Influence of contextual factors on match running performance of starters and non-starters in elite youth male soccer players.

This study investigated the effects of match location, quality of opposition (classified into: strong [1st to 4th position]; intermediate [5th to 15th position]; weak [16th to 20th position]), and match outcome on the match running performance of starters and non-starters from a top elite Brazilian soccer team. Absolute measures were calculated using total distance, high-speed (19.8-25.2 km·h-1), sprinting (≥ 25.2 km·h-1), total distance high-acceleration (> 2m·s2), and deceleration (< -2m·s2) were recorded by GPS units from a sample of young soccer players (N = 25) in a total of 17 matches. Relative measures were calculated by dividing absolute measures by the total duration of the matches. Non-starters covered greater total distance (p = 0.02), sprinting (p = 0.02), high-acceleration and deceleration (p = 0.04), sprinting distance relative per minute played (p = 0.005), and high-acceleration and deceleration relative per minute played (p < 0.001) when the team plays at home, strong opponents, and wins the matches. Starters covered greater total distance in high-speed running (p = 0.04), high-acceleration and deceleration (p = 0.03), and high-speed running relative per minute played (p = 0.04) when the team plays strong opponents and wins the matches. These findings highlight the impact of contextual factors during matches on the locomotor performance of young soccer players.

What We Do Not Know About Stretching in Healthy Athletes: A Scoping Review with Evidence Gap Map from 300 Trials.

BACKGROUND: Stretching has garnered significant attention in sports sciences, resulting in numerous studies. However, there is no comprehensive overview on investigation of stretching in healthy athletes. OBJECTIVES: To perform a systematic scoping review with an evidence gap map of stretching studies in healthy athletes, identify current gaps in the literature, and provide stakeholders with priorities for future research. METHODS: Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 and PRISMA-ScR guidelines were followed. We included studies comprising healthy athletes exposed to acute and/or chronic stretching interventions. Six databases were searched (CINAHL, EMBASE, PubMed, Scopus, SPORTDiscus, and Web of Science) until 1 January 2023. The relevant data were narratively synthesized; quantitative data summaries were provided for key data items. An evidence gap map was developed to offer an overview of the existing research and relevant gaps. RESULTS: Of ~ 220,000 screened records, we included 300 trials involving 7080 athletes [mostly males (~ 65% versus ~ 20% female, and ~ 15% unreported) under 36 years of age; tiers 2 and 3 of the Participant Classification Framework] across 43 sports. Sports requiring extreme range of motion (e.g., gymnastics) were underrepresented. Most trials assessed the acute effects of stretching, with chronic effects being scrutinized in less than 20% of trials. Chronic interventions averaged 7.4 ± 5.1 weeks and never exceeded 6 months. Most trials (~ 85%) implemented stretching within the warm-up, with other application timings (e.g., post-exercise) being under-researched. Most trials examined static active stretching (62.3%), followed by dynamic stretching (38.3%) and proprioceptive neuromuscular facilitation (PNF) stretching (12.0%), with scarce research on alternative methods (e.g., ballistic stretching). Comparators were mostly limited to passive controls, with ~ 25% of trials including active controls (e.g., strength training). The lower limbs were primarily targeted by interventions (~ 75%). Reporting of dose was heterogeneous in style (e.g., 10 repetitions versus 10 s for dynamic stretching) and completeness of information (i.e., with disparities in the comprehensiveness of the provided information). Most trials (~ 90%) reported performance-related outcomes (mainly strength/power and range of motion); sport-specific outcomes were collected in less than 15% of trials. Biomechanical, physiological, and neural/psychological outcomes were assessed sparsely and heterogeneously; only five trials investigated injury-related outcomes. CONCLUSIONS: There is room for improvement, with many areas of research on stretching being underexplored and others currently too heterogeneous for reliable comparisons between studies. There is limited representation of elite-level athletes (~ 5% tier 4 and no tier 5) and underpowered sample sizes (≤ 20 participants). Research was biased toward adult male athletes of sports not requiring extreme ranges of motion, and mostly assessed the acute effects of static active stretching and dynamic stretching during the warm-up. Dose-response relationships remain largely underexplored. Outcomes were mostly limited to general performance testing. Injury prevention and other effects of stretching remain poorly investigated. These relevant research gaps should be prioritized by funding policies. REGISTRATION: OSF project ( https://osf.io/6auyj/ ) and registration ( https://osf.io/gu8ya ).

