Effect of the role, playing position and the body characteristics on physical performance in female soccer players.

The aims of this study were to know the physical demands according to the playing position and team role, and to assess the effect of the body characteristics on the physical performance of semi-professional female soccer players. Forty-five female semi-professional soccer players during 9 home-matches of the 2021-2022 season were analyzed and GPS devices (GPEXE ®) were used. ANCOVA tests were performed with playing time as covariate. The results showed greater physical demands in forwards and wide-midfielders and offensive role players. Total distance, metabolic power, accelerations, deaccelerations, and distance covered to medium and high speed obtained a strong effect size in these analyses according to the playing position. Furthermore, relationships between body weight and physical performance were found (p < 0.05). In conclusion, the main finding of this study showed that semi-professional female soccer players compete differently, caused by differentiated functions, evidenced in the playing positions and role in the team. Offensive role, forwards and wide-midfielder female players performed the highest physical demands in the competition. This study has shown relevant information for coaches, S&C coaches, and training staff of the semi-professional female soccer teams in order to propose new keys and ways of planning training sessions.

Repeated-sprint sets test: a new method for evaluating and forecasting fitness in elite young male soccer players.

The objective of the current study was to explore the correlation between repeated sprint sets (RSS) ability and several physical attributes, including maximum sprint speed, maximal aerobic speed, maximal anaerobic speed, aerobic capacity, and explosive strength. Moreover, the aim was to assess the suitability of RSS as a comprehensive evaluation tool for physical qualities and to determine which physical field tests most accurately predict RSS in elite young male soccer players. A total of thirty-two young elite male soccer players (mean age 14.6 ± 0.3 years; predicted years from peak height velocity (PHV): - 0.4 ± 0.3; years in training: 3.7 ± 0.5) voluntarily participated in the study. The players participated in eight consecutive specific physical tests, with a minimum 72-h recovery between each session to minimize the impact of fatigue during the second trial. The participants completed the tests in the following order: RSS test, Vam-Eval test, a constant velocity test performed until exhaustion at 100% of vVO2max (tlim100), 20-m Multi-Stage Shuttle Run test (VMSRT), Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1), Maximal Anaerobic Shuttle Running Test (VMASRT), Maximal Sprinting Speed Test (20-m flying sprint), Countermovement Jump (CMJ), and Standing Long Jump test (SLJ). The results of the study showed that there were very large negative correlations between tlim100 and SST (sum of sprint times), and large negative correlations between Yo-Yo IR1, Vam-Eval, and SST during RSS in young elite male soccer players (p < 0.05). Additionally, VMASRT and SLJ demonstrated a moderate negative correlation with SST (p < 0.05). In contrast, significant positive correlations were found between 20-m flying sprint and the SST (p < 0.05). According to the stepwise multiple linear regression analysis, the primary predictors of SST, ranked by importance, were tlim100 and Yo-Yo IR1. These two predictors collectively accounted for 72% of the variance in players' SST (p < 0.0001). Due to the importance of aerobic capacity and short repeated accelerations/sprint sets for overall competitive performance in soccer, in conclusion, our results suggest that elite young male soccer players should perform both high intensity interval training and aeorobic capactity exercises as part of soccer training if the primary outcome is to improve repeated sprint ability performance.

Effects of 8 weeks pre-season training on physical fitness, heart rate variability and cognition in women soccer players.

The aim of this study was to explore the variations (pre-post) of (i) Anthropometric measures: weight, body mass index, lean and muscle mass, (ii) Physical fitness: countermovement jump (CMJ) and VO2max, (iii) heart rate variability (HRV) (recumbent and sitting): mean RR, RMSSD, NN50 and NN50 %, (iv) Psychomotor Vigilance Task, and v) SART: ACC Go, ACC NoGo and reaction times in semi-professional women soccer players from the second division of the Spanish League. The analysis indicated that lean mass improved after the observation period (p = .05, d = -0.38), while no other significant changes in anthropometric measures were observed. Additionally, CMJ and aerobic power were also improved (p<.01, d>0.50). The RMSSD [recumbent (d = -0.73) and sitting (d = -0.52)] and NN50 [recumbent (d = -0.69) and sitting (d = -0.70)] increased after the period of observation (p < .05). Reaction time also significantly improved after the period of observation [PVT (d = 0.42) and SART (d = -0.89)]. Correlations performed between measures revealed that smaller body mass and body mass index were largely associated with greater NN50 (r < 0.83, p = .001). Additionally, greater CMJ and aerobic fitness were associated with greater HRV [recumbent (r = -51, p = .001) and sitting (r = -0.60, p = .01). The main findings of this study were that there was no relationship between cognitive performance and physical fitness, but HRV was related to body composition and physical fitness during the pre-season in women soccer players.

