Search

Background and purpose: Historically, sports training methodology, including soccer coaching, has been influenced by the pedagogic tend dominant in each epoch. Of late, the literature has espoused the idea that human learning is individual, nonlinear, and complex. Nonlinear Pedagogy (NLP) takes into account such nonlinearity and complex phenomena and facilitates each person's learning through a methodology of manipulating constraints. This learner-environment-centered approach conducts players and teams to a tactical behavior emerging through playing modified versions of games using a rich range of different constraints, for example the introduction of artificial rules. Despite the attractions of training based on constraints to research, few studies have empirically assessed the effects of these programs from a tactical perspective. The present study applies the NLP pedagogical principles of representativeness and constraints manipulation to provide youth sport academy coaches with empirical evidence of the training effects of modified games on team tactical behavior. Specifically, this study aimed to assess the short-term training effects of modified games introducing artificial rules on team tactical behavior during the team possession game phase in two youth soccer categories. Methods: Thirty-two Spanish male youth soccer players from the under-14 (U14: n = 16; age: 13.0 ± 0.4 years; playing experience: 6 ± 1 years; height: 1.56 ± 0.07 m; body mass: 46.7 ± 5.9 kg) and the under-16 (U16: n = 16; age: 15.9 ± 0.4 years; playing experience: 8 ± 1 years; height: 1.70 ± 0.07 m; body mass: 57.9 ± 8.3 kg) teams of the same club participated in the study. The natural groups were not modified for the study and the participants had some prior experience with modified games. Each team was divided into two groups who played each other during a short-term intervention distributed across four training sessions: control (CON: free play without restrictions) and experimental (EXP: modified games introducing artificial rules). Team tactical behavior was assessed, including the goalkeeper (Gk) and during the team possession game phase, using a local positioning system (LPS) before and after the intervention in an 8-a-side game with the official offside rule. Findings: Linear team tactical behavior change in centroid position, dyads, and total area values barely changed (d = trivial -- small [0.01-0.34]) after a short-term intervention of free play and modified games. Team tactical behavior tended toward greater regularity (sample entropy decrease) after artificial rules were introduced in comparison with free play without restrictions. Youth sport academy coaches who opt for organized and regular behavior during the team possession game phase could employ modified games introducing artificial rules to build up repeatable tactical patterns. Conversely, those who prefer being more chaotic and unpredictable in the game could take advantage of free play without restrictions.

Background and purpose: Historically, sports training methodology, including soccer coaching, has been influenced by the pedagogic tend dominant in each epoch. Of late, the literature has espoused the idea that human learning is individual, nonlinear, and complex. Nonlinear Pedagogy (NLP) takes into account such nonlinearity and complex phenomena and facilitates each person's learning through a methodology of manipulating constraints. This learner–environment-centered approach conducts players and teams to a tactical behavior emerging through playing modified versions of games using a rich range of different constraints, for example the introduction of artificial rules. Despite the attractions of training based on constraints to research, few studies have empirically assessed the effects of these programs from a tactical perspective. The present study applies the NLP pedagogical principles of representativeness and constraints manipulation to provide youth sport academy coaches with empirical evidence of the training effects of modified games on team tactical behavior. Specifically, this study aimed to assess the short-term training effects of modified games introducing artificial rules on team tactical behavior during the team possession game phase in two youth soccer categories. Methods: Thirty-two Spanish male youth soccer players from the under-14 (U14: n = 16; age: 13.0 ± 0.4 years; playing experience: 6 ± 1 years; height: 1.56 ± 0.07 m; body mass: 46.7 ± 5.9 kg) and the under-16 (U16: n = 16; age: 15.9 ± 0.4 years; playing experience: 8 ± 1 years; height: 1.70 ± 0.07 m; body mass: 57.9 ± 8.3 kg) teams of the same club participated in the study. The natural groups were not modified for the study and the participants had some prior experience with modified games. Each team was divided into two groups who played each other during a short-term intervention distributed across four training sessions: control (CON: free play without restrictions) and experimental (EXP: modified games introducing artificial rules). Team tactical behavior was assessed, including the goalkeeper (Gk) and during the team possession game phase, using a local positioning system (LPS) before and after the intervention in an 8-a-side game with the official offside rule. Findings: Linear team tactical behavior change in centroid position, dyads, and total area values barely changed (d = trivial – small [0.01–0.34]) after a short-term intervention of free play and modified games. Team tactical behavior tended toward greater regularity (sample entropy decrease) after artificial rules were introduced in comparison with free play without restrictions. Youth sport academy coaches who opt for organized and regular behavior during the team possession game phase could employ modified games introducing artificial rules to build up repeatable tactical patterns. Conversely, those who prefer being more chaotic and unpredictable in the game could take advantage of free play without restrictions. [ABSTRACT FROM AUTHOR]