Comparison of the external load of professional goalkeepers in different weekly training sessions.

The aim of this study was to compare the external load of professional goalkeepers (GKs) in different training sessions of the microcycle. Three professional GKs (age: 28.1 ± 6.9 years; stature: 190.1 ± 1.9 cm; body mass: 84.8 ± 1.1 kg) were monitored by GPS devices during different training sessions according to the days since/until the match day (MD) at MD+1, MD-4, MD-3, MD-2 and MD-1. Different external load measures were calculated: total distance, distance covered at > 14 km · h-1, acceleration load, player load, number of dives, dive load, number of explosive efforts of displacement, number of low intensity (< 0.3 m), medium intensity (0.3-0.4 m), high intensity (> 0.4 m) and medium-high intensity jumps (> 0.3 m). The results showed that there is a decrease in the external load as the GKs' training sessions approach the match, with the lowest value of external load observed at MD-1, and the highest external loads at MD+1 and MD-4. This analysis of the external load demands of professional soccer GKs provides new information that will be useful to inform professionals when planning and implementing training and/or recovery strategies for soccer GKs during the microcycle.

Effects of Upper-Body and Lower-Body Conditioning Activities on Postactivation Performance Enhancement During Sprinting and Jumping Tasks in Female Soccer Players.

ABSTRACT: Santos da Silva, V, Nakamura, FY, Gantois, P, Nogueira Gouveia, JN, Peña, J, Beato, M, and Abade, E. Effects of upper-body and lower-body conditioning activities on postactivation performance enhancement during sprinting and jumping tasks in female soccer players. J Strength Cond Res 38(2): 342-349, 2024-This study aimed to investigate the postactivation performance enhancement (PAPE) effects of "specific" (half-back squat) and "nonspecific" (bench press) conditioning activities on sprinting and jumping performances in female soccer players. Fourteen players (mean ± SD : age = 22.3 ± 4.0 years; body mass = 60.2 ± 7.8 kg; height = 164.1 ± 4.2 cm) competing at national level (first League) participated in this within-subject crossover study. The players performed a warm-up protocol including 3 sets of 3 repetitions of half-back-squat or bench press exercises at 90% 1RM or a warm-up protocol without lifting weights (i.e., control condition). Forty-meter shuttle sprints (20 + 20 m with change of direction [COD-180°]), countermovement jump (CMJ), and horizontal jump (HJ) performances were recorded 6 minutes after the conditioning activities protocols or the control condition. Nonsignificant large positive effects were found for the HJ after the half-back-squat (ES = 1.68; p > 0.05) and bench press (ES = 1.68; p > 0.05) protocols. Although nonsignificant, HJ changes ( Δ = 0.07 m) were greater than the smallest worthwhile change (0.02 m) and standard error of measurement (0.03 m) after both conditioning activities. Moreover, no significant changes were found for sprint and CMJ performance after neither half-back-squat nor bench press protocols ( p > 0.05). In conclusion, both specific and nonspecific conditioning activities using heavy loads (i.e., 90% 1RM) may be suitable to enhance individual HJ. Finally, both conditioning activities are potentially ineffective for increasing sprint and CMJ performance in the context of this study.

Revisiting the 'Whys' and 'Hows' of the Warm-Up: Are We Asking the Right Questions?

The warm-up is considered beneficial for increasing body temperature, stimulating the neuromuscular system and overall preparing the athletes for the demands of training sessions and competitions. Even when warm-up-derived benefits are slight and transient, they may still benefit preparedness for subsequent efforts. However, sports training and competition performance are highly affected by contextual factors (e.g., how is the opponent acting?), and it is not always clear what should be the preferred warm-up modalities, structure and load for each athlete and context. Further, we propose that the warm-up can also be used as a pedagogical and training moment. The warm-up may serve several different (albeit complementary) goals (e.g., rising body temperature, neuromuscular activation, attentional focus) and be performed under a plethora of different structures, modalities, and loads. The current commentary highlights the warm-up period as an opportunity to teach or improve certain skills or physical capacities, and not only as a preparation for the subsequent efforts. Moreover, the (justified) call for individualized warm-ups would benefit from educating athletes about exploring different warm-up tasks and loads, providing a broad foundation for future individualization of the warm-up and for more active, engaged, and well-informed participation of the athletes in deciding their own warm-up practices.

