat Sprint Ability, Countermovement Jump and Hamstring Test in Elite Female Soccer Players.

The straight-line run is the most frequent action in soccer goal scoring situations, and it deserves considerable attention. The objective of this study was to evaluate the neuromuscular fatigue produced by an independent repeat sprint ability (RSA) test, a countermovement jump (CMJ) and a hamstring test (HT) in elite female soccer players. Twenty-four elite female soccer players participated in the study. The evaluation protocol included hamstring and CMJ tests before an RSA test (6 × 40 m 30 s rest), and hamstring and CMJ post-tests. Significant differences were found between pre-post HT measurements in the maximum angulation of the right leg (p = 0.012 Effect Size (ES) = 0.27), and the maximum velocity was higher in the left leg after RSA (p = 0.023 ES = 0.34). CMJ height after RSA was significantly lower than before the RSA test (p < 0.001 ES = 0.40). The sprint total time (SprintTT) and percentage difference (%Dif) increased throughout the RSA (p < 0.001, and ES = 0.648 and ES = 0.515, respectively). In elite female soccer players, it seems that the fatigue induced by an RSA test can be assessed through the loss of CMJ height and the different performance variables extracted from the RSA itself (e.g., SprintTT, Ideal Sprint). These findings could contribute to better performance management and injury prevention for elite female soccer players.

Physical demands in Spanish male and female elite football referees during the competition: a prospective observational study.

OBJECTIVE: The aim of this study was to analyze the physical demands of elite male and female field referees in match play and compare the physical demands between male and female football referees in the competition. METHODS: Match data were collected from 36 elite football referees (19 males and 17 females) during a total of 409 football matches. Electronic performance and tracking systems based on global positioning systems (GPS) were used in this research. RESULTS: Male referees experienced significantly greater physical demands (p < 0.05) in men league than female referees in women league for total distance, explosive distance, high-intensity breaking distance, total of sprints, sprinting distance, high-speed running distance, high-speed running actions, maximal speed, total of accelerations and decelerations, maximal acceleration and deceleration, acceleration/deceleration. CONCLUSIONS: Therefore, strength and conditioning coaches should consider these gender differences in match demands to maximize the fitness-fatigue response of the referees since this may lead to a better performance during the decision-making process in the competition.

Effect of playing position and microcycle days on the acceleration speed profile of elite football players.

The aim of this study was to analyse the differences in the A-S profile of elite football players induced by playing position and the microcycle day. Players belonged to a second division club in the Spanish La Liga competition. They were classified into five playing positions: central defenders (CD), full backs (FB), midfielders (MF), wide midfielders (WMF) and forwards (FW). Microcycle days were categorised according to the days until matchday (MD, MD-1, MD-2, MD-3, MD-4 and MD-5). Data was collected along six microcycles, including one match per microcycle. The variables analysed were: maximal theoretical acceleration (A0), maximal theoretical speed (S0), maximal acceleration (ACCmax), maximal speed (Smax) and A-S slope (ASslope). Significant differences were found within positions and microcycle day for all variables (p < 0.05). Match day (MD) showed greater values than the training sessions in A0, ACCmax and Smax (p < 0.05). The highest values for variables associated with acceleration capabilities were found in CD on MD, whereas speed variables were higher in WMF. MD-2 showed the lowest values in all variables except for ASslope. Maximal acceleration and sprint abilities are therefore affected by playing position. Wide positions showed the highest speed capacity, and CD presented a likely acceleration profile. Higher values for all variables concerning the microcycle day, were achieved on MD, and were not reproduced during training with the consequent injury risk and performance decrease it takes.

Association of the ACTN3 rs1815739 Polymorphism with Physical Performance and Injury Incidence in Professional Women Football Players.

The p.R577X polymorphism (rs1815739) in the ACTN3 gene causes individuals with the XX genotype to be deficient in functional α-actinin-3. Previous investigations have found that XX athletes are more prone to suffer non-contact muscle injuries, in comparison with RR and RX athletes who produce a functional α-actinin-3 in their fast-twitch fibers. This investigation aimed to determine the influence of the ACTN3 R577X polymorphism on physical performance and injury incidence of players competing in the women's Spanish first division of football (soccer). Using a cross-sectional experiment, football-specific performance and epidemiology of non-contact football-related injuries were recorded in a group of 191 professional football players. ACTN3 R577X genotype was obtained for each player using genomic DNA samples obtained through buccal swabs. A battery of physical tests, including a countermovement jump, a 20 m sprint test, the sit-and-reach test and ankle dorsiflexion, were performed during the preseason. Injury incidence and characteristics of non-contact injuries were obtained according to the International Olympic Committee (IOC) statement for one season. From the study sample, 28.3% of players had the RR genotype, 52.9% had the RX genotype, and 18.8% had the XX genotype. Differences among genotypes were identified with one-way analysis of variance (numerical variables) or chi-square tests (categorical variables). Jump height (p = 0.087), sprint time (p = 0.210), sit-and-reach distance (p = 0.361), and dorsiflexion in the right (p = 0.550) and left ankle (p = 0.992) were similar in RR, RX, and XX football players. A total of 356 non-contact injuries were recorded in 144 football players while the remaining 47 did not sustain any non-contact injuries during the season. Injury incidence was 10.4 ± 8.6, 8.2 ± 5.7, and 8.9 ± 5.3 injuries per/1000 h of football exposure, without differences among genotypes (p = 0.222). Injury rates during training (from 3.6 ± 3.7 to 4.8 ± 2.1 injuries per/1000 h of training exposure, p = 0.100) and match (from 47.8 ± 9.5 to 54.1 ± 6.3 injuries per/1000 h of match exposure, p = 0.209) were also similar in RR, RX, and XX football players. The ACTN3 genotype did not affect the mode of onset, the time needed to return to play, the type of injury, or the distribution of body locations of the injuries. In summary, women football players with different genotypes of the p.R577X ACTN3 polymorphism had similar values of football-specific performance and injury incidence. From a practical perspective, the ACTN3 genotyping may not be useful to predict performance or injury incidence in professional women football players.