The aim of this study was to describe the team accumulated physical response per minute considering only the effective playing time (EPT) attending to different contextual and strategic variables in the Spanish Football First Division (LaLiga Santander). A sample of 2,959 performances was included in the analysis, considering a 4-year period of analysis (from 2016-17 to 2019-20). The physical variables were: total distance covered with (DTminPOS) and without (DTminNOpos) possession of the ball, and distance covered at > 21 kmh-1 with possession (DT21minPOS) and without (DT21minNOpos). Two contextual variables, i.e. Place (Home/Away) and Score (Lost/ Draw/Win), and two strategic variables, i.e. level of effective playing time (LevelETP) and level of possession of the ball (LevelPOS), were analysed. The teams ran more without possession of the ball than with possession; nevertheless, the teams that had less possession of the ball had higher values in the distance covered at > 21 km h-1 with possession of the ball and vice versa. Furthermore, the strategic variables also had influence on the physical response (DT and DT21) of the teams,LevelETP and LevelPOS, although with interactive effects: longer playing time, less accumulated distance, and greater possession, greater accumulated distance in the defensive phase, both per min. The findings of this study may offer important practical implications to practitioners in order to assess physical performances of the players in matches, because it is crucial to integrate in the analysis the different contextual and strategic variables where the match has taken place to assess performances of the teams. [ABSTRACT FROM AUTHOR]

The objective of the study was to assess the impact of the sampling frequency on the outcomes of collective tactical variables during an official women's soccer match. To do this, the first half (lasting 46 min) of an official league match of a semi-professional soccer team belonging to the Women's Second Division of Spain (Reto Iberdrola) was analysed. The collective variables recorded were classified into three main groups: point-related variable (i.e., change in geometrical centre position (cGCp)), distance-related variables (i.e., width, length, height, distance from the goalkeeper to the near defender and mean distance between players), and area-related variables (i.e., surface area). Each variable was measured using eight different sampling frequencies: data every 100 (10 Hz), 200 (5 Hz), 250 (4 Hz), 400 (2.5 Hz), 500 (2 Hz), 1000 (1 Hz), 2000 (0.5 Hz), and 4000 ms (0.25 Hz). With the exception of cGCp, the outcomes of the collective tactical variables did not vary depending on the sampling frequency used (p > 0.05; Effect Size < 0.001). The results suggest that a sampling frequency of 0.5 Hz would be sufficient to measure the collective tactical variables that assess distance and area during an official soccer match. [ABSTRACT FROM AUTHOR]

Copyright of Cultura, Ciencia y Deporte is the property of Cultura, Ciencia y Deporte and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Match collective tactical behaviours can be used as a reference to design and select training strategies to improve individual and team performance in professional football. The aim of the systematic review was to cluster the collective tactical variables used to highlight and compare male soccer teams' collective behaviour during professional official matches, providing reference values for each of them. A systematic review of relevant articles was carried out using three electronic databases (PubMed, SPORTdiscus and Web of Science). From a total of 1,187 studies initially found, 13 original articles were included in the qualitative synthesis. The articles found concerned studies carried out on the Spanish, Portuguese, English and Brazilian 1st divisions and during the European UEFA Champions League. The team length and width ranged from 31 to 46 m and from 35 to 48 m, respectively. The distance from a defending team's goalkeeper to the nearest teammate ranged from 9 ± 6 to 30 ± 7 m, the goal line-recovery location from 27 to 37 m, and the opponent's goal line from 42 to 50 m. The stretch index ranged from 7 to 16 m. Mean team area was ~900 m² and the area of the pitch which included all outfield players divided by the 20 outfield players ranged from 79 ± 15 to 94 ± 16 m². All studies provided greater distance and area values during the team-possession phase in comparison to the non-possession one. The ball location on the pitch determined the collective tactical behaviour of the teams. The differences between halves in the distance and area values were contradictory. Further studies should assess the effect of the interaction between the contextual factors on the collective tactical behaviour to obtain more accurate references. This could help football coaches in the design of suitable training tasks to optimize tactical performance. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to assess the respiratory and muscular session ratings of perceived exertion (PE) after official soccer matches over an extended period of time (ie, 2 competition seasons) in relation to playing time (>20, 20-45, 45-70, and >70 min) and to determine the between-matches variability of both scores in young professional soccer players. Methods: Forty players belonging to the same reserve team of a Spanish La Liga club participated in this study. Respiratory and muscular PE were collected 10 min after every game. A total of 841 individual PE ratings were undertaken on outfield players. Results: The differences between match respiratory and muscular load differ depending on the playing time, the respiratory PE being greater for the players that competed less than 45 min (effect size = -0.45 ± 0.45 for the 20- to 45-min group) and the muscular PE greater for players that played more than 45 min (effect size = 0.23 ± 0.30, for the 45- to 70-min group). Match-to-match PE variability was considerable (CV = 14-54%) for all levels of participation, but it was lower the longer the players participated. Conclusions: Playing time influenced the relative exertion that players' respiratory and leg musculature were exposed to during a game, suggesting that differential PE scores might provide a more accurate evaluation of match-imposed internal load. However, the small-magnitude differences between respiratory and muscular session ratings of PE observed in the current study might question the practical relevance of assessing both scores. [ABSTRACT FROM AUTHOR]