The Effects of Neuromuscular Training on Sand Versus Hard Surfaces on Physical Fitness in Young Male Tennis Players.

PURPOSE: To examine the effects of a neuromuscular training program combining plyometric exercises with acceleration, deceleration, and change-of-direction drills conducted on sand or hard surfaces on the fitness qualities of young male tennis players. METHODS: Thirty-one young male players were allocated to a training group performing 12 training sessions on sand or hard surfaces, during a 6-week period. Tests included linear sprint (10-m acceleration with 5-m split times), change of direction (modified 5-0-5 test), vertical jumps (countermovement jump and the 10/5 repeated-jump test), isometric hip abduction and adduction strength, and dynamic balance (Y-balance test). Perceived training loads and muscle soreness were assessed during the intervention. RESULTS: Both training strategies were similarly effective in improving the analyzed fitness components. Group × time interaction effects were noticed, with countermovement jump (P = .032), repeated-jump test (P = .029), and reactive strength index (P = .008) favoring hard surfaces and 5-m sprint (P = .009), dynamic balance (P < .05), adduction strength (P < .05), and abduction strength (P < .001) indices favoring sand. Furthermore, the sand group promoted greater perceived training loads and muscle soreness (P < .05) than the hard group across the intervention period. CONCLUSION: Neuromuscular training strategies characterized by a relatively low volume (∼35 min), conducted on sand or hard surfaces, promoted similar improvements in the fitness qualities of young tennis players, with selected surface-interaction effects. Training on sand can cause transiently higher training loads and persistently higher muscle soreness, suggesting the need for an adequate familiarization period.

Eccentric overload differences between loads and training variables on flywheel training.

There is considerable debate about the existence of a real eccentric overload in flywheel exercises. This study aimed to analyse the differences in concentric: eccentric mechanical output ratios between different loads and variables in the flywheel squat exercise. Twenty physically active men (22.9 ± 2.2 years, height: 1.8 ± 0.1 m, weight: 79.6 ± 8.2 kg) performed a loading test using five moments of inertia. Angular speed was measured using a rotary encoder, while the vertical force was measured using force plates. For each variable (angular speed, angular acceleration, power, vertical force, and torque), mean and peak values were calculated for concentric and eccentric phases to allow comparisons across the loads. We tested the possible differences in Load × Phase (concentric and eccentric) and Load × Variable. The level of significance was established as p < 0.05. A significant Load × Phase interaction was found in mean angular speed, peak vertical force, peak angular acceleration, peak power and peak torque. Higher eccentric overload values were observed with speed-derived variables (angular speed, angular acceleration and power). In conclusion, speed-derived peak variables and lower loads are more likely to show an eccentric overload and can be used to monitor responses to flywheel training.

Using Bar Velocity to Assess Post-match Neuromuscular Fatigue in Young Soccer Players.

This study aimed to investigate the recovery of neuromuscular performance using mechanical parameters collected during jump (vertical and horizontal) and strength-power exercises in youth soccer players after official soccer matches. Twenty-one outfield highly trained youth male soccer athletes (age: 18.23 ± 0.73 years; weight: 72.12 ± 6.99 kg; height: 1.78 ± 0.08 m) from two teams competing in the 1st division of U-19 Portuguese National Championship participated in this study. Players completed a battery of physical tests at -2h, +30 min, +24h, and +48h in relation to the match. Countermovement jump height, horizontal jump distance, and bar velocity during the half-squat, bench press, and hip-thrust exercises, at fixed loads, were recorded. Countermovement jump was impaired until 24h post-match (-1.7% from pre to 24h post, p=0.050; ES=-0.82). Half-squat bar velocity was reduced immediately following the match (-6.8 % from pre- p=0.004; ES=-0.64) but recovered at +24h (+2.9%, p=1.00; ES=0.02). Hip-thrust bar velocity was reduced for up to 48h post-match (-7.4% from pre to 48h post, p<0.001; ES=-0.80). No impairments were found in the horizontal jump and bench press at any moment. Our findings show prolonged decrements in strength of the posterior chain following a soccer match, measured in the hip-thrust exercise, while the other exercises displayed faster recovery dynamics.

Total and regional body composition are related with aerobic fitness performance in elite futsal players.