Effects of Self-Myofascial Release on Athletes' Physical Performance: A Systematic Review.

Therapists and strength and conditioning specialists use self-myofascial release (SMR) as an intervention tool through foam rollers or massage rollers for soft tissue massage, with the purpose of improving mobility in the muscular fascia. Moreover, the use of SMR by professional and amateur athletes during warm-ups, cool downs, and workouts can have significant effects on their physical performance attributes, such as range of motion (ROM) and strength. The purpose of this study was to analyse the literature pertaining to these types of interventions and their effects found in different physical performance attributes for athletes. A systematic search was carried out using the following databases: PUBMED, ISI Web of Science, ScienceDirect, and Cochrane, including articles up to September 2023. A total of 25 articles with 517 athletes were studied in depth. SMR seems to have acute positive effects on flexibility and range of motion, without affecting muscle performance during maximal strength and power actions, but favouring recovery perception and decreasing delayed-onset muscle soreness. Some positive effects on agility and very short-range high-speed actions were identified, as well. In conclusion, although there is little evidence of its method of application due to the heterogeneity in that regard, according to our findings, SMR could be used as an intervention to improve athletes' perceptual recovery parameters, in addition to flexibility and range of motion, without negatively affecting muscle performance.

The Influence of a Warm-Up on Vigilance in University Students.

The present study aimed to analyze the effects of conducting a warm-up (WC) or not (WWC) on students of the Science Degree in Physical Activity and Sport before starting a practical class. Thirty-two students of the Science Degree in Physical Activity and Sport (age: 22.38 ± 1.81 years; height: 176.09 ± 8.52 cm; weight: 22.38 ± 1.81 kg; body fat: 25.17 ± 3.20%) participated in a counterbalanced cross-sectional study in which three conditions were tested: (a) basal lineal, (b) WC, and (c) WWC. Participants recorded longer times (worse performance) in the Illinois dribbling test (basal lineal condition [20.17 ± 1.35], WWC [20.13 ± 1.37], and WC [19.32 ± 1.35]) and the Psychomotor Vigilance Task test (basal lineal condition [397.88 ± 75.98 ms]; WWC [412.19 ± 91.39 ms], and WC [368.53 ± 68.65 ms]). The warm-up prior to physical activity classes had positive effects on vigilance linked to executive functioning, and physical performance. In this sense, more research on different types of warm-up may be in order to contrast them with each other, as well as to carry out attention measurements according to the content to be imparted after the warm-ups. The present study represents a big opportunity for all physical education teachers due to warm-up is a crucial aspect that occurs in all practical sessions, also linked to the attention processes and motivational factors of the students.

Does body mass index distinguish motor proficiency, social and emotional maturity among adolescent girls?

BACKGROUND: The objective of this study was to investigate whether different body mass index (BMI) groups could serve as a distinguishing factor for assessing motor proficiency and social and emotional maturity in adolescent girls. METHODS: 140 girls ranging from 12 to 14.5 years old were selected from the schools of Tabriz city, Iran. After their height and weight were measured to calculate body mass index, they completed the following questionnaires: Bruininks-Oseretsky Test of motor proficiency, Second Edition,Vineland Social Maturity Scale, and Emotional Maturity scale. RESULTS: normal-weight girls had a meaningful advantage against overweight and underweight participants in the gross motor factor of motor proficiency (p = 0.004), but there wasn't a meaningful difference in the fine motor p = 0.196) and coordination factors (p = 0.417). Also, social maturity showed an advantage of normal and underweight adolescent girls in the self-help dressing factor (p = 0.018), while the locomotion skills (p = 0.010) factor revealed a better performance of normal weight and overweight groups over underweight adolescents. No significant differences were observed in the emotional maturity subscales (p = 0.63) between the groups. CONCLUSIONS: The present study demonstrates that BMI has a direct influence on adolescents' gross motor proficiency and social maturity.