This study analyses the differential perceived match load accumulated by professional soccer players depending on their: (a) participation in several consecutive official matches within the same week (Pre_Cup, Cup, and Post_Cup), and (b) total match participation time (i.e. 90 min, 70–90 min and < 70 min). Participants were 21 Spanish Second Division professional soccer players (M age = 27.1, SD = 3.3 years; M body height = 182.1, SD = 3.9 cm; M body mass = 75.8, SD = 5.14 kg). There were no significant differences (p > 0.05) in dRPE-ML among Pre_Cup, Cup and Post_Cup matches or in dRPE-ML between teams that took part in two or three official matches within the same week or three official matches in 2–4 consecutive weeks. The results suggest that participating in several matches in the same week does not increase accumulated perceived exertion for professional soccer players. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to compare the effects of 2 strength and conditioning programs involving either purely vertically oriented or combining vertically and horizontally oriented exercises on soccer-relevant performance variables (ie, acceleration, jumping ability, peak power, and endurance). Methods: Twenty-two professional male soccer players were randomly assigned to 2 training groups: vertical strength (VS, n = 11) and vertical and horizontal strength (VHS, n = 11). Players trained 2 times per week during all the preseason (5 wk) and 3 weeks of the competitive season. The effect of the training protocols was assessed using double-and single-leg vertical countermovement jumps (CMJ), half-squat peak power (PP), sprint performance over 5 and 15 m, and blood lactate concentration at selected running speeds. Results: Both groups obtained significant improvements in PP (P < .05; ES = 0.87 and 0.80 for VS and VHS, respectively) and small practical improvements in 5-m- (P < .05; ES = 0.27 and 0.25 for VS and VHS, respectively) and 15-m-sprint time (P < .05; ES = 0.19 and 0.24 for VS and VHS, respectively). The CMJ performance showed a small improvement (P < .05, ES = 0.34) only in the VHS group. Submaximal aerobic-fitness changes were similar in both groups (P < .05; ES = 1.89 and 0 .71 for VS and VHS, respectively). Conclusion: This study provided a small amount of practical evidence for the consideration of preseason training protocols that combine exercises for vertical- and horizontal-axis strength development in professional male soccer players. Further studies using more aggressive training protocols involving horizontally oriented conditioning exercises are warranted. [ABSTRACT FROM AUTHOR]

Copyright of RICYDE. Revista Internacional de Ciencias del Deporte is the property of Revista Internacional de Ciencias del Deporte and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Although many studies on collective tactical behaviour have been published in the last decade, no study has revised and summarized the findings provided for futsal. The main aim of this systematic review was to identify and discuss the geometrical centre (GC), distance and area tactical variables used to assess team behaviour in futsal. In addition, it summarizes the findings on the tactical response during futsal competition and training. A systematic review of the relevant articles provided on futsal was carried out using seven electronic databases (SPORTDiscus, ProQuest, Cochrane Plus, Scopus, Google Scholar, PubMed and Web of Science) until September 25, 2019. From a total of 1,209 studies initially found, 12 were included in the qualitative synthesis. There were some trends in the analysis of positional data in futsal with the most relevant situations analysed being 1 vs 1 and 5 vs 4+Goalkeeper. The distances and angles between two points were the most assessed tactical variables. Five types of distance variables were used to assess collective tactical behaviour in futsal: GC-GC, GC-player, player-player, player-ball and player-space. Pressure (GC-GC) was greater in shots on goal than in tackles during professional futsal matches. Area variables were reduced to occupied space, exploration space and dominant area. Occupied space was measured only during competition while the dominant area was measured only during training sessions. The surface area and dominant regions were greater when players were attacking in comparison to when they were defending. In addition, two non-linear techniques (i.e. relative phase and entropy) were applied to analyse synchronisation and complexity and regularity or predictability. Defenders were highly synchronous, while attackers tried to break this coordination to achieve possibilities for action. Task constraints are suitable to induce different regularity patterns. This review is an opportunity to develop studies aimed at bridging the gap in collective tactical behaviour in futsal. [ABSTRACT FROM AUTHOR]