Body composition (i.e., fat and lean mass profile) has been related to aerobic performance, an essential capacity for futsal athletes. The present study aimed to verify the relationship between total and regional body composition (percentage of fat and lean mass) with aerobic performance in elite futsal players. Male professional futsal athletes (n = 44) from two Brazilian National Futsal League teams and athletes representing the National team participated in this study. Body composition was evaluated using DXA (Dual-Energy X-ray Absorptiometry) and aerobic fitness by ergospirometry. There was a negative (p < 0.05) correlation between maximum oxygen uptake and maximal velocity reached with total body (r = -0.53; r = -0.58), trunk (r = -0.52; r = -0.56) and lower-limb (r = -0.46; r = -0.55) fat mass percentage. Lower-limb lean mass percentage had a positive (p < 0.05) correlation with maximum oxygen uptake (r = 0.46) and maximal velocity (r = 0.55). In conclusion, total and regional body composition present a relationship with aerobic performance in professional futsal players.

Analysis of velocity- and power-load relationships of the free-weight back-squat and hexagonal bar deadlift exercises.

The aim of this study was to analyse the load-velocity and load-power relationships in the free-weight back-squat (BSQ) and hexagonal bar deadlift (HBD) exercises. Twenty-five (n = 25) resistance-trained men (age = 23.7 ± 2.8 years) performed a progressive load test at maximal intended velocity to determine their BSQ and HBD one-repetition maximum (1RM). Mean propulsive velocity (MPV) during the concentric phase of the lift was recorded through a linear encoder. Load-velocity and load-power relationships were analysed by fitting linear regression and the second-order polynomial, respectively, to the data. Maximum strength (1RM), MPV (30-80% 1RM), and power output (30-90% 1RM) were higher for HBD compared to BSQ exercise (p < 0.05). A very strong relationship between MPV and relative intensity was found for both BSQ (R2 = 0.963) and HBD (R2 = 0.967) exercises. The load that maximizes power output (Pmax) was 64.6 ± 2.9% (BSQ) and 59.6 ± 1.1% (HBD) 1RM. There was a range of loads at which power output was not different than Pmax (BSQ: 40-80% 1RM; HBD: 50-70% 1RM). In conclusion, the load-velocity and load-power relationships might assist strength and conditioning coaches to monitor and prescribe exercise intensity in the BSQ and HBD exercises using the velocity-based training approach.

The Effects of a Compensatory Training Program Adding an Isoinertial Device in the Shoulder Function on Young Tennis Players.

ABSTRACT: Fernandez-Fernandez, J, Moreno-Perez, V, Cools, A, Nakamura, FY, Teixeira, AS, Ellenbecker, T, Johansson, F, and Sanz-Rivas, D. The effects of a compensatory training program adding an isoinertial device in the shoulder function on young tennis players. J Strength Cond Res 37(5): 1096-1103, 2023-The aim of this study was to analyze whether a compensatory training program, including isoinertial flywheel training, could reduce shoulder imbalances in a group of asymptomatic young tennis players. After an initial evaluation, 26 young tennis players were assigned to either a supervised flywheel training group (FTG, n = 13) or a control group (CG, n = 13). Shoulder passive internal (IR) and external rotation (ER) range of motion (ROM) as well as shoulder IR and ER maximal isometric strength were measured before and after a 12-week training intervention, performed 3 times per week. After the intervention, results showed significant changes for IR ( p < 0.001, effect size [ES] = 1.83) and ER ( p < 0.001, ES = 1.77) on the dominant (D) side, and IR on the nondominant (ND) side ( p < 0.001, ES = 2.24) in the FTG compared with the CG. Regarding the ROM values, results showed that the FTG achieved significantly greater increases for the IR ROM ( p < 0.001, ES = 3.32) and total ROM (TROM) ( p = 0.004, ES = 1.39) on the D and ND sides (IR ROM: p = 0.002, ES = 1.53; TROM: p < 0.001, ES = 2.35) than the CG. Moreover, the CG displayed larger decrements in ER ROM ( p = 0.016, ES = 1.12) on the ND side after the training period than the FTG. The conducted compensatory training program was effective to increase the ER strength and IR mobility of the FTG players, which led to a reduction in the glenohumeral imbalances.

The effects of different small-sided games configurations on heart rate, rating of perceived exertion, and running demands in professional soccer players.