Cause-Effect: The Relationship between Role and Experience with Psychological and Physical Responses in the Competition Context in Soccer Referees.

This study analyzed the effects of psychological responses (impulsivity, self-esteem, self-confidence, and anxiety) in baseline and pre-competitive contexts of national soccer referees (SRs), their control of the game (yellow and red cards), and physical performance (PP) according to the role (assistant or main referee), and experience in the category. Twenty-seven national SRs from Spain participated in this study. Baseline and pre-competitive psychological data were collected through the Competitive State Anxiety Inventory-2 (CSAI-2 test), Urgency, Premeditation (lack of), Perseverance (lack of), Sensation Seeking, Positive Urgency, Impulsive Behavior Scale (UPPS-P test), and Rosenberg tests. Furthermore, WIMU PRO™ inertial devices were used to monitor PP. The results indicated that a lack of perseverance and self-esteem were higher in the main SRs and somatic anxiety in assistant SRs. Experience of SRs was related to anxiety, self-confidence, self-esteem, impulsivity dimensions, and PP metrics (p < 0.05). Finally, red cards were related to positive and negative urgency (r = 0.38 and r = 0.35, p < 0.05, respectively). In conclusion, the main SRs and SRs with more experience had better psychological characteristics and PP in a competitive context. However, yellow and red cards were not associated with these factors, although red cards were related with urgency. Based on these data, specific training programs could be incorporated to enhance emotional control in SRs with less experience to achieve greater performance and professional development.

Differences and relationship in functional movement screen (FMS™) scores and physical fitness in males and female semi-professional soccer players.

Background: Soccer is the world's most popular sport for both men and women. Tests of athletic and functional performance are commonly used to assess physical ability and set performance goals. The Functional Movement Screen (FMS™) is a widely used seven-test battery developed by practitioners to provide interpretable measure of movement quality. The main objective of the present study was twofold, to analyze the relationship between FMS™ results from male and female soccer players and to compare their physical performance in different tests. Methods: A total of twenty-eight semi-professional soccer players: fourteen male (age: 21.29 ± 1.64 years; weight: 70.66 ± 5.29 kg; height: 171.86 ± 5.35 cm; BMI: 20.90 ± 2.22 kg/m2) and fourteen females (age: 20.64 ± 1.98 years; weight: 63.44 ± 5.83 kg; height: 166.21 ± 12.18 cm; BMI: 23.02 ± 2.50 kg/m2) were recruited for this study. A paired sample t-test was used for determining differences as a repeated measures analysis. All the participants conducted the following tests: The Functional Movement Test (FMS™), 10-m linear sprint, 5-0-5 COD Test and Yo-Yo Intermittent Recovery Test-Level 1 (YYIRT Level 1). Results: A t-test with data from 505 COD (change of direction) test showed significant differences between groups, p = 0.001, d = 1.11, revealing faster times in male soccer players (2.50 ± 0.19) in respect with female soccer players (2.70 ± 0.17). Crucially, a t-test with data from FMS did not reveal significant differences between groups. Multiple regression for V02max revealed significant effects (r = 0.55, r2 = 0.30, adjusted r2 = 0.24, F = 5.21, p = 0.04 and standard error = 2.20). On the other hand, multiple regression for 10-m sprint showed significant effects (r = 0.58, r2 = 0.33, adjusted r2 = 0.28, F = 5.98, p = 0.03). The impact of these factors on the correlation between FMS™ scores and physical performance measures can vary among individuals. Discussion/Conclusion: This study demonstrates the necessity of utilizing and applying multiple field-based tests to evaluate the movement and capabilities of physical performance in sports. Crucially, consider individual variations and factors such as training background, fitness level, and sport-specific demands when interpreting the relationship between the FMS™ and physical performance in both sexes.

Influence of physical fitness on decision-making of soccer referees throughout the match.