The aim of the study was to compare the agreement of the data on the kinematic demands and collective tactical variables during a professional soccer match between GPS and UWB sensors. The data were extracted from a professional soccer match played in "the regular season" during 2019-2020. The analysis indicated a high-degree of agreement between UWB and GPS sensors to measure the total distance covered (ICC>0.94). In addition, Bland-Altman plots showed a low average difference for the total distance covered between the devices (mean difference = -0.011 to -0.017 m). Although the collective tactical variable (i.e. surface area) showed a high-degree of agreement between both devices (i.e. ICC>0.84), a significant main effect was found for the average difference between the UWB sensor and GPS sensor (mean difference = -9.25 to 57.41 m2). In addition, Bland-Altman plots showed a slight systematic bias for lower surface area measured by the GPS sensor in comparison to the UWB sensor. Researchers and technical staff should consider that the data provided by the GPS and UWB can be interchangeable in the analysed kinematic variables. However, the data provided by the devices cannot be compared in the analysed collective variables due to the differences found. [ABSTRACT FROM AUTHOR]

The use of valid, accurate and reliable systems is decisive for ensuring the data collection and correct interpretation of the values. Several studies have reviewed these aspects on the measurement of movement patterns by high-definition cameras (VID) and Global Positioning Systems (GPS) but not by Local Positioning Systems (LPS). Thus, the aim of the review was to summarize the evidence about the validity and reliability of LPS technology to measure movement patterns at human level in outdoor and indoor stadium-scale. The authors systematically searched three electronic databases (PubMed, Web of Science and SPORTDiscus) to extract studies published before 21 October 2019. A Boolean search phrase was created to include sport (population; 8 keywords), search terms relevant to intervention technology (intervention technology; 6 keywords) and measure outcomes of the technology (outcomes; 7 keywords). From the 62 articles found, 16 were included in the qualitative synthesis. This systematic review revealed that the tested LPS systems proved to be valid and accurate in determining the position and estimating distances and speeds, although they were not valid or their accuracy decreased when measuring instantaneous speed, peak accelerations or decelerations or monitoring particular conditions (e.g., changes of direction, turns). Considering the variability levels, the included studies showed that LPS provide a reliable way to measure distance variables and athletes' average speed. [ABSTRACT FROM AUTHOR]

Copyright of RICYDE. Revista Internacional de Ciencias del Deporte is the property of Revista Internacional de Ciencias del Deporte and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of the study was to assess the use of different positioning systems and sampling frequencies to measure spatial-positioning variables in team sports. Articles were selected when the sampling frequency was detailed. 2,194 articles were identified and 59 works were selected for the systematic review. The sampling frequency used to measure tactical behaviour differed considerably among studies. For Global Navigation Satellite System, the sampling frequency ranged from 5- to 15 Hz for raw data, the most commonly used sampling frequency being 5 Hz. For Optic-based tracking systems, the sampling frequency ranged from 10- to 30 Hz. For Local Position System, the sampling frequency ranged from 45- to 100 Hz, the most commonly used sampling frequency being 42 Hz and 57.7 Hz. There is no common criterion in the sampling frequency used to measure each tactical variable. Further studies should investigate the impact of the sampling frequency on the measurement of the tactical variables. [ABSTRACT FROM AUTHOR]

This study aims at assessing physical fitness performance and its relationship with the differential ratings of perceived exertion of training load (dRPE TL) and match load (dRPE ML) in a Spanish professional soccer team at the beginning of several in-season periods: 1–4 weeks, 5–8 weeks and 1–8 weeks. Performance and mechanical variables over the acceleration phase, as well as cardiovascular performance variables were evaluated in 20 male professional soccer players of a team competing in the Spanish Second Division League. Moreover, dRPE TL and dRPE ML were quantified. The dRPE TL showed negative and large associations between both maximal aerobic speed (MAS) and maximal oxygen consumption (VO2max) (from r = −0.53; ± 0.06 to r = −0.53; ± 0.05 95% CL, p= 0.035 to 0.036) and RPEres TL values throughout the 5–8 and 1–8 week periods. Furthermore, dRPE ML positive and large associations were found between players initial MAS or VO2max (from r = 0.50; ± 0.17 to r = 0.56; ± 0.11 95% CL, p= 0.026 to 0.049) and RPEmus ML in 1–4 and 1–8 week periods. The current study suggests that a better cardiovascular capacity could be connected with a lower RPEres TL and higher RPEmus ML. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study was to examine the changes in aerobic fitness in young elite Spanish soccer players after the pre-competitive period over 12 seasons depending on the initial performance level and the tactical position. Methods: One hundred and thirty players belonging to the same reserve team of a Spanish La Liga Club participated in this study. Aerobic fitness capacity (the velocity associated with a blood lactate concentration [La]b of 3 mmol l-1 [V3]) was assessed in each season at the start of the preseason (i.e. July), Test 1 (T1), and the start of the competitive period (i.e. September), Test 2 (T2), from 1998 to 2013 season. Results: Taking all seasons together a most likely small improvement (effect size (ES) = 0.52; ±0.09) was found in V3 after preseason, but this varied from trivial to moderate among the seasons. A most likely large improvement was found for the players with lower V3 values in T1 (ES = 1.68; ±0.38) while a likely small enhancement was assigned to the group with higher V3 values (ES = 0.53; ±0.42). Conclusions: Technical staff should be cautious about affirming an improvement in aerobic fitness after preseason. [ABSTRACT FROM AUTHOR]