We examined the effects of different small-sided games (SSG) configurations on heart rate (HR), rating of perceived exertion (RPE), and running demands in soccer players. Twelve male soccer players (U18) participated in this randomized cross-over study. Players performed three SSG in different "fixed" and "dynamic" pitch sizes (3v3 in large (SSGL) and small (SSGS) fixed area; or 3v3 in dynamic dimensions [SSGD]), with 4x4 minutes interspersed by 2 minutes of rest. HR measures (maximum [HRmax], average [HRavg], and percentage of maximum [%HRmax]), RPE, and running demands were collected across the SGG sessions. The following running activities were recorded: total distance covered (TD), distance covered (DC) at 6-12 km·h-1, ≥ 12-18 km·h-1, and >18 km·h-1, peak running speed, acceleration (ACC) and deceleration (DEC) at 1-2 m·s-2 and 2-3 m·s-2, player load, and high metabolic load distance (HMLD). SSGL displayed higher HRavg, %HRmax, and RPE values than SSGS (p < 0.05). SSGL resulted in higher TD, DC at 6-12 km·h-1, ≥ 12-18 km·h-1, > 18 km·h-1, and higher peak speed than SSGS and SSGD (p < 0.05). Moreover, SSGD presented higher TD and DC at 6-12 km·h-1 and ≥ 12-18 km·h-1 than SSGS (p < 0.05). In contrast, SSGD and SSGS showed higher number of ACC and DEC at 1-2 m·s-2 than SSGL (p < 0.05). In conclusion, the pitch size and playing area of the SSG can be manipulated to promote desired physiological and physical demands in young soccer players.HighlightsWe examined how fixed (small and large) or variable (dynamic) pitch sizes affected the psychophysiological and running demands of young soccer players during small-sided games.Small-sided games with larger pitch sizes and areas per player elicited greater psychophysiological and running demands than small areas.The pitch size designed in the current study does not appear to affect the number of acceleration and deceleration (> 2 m·s-2).Varying the pitch size during the small-sided games (i.e. dynamic condition) could be an interesting constraint to be considered by soccer coaches in order to enhance task variability.

Playing videogames or using social media applications on smartphones causes mental fatigue and impairs decision-making performance in amateur boxers.

This study aimed to analyze the effect of playing videogames and using social media applications on smartphones on decision-making and countermovement jump (CMJ) performance in amateur boxers. Twenty one boxers were enrolled in the study and were randomly assigned to all three experimental conditions [smartphone (30SMA), videogame (30VID), and control (CON)]. CMJ was measured before and 30-min after each experimental condition. The athletes ran simulated combat recorded for decision-making analysis. The boxers watched coaching videos (CON), used social media applications on smartphones (30SMA), and played video games (30VID) for 30 min just before the combat simulation. Both attack and defense decision-making performance were worse in both 30SMA and 30VID conditions compared to the CON condition (p = 0.001). Regarding CMJ, despite no condition effect (p = 0.96) been obtained, a time effect (p = 0.001) was observed; So, it was found a decrease in CMJ performance after all experimental conditions (p = 0.001), with no difference between them. Using social media applications on smartphones and playing video game impairs decision-making performance in amateur boxers, with no harms for CMJ performance.

Acceleration and deceleration demands during training sessions in football: a systematic review.

PURPOSE: The aim of this review is to summarize the current scientific knowledge about acceleration and deceleration demands during football training. METHODS: A systematic search of three electronic databases (PubMed, SPORTDiscus, Web of Science) was performed to identify peer-reviewed relevant English-language articles, following PRISMA guidelines. RESULTS: All acceleration and deceleration data were analyzed and organized into four categories: i) training drills variables (i.e. manipulated drills variables such as number of players in small-sided games), ii) training exercises (i.e. different drills such small games or circuit training), iii) players' positions (i.e. demands for each playing position) and iv) training schedule (i.e. training sessions presented as microcycles, season sections or full season). Full-text articles of 42 studies were included in the final analysis. Players' level included: amateur, youth, semi-professional, professional and elite players. All playing positions were considered, including goalkeepers. Six different global position systems brands were used, with the majority measuring data at 10 Hz. Different thresholds and intensities were used in several papers. Lower acceleration and deceleration intensities occurred more often than higher intensities in all four categories. CONCLUSION: Different exercises elicit different demands and small-sided games presented higher acceleration and deceleration demands than circuit training and other running based drills. Furthermore, manipulating drills variables, as reducing or increasing number of players in small-sided games increase or decrease demands, respectively. Additionally, wide playing positions, such as fullbacks, are generally exposed to higher acceleration and deceleration demands. From a planning point of view, acceleration and deceleration demands decrease as match day approaches.