The purpose of this study was to analyze the relationships between physical fitness and physical performance in competition and the decision-making (successes and errors). A sample of 22 male national-level soccer referees (weight: 72.7 kg; height: 178.0 cm; age: 23.4 years) participated in this study. Physical fitness was assessed through 6 series of 40 m (velocity) and Yo-yo (aerobic) test in annual exam by Soccer Committee, physical performance was performed through the total distance covered in competition (Experiment 1), and decision-making was registered through a simulated Video Assistant Referee system (VAR) with the consensus of 2 national referees evaluating only warnings (yellow cards), expulsions (red cards), established penalties and obvious goal actions (called and no called) (Experiments 2 and 3). Results showed that physical fitness test was related with total distance (rho = 0.63, p < .01) and success rate percentage (rho = 0.74, p < .05) registered during competition. The success rate percentage, in the first half, was observed 44% successes, and in the second half, 59% successes. The number of events called was related with the physical fitness test score (R2 = 0.71, p = .035; R2 = 0.64, p = .056, respectively). As conclusion, the main finding of this study has provided insight into decision-making behavior in real competitive matches and the physical fitness was the predictor of the successful decision-making being able to determine the permanency, promotion or decrease of category.

Effects of combined plyometric, strength and running technique training program on change-of-direction and countermovement jump: A two-armed parallel study design on young soccer players.

CONTEXT AND OBJECTIVE: Players must be capable to have a good change-of-direction (COD) skill aiming to be the fastest as possible to react immediately to the opponent or even to help players to be more agile since COD is a physical determinant of agility. Thus, the aim of this study was to test the effects of a six-week combined training intervention in the COD and countermovement jump (CMJ) of young soccer players, while comparing with a control group only performing the regular field-based training sessions. METHODS: A sample of 80 non-professional players (40 experimental group and 40 control group) between the ages of ten and twelve was taken [(Age: 10.70 ± 1.02)]. The tests that were carried out from the beginning to the end of the intervention were: CMJ test, 505COD Test and Illinois Test. Paired sample t-test was used for determining differences as a repeated measures analysis (pre- post). An ANCOVA test was performed using the pretest as a covariate and the times pre and post as factors. RESULTS AND CONCLUSIONS: Repeated measures ANCOVA revealed significant influence of baseline level on the 5-0-5 COD (p = 0.001; ηp2=0.170), the Illinois (p = 0.018; ηp2=0.070) and the CMJ (p = 0.047; ηp2=0.050). Significant interactions group*time (p < 0.001; ηp2=0.137), 5-0-5 COD (p < 0.001; ηp2=0.274), and CMJ (p < 0.001; ηp2=0.392) were found, while no significant interactions were found in Illinois (p = 0.293; ηp2=0.014). The current research revealed that a combined training intervention consisting of strength training, plyometrics, and running techniques can be significantly beneficial for improving COD performance and CMJ.

The Effect of Environmental Disasters on Endocrine Status, Hematology Parameters, Body Composition, and Physical Performance in Young Soccer Players: A Case Study of the Aral Sea Region.

The Aral Sea region (Uzbekistan) is infamous because of the ecological disaster characterized by the disappearance of the Aral Sea due to excessive uncontrolled water intake for agriculture needs. A new desert occurrence, soil and climate aridization led to pesticide and toxic metals environment pollution. The impact of environmental conditions in some areas of Uzbekistan on the health of soccer players is not as noticeable as, for example, the effectiveness of training, so it is not widely discussed in scientific papers. The aim of the present study was to study the features of endocrine status, hematology parameters (e.g., red blood cells (RBC) and hemoglobin (Hb)), and their influence on body composition and physical fitness performance in local young soccer players of the Aral Sea region as the territory of ecological disaster. The study involved 60 male soccer players aged from 18 to 22 years. Participants were divided into two groups: the experimental group (EG), which consisted of 30 soccer players living on the territory of the Aral ecological disaster region, and the control group (CG), which included 30 soccer players, natives of the ecologically favorable region of Uzbekistan. All volunteers had anthropometric measurements, concentrations of insulin-like growth factor-1 (IGF-1), total testosterone (TT), estradiol (E2), cortisol (C), RBC, and Hb count. Moreover, Yo-Yo Intermittent Recovery Test Level 1 (YYIRT1) and professional skills tests such as dribbling shuttle test (DSt) and goal accuracy test (GAt) were assessed. When comparing the CG group to the EG group, it was observed that the EG group exhibited statistically significantly reduced levels of TT and E2 (p < 0.05). No significant statistical difference was observed between the two groups in terms of IGF-1 and C (p > 0.05). Regarding hematological parameters, Hb, Ht, and mean corpuscular volume (MCV) were found to be significantly lower in the EG compared with the CG (p < 0.05). Moreover, the distance covered in the YYIR1 test was found to be significantly lower in soccer players within the EG compared with the CG (p < 0.05). Additionally, it was determined that there was no significant difference between the groups in terms of DSt and GAt values (p > 0.05). Lastly, significant differences were observed between the EG and CG in terms of anthropometric characteristics (diameters, skinfold, and somatotype profile) (p < 0.05). The present study showed that the changes in evaluated characteristics might result from the complex influence of endocrine-disrupting chemicals, the content of which is high in the environment of the Aral Sea region. The results obtained may help monitor the health of athletes living in an environmentally unfriendly environment.