Los Arcos, A and Martins, J. Physical fitness performance of young professional soccer players does not change during several training seasons in a Spanish elite reserve team: club study, 1996–2013. J Strength Cond Res 32(9): 2577–2583, 2018—The purpose of this study was to assess the changes in physical fitness performance in young professional soccer players during several training seasons in a Spanish elite reserve team. Physical test values (i.e., vertical jump test, straight line sprint test, and discontinuous and progressive submaximal running test) of 97 young professional soccer players who belonged for at least 2 consecutive seasons to the reserve team of a Spanish professional team from 1996 to 2013 were analyzed. A distinction was made between the soccer players who were promoted to the Spanish first/second divisions (n = 38) and those who were not (n = 59) (until the end of the 2016/2017 season). Players were also classified according to their playing positions. Independently of the competitive level reached and the playing position, the variability of the fitness performance was limited (coefficient of variation <6%) and the players did not improve their fitness values (effect size ≤ small) from the first to the last season in which they were enrolled in the team (after 2–4 seasons). During the last stage of training in an elite soccer academy, young professional soccer players achieve a very similar physical fitness performance when their soccer competence is evaluated, and other soccer performance factors are those which make them stand out for selection. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the association of perceived respiratory and muscular exertions and associated training load (TL) for monitoring changes in several aerobic fitness and neuromuscular performance parameters during 32 weeks of soccer training in young professional players. Twenty male soccer players (age=20.6±1.8 years, body height=1.80±.06 m, body mass=73.6±6.7 kg) belonging to the same reserve team of a Spanish La Liga Club participated in this study. Countermovement jump (CMJ), CMJ with arm swing, linear sprint running (over 5 m and 15 m) and an aerobic fitness running test were performed at the start of the pre-season (Test 1) and 32 weeks later (Test 2). During these eight months, after each training session and match, players rated their perceived exertion (sRPE) separately for respiratory (sRPEres) and leg musculature (sRPEmus) effort. Training load was calculated by multiplying the sRPE value by the duration of each training session or match. Accumulated training and match volume (i.e., time) and associated respiratory and muscular training loads were negatively correlated with the changes in aerobic fitness performance after 32 weeks of training (r=-.53/-.62). In addition, accumulated perceived respiratory load was negatively correlated with the changes in 15 m sprint performance (r=-.51/-.53). A high practice volume (time) and associated respiratory and leg muscular TL can impair the long-term improvement of aerobic fitness and sprint performance in professional soccer players. [ABSTRACT FROM AUTHOR]

The aim of the present study was to analyse the training load in wheelchair basketball small-sided games and determine the relationship between heart rate (HR)-based training load and perceived exertion (RPE)-based training load methods among small-sided games bouts. HR-based measurements of training load included Edwards’ training load and Stagno’s training impulses (TRIMPMOD) while RPE-based training load measurements included cardiopulmonary (session RPEres) and muscular (session RPEmus) values. Data were collected from 12 wheelchair basketball players during five consecutive weeks. The total load for the small-sided games sessions was 67.5 ± 6.7 and 55.3 ± 12.5 AU in HR-based training load (Edwards’ training load and TRIMPMOD), while the RPE-based training loads were 99.3 ± 26.9 (session RPEres) and 100.8 ± 31.2 AU (session RPEmus). Bout-to-bout analysis identified greater session RPEmus in the third [P < 0.05; effect size (ES) = 0.66, moderate] and fourth bouts (P < 0.05; ES = 0.64, moderate) than in the first bout, but other measures did not differ. Mean correlations indicated a trivial and small relationship among HR-based and RPE-based training loads. It is suggested that HR-based and RPE-based training loads provide different information, but these two methods could be complementary because one method could help us to understand the limitations of the other. [ABSTRACT FROM PUBLISHER]

The aims of this study are (a) to describe the evolution of neuromuscular performance over an 18 year period within a Spanish elite reserve team; (b) to check if there were any relation between the playing position and sprint and jump performances and (c) to look into the alleged impact of this factor on the top playing level attained by the soccer players. We considered the physical tests (5 m and 15 m sprint times and countermovement jump (CMJ) height) made by 235 players enrolled in the reserve team of the Club from 1994 to 2012 and the highest competitive-level they achieved: Spanish first (n = 39) and second divisions (n = 36) and semi-professional (n = 160). Furthermore, the players were classified according to their playing positions. The main findings were a very-likely/most-likely lower neuromuscular performance (ES = 0.48–0.68, small to moderate) in the last six-season term (2006–2012) than in the first term (1994–2000); possibly/very-likely lower performances in sprinting and CMJ (ES = 0.22–0.55, small) by central defenders (CDs) and midfielders than by other playing positions; very-likely better performances in sprinting and jumping by first and second divisions central defenders than by semi-professional central defenders (ES = 0.90–1.02, moderate). Sprint and jump performances are not a relevant physical parameter to promote to the top level of soccer in Spain except for one in six of the playing positions: CDs. [ABSTRACT FROM PUBLISHER]