Ongoing Bidirectional Feedback between Planning and Assessment in Educational Contexts: A Narrative Review.

Quality in education is one of the 17 goals in the United Nations' sustainable agenda for 2030, presupposing careful planning and assessment of learning. Traditional planning in sports education (either in training or school settings) largely adopts pre-determined learning sequences and temporal milestones that, in theory, enhance the learning process. However, learning is a context-dependent, non-linear process with considerable intra- and interindividual variability, whereby planning and assessment should also be non-linear. In this narrative review, the main findings suggest that the specific teaching or training contents and their relative (i.e., ordering or sequencing) and absolute timing (i.e., the specific time point where certain learning or adaptations are expected) should vary depending on the learners and the context. In a process-oriented perspective, this requires flexible planning and the establishment of ongoing bidirectional links between planning and assessment. In this framework, assessment should be a flexible, evolving, and daily pedagogical tool instead of a set of formal checkpoints. We further explored how planning and assessment could be linked to provide an ongoing feedback loop that respects the individuality of each learner and its context, and therefore hope this review helps bring about a change in current planning and assessment paradigms in sports education.

Microdosing: Old Wine in a New Bottle? Current State of Affairs and Future Avenues.

PURPOSE: Microdosing of exercise aims to deliver smaller daily training doses but at a higher weekly frequency, adding up to a similar weekly volume as in nonmicrodosed training. This commentary critically discusses this concept, which appears to be a rebranding of the "old" distributed practice of motor learning. DEVELOPMENT: We propose that microdosing should relate to the minimal dose that develops or at least maintains the selected capacities or skills as this training dose matters to practitioners, especially during the in-season period. Moreover, microdosing has been applied mainly to develop strength and endurance, but abilities such as sprinting and changing direction could also be microdosed, as well as technical-tactical skills. CONCLUSIONS: The concept of microdosing should be reframed to avoid redundancy with the concept of distributed practice while providing valuable information concerning the minimum doses that still generate the intended effects and the thresholds that determine whether a dose is "micro" or not.

Factors associated to the market value of professional soccer players / Factores asociados al valor de mercado de los futbolistas profesionales / Fatores associados ao valor de mercado de jogadores profissionais de futebol

The objective of this study was analysed to the market value (MV) of professional soccer players from Top-5 European Soccer Leagues. An ANOVA analysed the effect of the independent variables on the MV of the soccer players, with p<0.01. Soccer players from the Premier League (PL) showed greater MV compared to other leagues. Foreign soccer players showed greater MV compared to national soccer players. Soccer players between 21-30 years showed greater MV compared to those <21 and >30 years. Forward and midfielders showed greater MV compared to goalkeepers and backs. Soccer players that represented their countries at international matches showed greater MV compared to those that did not. The soccer players with a youth background formation in their clubs in the Premier League and La Liga showed greater MV compared to soccer players coming from other clubs. In conclusion, extrinsic factors affect the MV of soccer players. Research results may be useful to the sport managers in the selection of professional soccer players. (AU)

El objetivo de este estudio fue analizar el valor de mercado (VM) de futbolistas profesionales de las 5 mejores ligas europeas de fútbol. Se analizó el efecto de las variables independientes sobre el VM de los futbolistas, mediante una ANOVA con un nivel de significación de p <0.01. Los futbolistas de la Premier League (PL) mostraron mayor VM en comparación con los de otras ligas. Los futbolistas extranjeros mostraron mayor VM en comparación con los futbolistas nacionales. Los futbolistas entre 21-30 años mostraron mayor VM en comparación con los <21 y > 30 años. Los delanteros y centrocampistas, mostraron mayor VM en comparación con los porteros y los laterales. Los futbolistas que representaron a sus países en partidos internacionales mostraron mayor VM en comparación con los que no lo hicieron. Los futbolistas de formación juvenil en clubes de la PL y La Liga (LL) mostraron mayor VM en comparación con los futbolistas de otros clubes. En conclusión, factores intrínsecos y extrínsecos afectan el VM de los futbolistas. Los resultados de esta investigación pueden ser útiles para los directores deportivos en el proceso de selección de futbolistas profesionales. (AU)