Relationship between cognitive functioning and physical fitness in regard to age and sex.

The aim of this study was to analyze the relationships among physical cognitive ability, academic performance, and physical fitness regarding age and sex in a group of 187 students (53.48% male, 46.52% female) from one town of Norwest of Jaén, Andalusia (Spain), aged between 9 and 15 years old (M = 11.97, SD = 1.99). The D2 attention test was used in order to analyze selective attention and concentration. Physical fitness, reflected on maximal oxygen uptake (VO2max), was evaluated using the 6 min Walking Test (6MWT). The analysis taken indicated a significant relationship between physical fitness level, attention, and concentration, as in the general sample looking at sex (finding differences between boys and girls in some DA score in almost all age categories [p < 0.05]) and at age category (finding some differences between the younger age category groups and the older age category groups in some DA scores (p < 0.05), not finding any significant interaction between sex and age category (p > 0.05). In sum, the present study revealed that students with better aerobic fitness can present better-processed elements and smaller omission errors. Moreover, girls and older students seem to present better cognitive functioning scores than boys and younger. Our findings suggest that more research is necessary to elucidate the cognitive function between ages, sexes, and physical fitness and anthropometry levels of students.

Effects of re-warm-up protocols on the physical performance of soccer players: A systematic review with meta-analysis.

This systematic review aimed to (1) identify and summarize studies that have examined the effects of re-warm-up (RWU) protocols on the physical performance of soccer players (vertical jump height and sprint time) and (2) establish a meta-comparison between performing a re-warm-up and not performing one regarding the outcomes of the aforementioned outcomes. A systematic review of EBSCO, PubMed, SciELO, SPORTDiscus, and Web of Science databases was performed on 12 January, 2021, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. From the 892 studies initially identified, four studies were reviewed, and three of these were included in the present meta-analysis. Compared to a control condition, there was a moderate effect of RWU on vertical jump height (ES = 0.66; p = 0.001; I2 = 0.0%). However, compared to a control condition, there was a trivial effect of RWU on linear sprint time (ES = 0.19; p = 0.440; I2 = 38.4%). The nature of RWU enhances the performance of players with an emphasis on actions requiring vertical jumps. Therefore, the results provide essential information that soccer coaching staff can use to improve the performance of their teams. The limited number of studies available for the meta-analysis may have magnified the impact of heterogeneity on linear sprint time findings. More high-quality studies, with homogeneous study designs, may help to clarify the potential benefits of RWU for linear sprint time.

Effects of Different Rapid Weight Loss Strategies and Percentages on Performance-Related Parameters in Combat Sports: An Updated Systematic Review.