The aim of this study was to examine the dose response effect of strength and conditioning programmes, involving horizontally oriented plyometric exercises, on relevant soccer performance variables. Sixteen soccer players were randomly allocated to two 6-week plyometric training groups (G1 and G2) differing by imposed (twice a week) training volume. Post-training G1 (4.13%; d = 0.43) and G2 (2.45%; d = 0.53) moderately improved their horizontal countermovement jump performance. Significant between-group differences (p < 0.01) in the vertical countermovement jump for force production time (T2) were detected post-training. No significant and practical (p > 0.05, d = trivial or small) post-training improvements in sprint, change of direction ability (CODA) and horizontal arm swing countermovement jump were reported in either group. Horizontal plyometric training was effective in promoting improvement in injury prevention variables. Doubling the volume of a horizontal plyometric training protocol was shown to have no additional effect over functional aspects of soccer players' performance. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the relationship between perceived respiratory and muscular training load (TL) and changes in physical fitness in elite and non-elite junior soccer players. Twenty-eight elite (n = 14, 17.6 ± 0.6 years, 70.3 ± 4.4 kg, 179.7 ± 5.6 cm) and non-elite (n = 14, 17.5 ± 0.5 years, 71.1 ± 6.5 kg, 178.1 ± 5.6 cm) soccer players belonging to a Spanish first and third division football academies and competing in junior Spanish first division (2012–2013) participated in the study. Countermovement jump (CMJ), CMJ arm swing, 5 and 15 m sprints and the Université de Montreal endurance test were performed in January and 9 weeks later in March. In order to quantify TLs, after each training session and match, players reported their session rating of perceived exertion (sRPE) separately for respiratory (sRPEres) and leg musculature (sRPEmus). Elite players accumulated greater weekly training volume (361 ± 14 vs. 280 ± 48 min; effect sizes (ES) = 5.23 ± 1.74; most likely), and perceived respiratory (1460 ± 184 vs. 1223 ± 260 AU; ES = 1.12 ± 0.79; very likely) and muscular (1548 ± 216 vs. 1318 ± 308 AU; ES = 0.99 ± 0.84; likely) TL than did non-elite players. Training volume, sRPEres-TL and sRPEmus-TL were positively and largely correlated (r = 0.67–0.71) with the changes in aerobic fitness. The present results suggest that a low training volume and TL can impair improvement in aerobic fitness in junior soccer players during the in-season period. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare the effects of Small-Sided Games (SSG) vs. Interval Training (IT) in soccer training on aerobic fitness and physical enjoyment in youth elite soccer players during the last 8 weeks of the season. Seventeen U-16 male soccer players (age = 15.5 ± 0.6 years, and 8.5 years of experience) of a Spanish First Division club academy were randomized to 2 different groups for 6 weeks: SSG group (n = 9) and IT group (n = 8). In addition to the usual technical and tactical sessions and competitive games, the SSG group performed 11 sessions with different SSGs, whereas the IT group performed the same number of sessions of IT. Players were tested before and after the 6-week training intervention with a continuous maximal multistage running field test and the counter movement jump test (CMJ). At the end of the study, players answered the physical activity enjoyment scale (PACES). During the study, heart rate (HR) and session perceived effort (sRPE) were assessed. SSGs were as effective as IT in maintaining the aerobic fitness in elite young soccer players during the last weeks of the season. Players in the SSG group declared a greater physical enjoyment than IT (P = 0.006; ES = 1.86 ± 1.07). Coaches could use SSG training during the last weeks of the season as an option without fear of losing aerobic fitness while promoting high physical enjoyment. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the usefulness of the rating of perceived exertion training load for monitoring changes in several aerobic fitness and neuromuscular performance variables during 9 weeks of soccer training in young professional players. Nineteen male soccer players (20.2 ± 1.9 years) belonging to the same reserve team of a Spanish La Liga Club participated in this study. Countermovement jump (CMJ), CMJ arm swing, single leg CMJ, a sprint running test (i.e., 5 m and 15 m times) and an aerobic fitness running test were performed at the start of the pre-season (Test 1) and 9 weeks later (Test 2). During 9 weeks, after each training session and match, players reported their rating of perceived exertion (RPE) separately for respiratory (RPEres) and leg musculature (RPEmus) effort. The training load (TL) was calculated by multiplying the RPE value by the duration in minutes of each training session or match. Accumulated RPEmus, and associated TL, as well as accumulated training volume were negatively correlated with the changes in most physical fitness attributes after 9 weeks of training (r = -0.51 to -0.64). Present results suggest that a high perception of leg muscular effort associated with training sessions and matches, as well as an excessive accumulation of training volume (time), can impair the improvement in several physical fitness variables believed to be relevant for on-field soccer performance. Therefore, the independent assessment of leg muscular effort to quantify TL can be an interesting additional monitoring measure in soccer training. [ABSTRACT FROM AUTHOR]

The article discusses research which investigated fluctuations in rating of local-muscular (sRPEmus) and central-respiratory (sRPEres) perceived exertion measured after the completion of each training and competitive session in professional soccer players. Researchers evaluated 21 players. They found that at the end of matches average sRPEmus was higher than sRPEres and concluded that RPEmus should be considered the main fatigue rating during a soccer match.