O objetivo deste estudo foi analisar o valor de mercado (VM) de jogadores de futebol profissional das 5 melhores ligas europeias de futebol. O efeito das variáveis independentes sobre a VM dos futebolistas foi analisado por meio de uma ANOVA com nível de significância de p <0,01. Os jogadores de futebol da Premier League (PL) apresentaram MV mais alto em comparação com os de outras ligas. Os jogadores de futebol estrangeiros apresentaram VM superior em comparação aos jogadores de futebol nacionais. Jogadores de futebol entre 21-30 anos apresentaram maior VM em comparação com aqueles com <21 e> 30 anos. Os atacantes e meio-campistas mostraram maior VM em relação aos goleiros e laterais. Os jogadores de futebol que representaram seus países em jogos internacionais apresentaram maior MV em comparação com aqueles que não o fizeram. Jogadores de futebol em formação de jovens em clubes da PL e La Liga (LL) apresentaram maior VM em comparação com jogadores de futebol de outros clubes. Em conclusão, fatores intrínsecos e extrínsecos afetam a VM dos jogadores de futebol. Os resultados desta pesquisa podem ser úteis para dirigentes esportivos no processo de seleção de jogadores profissionais de futebol. (AU)

Reducing Big Data to Principal Components for Position-Specific Futsal Training.

Since training/competition loads must be quickly assessed and interpreted to inform exercise prescription, big data should be simplified through multivariate data analysis. Our aim in the present research was to highlight which variables from big data analyses provided the most relevant information for describing the behavior of top-level futsal players in their different playing positions (i.e., goalkeeper, defenders, wingers, and forwards). We collected data from four top-level Spanish teams that participated in the final rounds of a national tournament. Through principal component analysis (PCA) we grouped 6-9 variables in 3-4 PCs that explained 62-81% of total variance, depending on playing positions. The most relevant variables explaining goalkeepers' performance were accelerations per minute, maximum acceleration (m/s2), 5-8 impacts per minute, and < 3 takeoffs per minute. Defenders' behavior was best explained by absolute distance covered from 6-12 km/h (m/min) and from 18-21 km/h (m/min), from 5-8 landings per minute, and > 8 landings per minute. Wingers' and pivots' performances were mainly explained by accelerations and decelerations, together with a high level of aerobic endurance (especially for wingers). These findings allow for individualized training and game analysis.

Three Simulated Goalball Games in the Same Day Cause Central Fatigue and Can Impair Game Technical Performance.

The purpose of this study was to investigate the effects of three simulated goalball games on neuromuscular, physiological, perceptual, and technical parameters. Ten male players underwent assessments before and immediately after each game. Heart rate was recorded at rest and during all games that were entirely filmed for further technical performance analysis. Exercise significantly decreased knee extensor muscles peak force and percentage of voluntary activation after the second and third games, indicating the presence of central fatigue. Heart rate responses remained predominantly in a range equivalent to moderate activity intensity in all games. In addition, perceptual parameters were associated with reduced frequency of throws and density of actions. These findings suggest significant implications for the management of physical training, game strategy during a competition, and fixture change from three to two games per day.

Effects of congested fixture and matches' participation on internal and external workload indices in professional soccer players.

This study aimed to verify the effects of congested fixture and matches' participation on internal and external workload indexes in professional Brazilian soccer players. Rate of perceived exertion-based training load (sRPE), distance- and accelerometry-based measures were daily monitored over 119 training sessions and 33 matches performed by 29 male outfield players. Weeks were classified as congested (n = 11, two or more matches within a 7-day period) and regular (n = 10, one match or less within a 7-day period). The players were divided based on the matches' participation: (1) players who played ≥ 60 min (G1); (2) players who played < 60 min (G2); (3) players who did not participate of the match (G3). The findings showed that independent of the levels of participation during the matches, regular weeks presented greater acute, monotony, and strain indices for internal and external workload measures than congested weeks. The G1 presented the highest values for most of the workload indices in both regular and congested weeks, except for monotony indices (internal and external load) that G2 showed greater values than G1 and G3. Coaches and practitioners should plan the training "doses" to reduce disparities of these different match's participation and congested schedule weeks.