Most combat sports (CS) are structured in weight categories, and it is very common to carry out body weight adjustment strategies in order to compete in lower weight categories. For this reason, different rapid weight loss (RWL) strategies are usually performed to pass the pre-competition weigh-in test, and then a replenishment of fluids and carbohydrate-rich foods is conducted in an attempt to recover the weight and avoid a performance loss. In this context, no clear references have been found on whether these types of strategies have negative effects, impairing the athlete's combat and/or physical performance. For this reason, the aim of this study was to review the scientific literature on the effect of rapid weight reduction strategies on the performance of CS athletes. A literature search was performed through four different databases (PubMed, SPORTDiscus, Web of Science and ScienceDirect). Four inclusion criteria were established as follows: (1) the subjects had to be competitors in the CS and carry out RWL strategies; (2) at least two measurement points, that is, normal conditions and dehydration condition; (3) measurements in a real competition or simulating the same conditions; (4) original research articles written in English or Spanish and available in full text. Finally, a total of 16 articles were finally included in this research. All subjects (n = 184) were athletes from combat disciplines, with a minimum of 3-4 years of practice, as well as with certain experience in RWL. Six of the studies reported that an RWL strategy of around 5% of body weight loss did not affect performance parameters. However, the other ten studies with RWL between 3 and 6% or even higher reported negative effects or impairments on different parameters related to performance and/or athlete's psychophysiology, such as perceived fatigue, mood states, strength and power production, as well as changes in hormonal, blood and urine parameters, body composition, or the kinematics of the technical gesture. Although there is still no clear answer to the issue approached in this research, in general terms, it seems that in order to guarantee an acceptable athletic performance of the competitor, the weight loss should not exceed 3% to ≤5% of body weight together with ≥24 h for adequate (or at least partial) recovery and rehydration processes. In addition, it is highly recommended to lose weight progressively over several weeks, especially focusing on competitions lasting several days, as well as multiple rounds or qualifying stages.

Differences between U23 and older semi-professional soccer players in perfectionism and passion: exploring determinant relationship between variables.

Aim: Abundant studies have pointed out that perfectionism and passion are interrelated and that they both can influence performance in a variety of contexts, including sports, however, research on how these variables interact and might affect performance in team sports, such as soccer, is still scarce. The aim of this study is to analyze differences in perfectionism and passion between under-23 years-old (U23) and older semi-professional soccer players, as well as to study the possible relationship between these two psychological variables. Methods: Participants (N = 130 healthy semi-professional Spanish soccer players) were divided into two equivalent groups according to the participants age, U23 (N = 65; 21.58 ± 1.91 years) and older than 24 years (N = 65; 30.03 ± 3.72 years) and completed self-reports on perfectionism and passion. Results: Independent samples t-test determined significant differences between the U23 Group and the >24 Group in perfectionism global score and concern over mistakes (maladaptive perfectionism), and in time, value, and passion. Multiple regression analyses revealed that obsessive passion predicted maladaptive subdimensions of perfectionism, while harmonious passion predicted adaptive perfectionism. Discussion: U23 soccer players show higher levels of maladaptive perfectionism, time, value, and passion in relation with soccer than older players, probably because at this stage pressure to become professionals and to develop their technical, tactical, and physical skills is higher than in later stages. Conclusion: Identifying differences between different age groups can help professionals in tailoring their interventions and strategies to address the specific needs of athletes at different stages of development more effectively, and to optimize mental focus, reduce stress, to promote a healthy mindset for optimal performance in soccer players, furthermore, the study of moderating effects of factors such as team dynamics or coaching styles on these constructs is advised.

The Effect of Caffeine Supplementation on Female Volleyball Players' Performance and Wellness during a Regular Training Week.

BACKGROUND: caffeine is an ergogenic aid that still needs to be investigated in women's sports performance. METHODS: Eight semi-professional women's volleyball players (height = 1.63 ± 0.08 m; weight = 66.67 ± 4.74 kg) voluntarily participated in this study. A randomized crossover design was implemented where players underwent caffeine and placebo conditions. In the caffeine condition, participants consumed 5 mg/kg of caffeine based on their body weight before acute training. The evaluations were performed over two weeks of training. In both conditions, the countermovement jump, repeated jumps for 15 s, and handgrip tests were performed. The change of direction was assessed using the 505 test. Well-being was also assessed with a wellness questionnaire. A repeated measures ANOVA and correlation analysis were performed. RESULTS: The repeated measures ANOVA revealed a main effect of supplementation (F (1.7) = 8.41, p = 0.02, η2 = 0.54) across the training week on physical performance. Additionally, there was a positive effect on perceived fatigue (F (1.7) = 7.29, p = 0.03, η2 = 0.51). CONCLUSIONS: Caffeine improved performance and fatigue parameters over one week of training. Further research is needed on women, focusing on physical performance and wellbeing, especially during intense periods.