Background: Bilateral strength imbalance in the lower extremities has been studied in several sports as well as cycling and running. However, there has been little investigation of the differences in muscle strength and leg asymmetries in vertical jump between elite runners and cyclists. Research question: The primary purpose of this investigation was to determine the differences in vertical jump capacity between elite athletes (runners and cyclists). A secondary purpose was to describe single leg vertical jump capacity and leg asymmetries in elite athletes. Type of study: The evaluation sessions consisted of a different vertical jump tests. Methods: 27 elite male endurance athletes (endurance runners and road cyclists) performed a countermovement jump (CMJ), single leg CMJ, arm swing CMJ and a 10 s repeat jump (RJ) test. Results: The runners had a significantly greater (p < 0.01) jump performance in the double leg CMJ (19%), arm swing CMJ (27%) and RJ (16%) compared with cyclists. Similarly, single leg vertical jump performance was significantly better in runners compared with cyclists both with reference to the right leg CMJ (13.4%, p < 0.05), left leg CMJ (15.5%, p < 0.05), dominant leg CMJ (12.6%, p < 0.05) and non-dominant leg CMJ (16.4%, p < 0.01). Significant differences between dominant leg CMJ and non-dominant leg CMJ performance in jump height (leg asymmetry 5.5%) and power production (leg asymmetry 6.5%) were found in the runners' group. In the cyclists' group, significant differences were also found between dominant leg CMJ and non-dominant leg CMJ jump height (leg asymmetry 9.7%) and power production (leg asymmetry 14.6%). Conclusions: The present study demonstrated a markedly higher single and double leg vertical jump capacity in elite endurance runners compared with professional road cyclists. [ABSTRACT FROM AUTHOR]

The aim of this study was to profile physical characteristics of soccer players measured by acceleration, vertical jump (VJ), horizontal jump (HJ) and change of direction ability (CODA) tests, and to quantify the relationships between these characteristics. Additionally, leg asymmetries between the dominant and nondominant legs during unilateral VJ and HJ were assessed. Thirty-nine male soccer players (22.9±2.8 years, 179.9±6.01 cm, 77.0±8.3 kg), competing in the third division of the Spanish Soccer League, participated in this study. Soccer experience of these players amounted to 15.19±3.15 years. Significant moderate correlations (p<.05) were found between all HJ tests and the modified agility (MAT) or the 505 test, and between all VJ tests and the Y20 or the 505 test. The significant differences between the dominant and non-dominant legs were found for the horizontal drop jump test (p=.001, d=.66) and horizontal three jump test (p=.017, d=.33). No significant differences between the dominant and non-dominant legs were found for VJ tests. The correlation between jumping and CODA varied depending on the characteristics of test types. The significant leg asymmetry in horizontal jumps with bounds found in the present study suggests that soccer players have greater leg asymmetries in the horizontal jump than in the vertical jump. [ABSTRACT FROM AUTHOR]

The article discusses research which was conducted to examine the intrasubject intraclass coefficient correlation (CCI) and the intersubject variability (CVI) of soccer ball drills (BD) involving or not involving opposition in male youth soccer. Researchers evaluated 14 male soccer players. They found that soccer ball drills did not induce homogeneous physiological responses in young soccer players and that their use may be questionable in training.

The article discusses the effect of eccentric hamstring strengthening exercises on the thigh muscles of male professional soccer players as observed with functional magnetic resonance imaging (fMRI). Imaging of the subjects before and after performing leg curl and lunge exercises indicated load-related changes in the semitendinosus, adductor magnus, and biceps femoris long head muscles. It is suggested that the results can applied to the prevention and treatment of acute hamstring injuries.