Association between VO2max, anthropometrical measures and change of direction test in young soccer players / Asociación entre V02max, medidas antropométricas y test de cambio de dirección en futbolistas jóvenes

Objective: The use of the aerobic system is especially relevant due to the duration of the soccer game. In fact, the correct development of the aerobicsystem benefits the soccer player giving greater energy efficiency because the continuous change of energy system due to the intermittent nature of thegame causes a high consumption of glycogen. The purpose of the present study was to evaluate oxygen consumption by means of the Yo-Yo intermittenttest and anthropometrical measures, and different COD (change of direction) tests in young soccer players and to observe their possible relationship. Methods: A total of forty-seven young male soccer players (age= 15.7 ± 1.2 years; height = 188.8 ± 5.8 cm, and body mass= of 75.7 ± 8.3 kg; 7.6 ± 2.0 yearsof experience) from the region of Baleares, Spain, performed the Yo-yo test and subsequently, COD was evaluated by tests in the following order (i) V-cuttest; (ii) 505-COD test; and (iii) Illinois test. Results: A correlation analysis between VO2max and BMI revealed a moderate negative correlation, r=-0.35, p=0.01, and between VO2max and 505-COD,showed a large negative correlation, r=-0.55, p=0.001. Conclusions: The finding of the present study reveals that there is no relationship between VO2max and agility. Therefore, there is no single method toimprove VO2max and agility since both are independent variables. The different agents involved should take this into account if they want to improveVO2max and plan some aerobic resistance exercises; and to improve agility they must plan agility exercises separately.(AU)

Objetivo: El uso del sistema aeróbico es especialmente relevante debido a la duración del partido de fútbol. De hecho, el correcto desarrollo del sistemaaeróbico beneficia al futbolista otorgándole una mayor eficiencia energética ya que el continuo cambio de sistema energético debido a la naturalezaintermitente del juego provoca un alto consumo de glucógeno. El propósito del presente estudio fue evaluar el consumo de oxígeno mediante la pruebaYo-Yo intermitente y medidas antropométricas, y diferentes pruebas COD (cambio de dirección) en jóvenes futbolistas y observar su posible relación. Métodos: Un total de cuarenta y siete jóvenes futbolistas masculinos (edad= 15.7 ± 1.2 años; altura = 188.8 ± 5.8 cm, y masa corporal= de 75.7 ± 8.3 kg;7.6 ± 2.0 años de experiencia) de la región de Baleares, España, realizó la prueba Yo-yo y posteriormente, se evaluó la DQO mediante pruebas en elsiguiente orden (i) prueba de corte en V; (ii) prueba 505-COD; y (iii) prueba de Illinois. Resultados: Un análisis de correlación entre VO2max e IMC reveló una correlación negativa moderada, r=-0.35, p=0.01, y entre VO2max y 505-CODmostró una correlación negativa grande, r=-0.55, p=0.001. Conclusiones: El hallazgo del presente estudio revela que no existe una relación entre el VO2max y la agilidad. Por lo tanto, no existe un método único paramejorar el VO2max y la agilidad ya que ambas son variables independientes. Los diferentes agentes implicados deberían tener esto en cuenta si quierenmejorar el VO2max y planificar algunos ejercicios de resistencia aeróbica; y para mejorar la agilidad deben planificar ejercicios de agilidad por separado.(AU)

Effects of a small-sided games training program in youth male soccer players: variations of the locomotor profile while interacting with baseline level and with the accumulated load.

PURPOSE: This study aimed to (1) analyze the impact of a small-sided game training program in the locomotor profile of youth male soccer players (while interacting with the baseline level - higher and lower level); and (2) test the relationships between variation in locomotor profile and the accumulated demands in 3v3, 5v5 and match over the period of observation. METHODS: The cohort lasted 3-weeks. Twenty under-17 male amateur soccer players (16.8 ± 0.41 years; experience: 6.35 ± 0.67 years) were assessed twice for their final velocity at 30-15 intermittent fitness test (VIFT), peak speed at 30-m sprint test (PSS) and anaerobic speed reserve (ASR). The PSS was estimated using a Global Positioning System, while the VIFT was estimated using the maximum level attained by the players during the test. Based on the baseline levels, the scores were standardized using the Z-score. The total score of athleticism (TSA) was calculated per player to organize the players into two groups: lower TSA and higher TSA. Over the three weeks of observation, the small-sided games of 3v3 and 5v5 and match demands were monitored using polar team pro. The heart rate responses (mean and peak), distance covered (overall and split by speed thresholds), and peak speed in these games were obtained and summed over the weeks. The repeated measures ANCOVA tested the variations (time) of the locomotor profile of players while considering the baseline as covariable and the group as a factor. The Pearson-product correlation test analyzed the relationships between variations in locomotor profile (Δ, post-baseline) and the accumulated demands in 3v3, 5v5, and match. RESULTS: Between-groups analysis (lower TSA vs. higher TSA) revealed no significant differences on VIFT (p = 0.915), PSS (p = 0.269), ASR (p = 0.258) and TSA score (p = 0.138). Within-group (baseline vs. post-observation) analysis revealed significant difference on VIFT (p < 0.001), PSS (p = 0.008), while no significant differences were found on ASR (p = 0.949) and TSA score (p = 0.619). Significant correlations were found between ΔPSS and match total distance (r = 0.444; p = 0.050), match Z2 (r = 0.481; p = 0.032) and match Z3 (r = 0.454; p = 0.044). Significant correlations were found between ΔTSA and match total distance (r = 0.457; p = 0.043), match Z1 (r = 0.451; p = 0.046), match Z2 (r = 0.500; p = 0.025) and match Z3 (r = 0.468; p = 0.037). CONCLUSION: Significant improvements were observed after the period of observation. However, the fitness baseline level and the accumulated training load in the small-sided games seem to have no significant impact on the observed improvements.

Dehydration, Wellness, and Training Demands of Professional Soccer Players during Preseason.

Purpose: Our study is aimed at analyzing the relationships between water loss and a professional soccer team's internal and external training load throughout the first three months of a season, covering all the preseason and the first two months of the competitive season. Methods: This study followed an observational analytic design. Twenty-seven athletes (age: 25.5 ± 4.1 years, height: 180.7 ± 8.2 cm, and body mass: 78.4 ± 8.7 kg) were included in the study, conducted over the first three months of the season. Players were weighed at the beginning and end of all training sessions to estimate fluid losses. They were asked to complete a wellness questionnaire and indicate the color of the first urine of the day upon their arrival at the practice session. Additionally, all sessions were monitored for locomotor demands. Results: We found a positive correlation between urine color and sprint distance (r = 0.46, p = 0.01) and a positive correlation between dehydration and rating of perceived exertion (r = 0.44, p = 0.015), whereas a negative correlation between dehydration and number of acceleration (r = -0.39, p = 0.034). Conclusions: Dehydration increased perceived physical exertion. Regularly monitoring training load and changes in body mass, as well as raising awareness about hydration, can contribute to cognitive and physical performance.

Relationships between Internal Training Intensity and Well-Being Changes in Youth Football Players.

The aim of this study was two-fold: (i) to analyze the variations of training intensity and well-being measures of youth football player over a 38 week period; and (ii) to test the relationships between training intensity and well-being variations throughout a youth football season. This study followed a longitudinal design, lasting 38 weeks. Twenty-five players (age: 15.0 ± 0.4 years) participated in this study. Participants were monitored daily to quantify the training intensity (TI) using the session-rate of perceived exertion (s-RPE) and its related indices: training monotony (TM), weekly training intensity (wTI), mean training intensity (mTI), and 5-day average (5d-AVG). A four-item questionnaire was collected daily to quantify the well-being status of each player. Fatigue, stress, delayed onset muscle soreness (DOMS), sleep quality, and the Hooper Index (HI) measures were analyzed. Kruskal-Wallis H test revealed significant differences for TM, mTI, wTI and 5d-AVG (H = 359.53, p = 0.001, η2 = 0.35; H = 414.97, p = 0.001, η2 = 0.41, H = 258.42, p = 0.001, η2 = 0.24 and H = 282.18, p = 0.001, η2 = 0.26). A positive large correlation was found between TM and sleep quality (r = 0.65, p = 0.05) and a negative large correlation between mTI and sleep quality (r = -0.69, p = 0.04). In conclusion, both TI and well-being measures present significant between-week differences at different periods of the season. Also, the variations of sleep quality seem to depend on TM and mTI variations across a youth football season.