Ultra-wide band (UWB) based local positioning systems (LPS) are based on devices and a portable antenna set. The optimal installation height of the antennae is crucial to ensure data accuracy. Collective variables are metrics that consider at least two pairs of coordinates, which may lead to lower precision than an individual one. Therefore, the aim of this study was to compare the influence of antenna height with collective metrics using a UWB (i.e., IMU; WIMU PRO™, RealTrack Systems, Almeria, Spain) based LPS. Data acquisition was carried out in a basketball court measuring 28 × 15 m. Five devices were used; one of which was carried by a healthy and well-trained athlete (age: 38 years, mass: 76.34 kg, height 1.70 m), while each of the remaining four was positioned on a tripod in one of the four corners of the court. Four kinds of variables were extracted: (1) static distances, (2) dynamic distances, (3) static areas and (4) dynamic areas in all antenna installation modes of 0.15, 1.30 and 2.00 m. The results showed that the antenna of 1.30 m provided better accuracy for all measures (% difference range from −0.94 to 1.17%) followed by the antenna of 2.00 m (% difference range from −2.50 to 2.15%), with the antenna of 0.15 m providing the worst accuracy level (% difference range from −1.05 to 3.28%). Overall, the measurements of distance metrics showed greater accuracy than area metrics (distance % difference range from −0.85 to 2.81% and area % difference range from −2.50 to 3.28). In conclusion, the height of the antennae in basketball courts should be similar to the height at which the devices are attached to a player's upper back. However, as the precision is sensitive to the magnitude of the measure, further studies should assess the effects of the relative height of antennae in team sports with greater playing spaces. [ABSTRACT FROM AUTHOR]

Electronic performance and tracking systems (EPTS) and microelectromechanical systems (MEMS) allow the measurement of training load (TL) and collective behavior in team sports so that match performance can be optimized. Despite the frequent use of radio-frequency (RF) technology (i.e., global positioning navigation systems (GNSS/global positioning systems (GPS)) and, local position systems (LPS)) and MEMS in sports research, there is no protocol that must be followed, nor are there any set guidelines for evaluating the quality of the data collection process in studies. Thus, this study aims to suggest a survey based on previously used protocols to evaluate the quality of data recorded by RF technology and MEMS in team sports. A quality check sheet was proposed considering 13 general criteria items. Four additional items for GNSS/GPS, eight additional items for LPS, and five items for MEMS were suggested. This information for evaluating the quality of the data collection process should be reported in the methods sections of future studies. [ABSTRACT FROM AUTHOR]

The aims were to assess differentiated perceived match exertion and its variability according to playing position for professional soccer players. Nineteen Spanish players declared their respiratory and muscular perceived exertions (PEs) after official matches during an entire season. Players were classified according to their playing position. In order to assess differentiated perceived match exertion, soccer players were asked to assess their perceived level of exertion following each official match. Considerable differences (p<.05; ES=.41 to 2.49) were found between some playing positions but not always in both dimensions of PE (respiratory and muscular). Advanced midfielders (AvMs), wide midfielders (WMs) and wing backs (WnBs) reported the highest match respiratory PE and muscular PE scores. Furthermore, match-to-match differentiated perceived match exertion variability ranged from 12.8 to 27.7% for respiratory perceived exertion and from 11.5 to 25.2% for muscular perceived exertion according to playing position. Match respiratory-muscular PE differences varied among the playing positions, showing higher muscular PE than respiratory PE in central backs (CBs), WMs and central midfielders (CMs) (p<.05; ES=-.35 to .68), but higher respiratory PE than muscular PE in wing backs (p<.05; ES=-.35). Soccer differentiated perceived match exertion is different inter and intra some playing positions, showing large swings for match-to-match variability between playing positions. These facts confirm that the deconstruction of the overall PE provides a more accurate evaluation of the subjective match internal load in some playing positions. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of a different degree of contextual interference (CI) training program on the change of direction ability (CODA) itself and on the straight sprinting (SSP) performance (5 m and 15 m) in students in the first year of primary school. It also evaluated which CI training program was more effective. Eighty eight students (6.42 ± 0.38 yr) volunteered as participants for the present study. Participants were randomized into 5 different CI training programs (LCI: low contextual interference, MCI: moderate contextual interference, HCI: high contextual interference, VCI: variable contextual interference, and CG: control group) during a 3 week period. Significant CODA improvements (p < 0.05) in pre-posttest were found in MCI (4.39%, ES 0.41) and VCI (9.37%, ES 1.12) groups. Furthermore, LCI, MCI and HCI groups ameliorated their SSP performance, both in 5 m (5.92%, ES 0.81; 6.67%, ES 0.90; 8.05%, ES 1.33 respectively) and 15 m SSP (5.86%, ES 0.76; 6.47%, ES 0.80; 2.47% ES 0.41 respectively). These results suggest that training through games of tag (VCI) was the most effective in improving the CODA and training with moderate contextual interference (MCI) was the only type which induced improvements in both capacities (SSP and CODA). [ABSTRACT FROM AUTHOR]

Background: Physical characteristics have been widely analyzed in order to understand why some soccer players are more successful than others. Therefore, the aims of this study were: 1) to describe the evolution of aerobic endurance performance across 18 years in a Spanish elite soccer academy; 2) to know if the playing position could affect physical testing performance; and 3) to look into the alleged impact of this factor on the professional career of soccer players., Methods: We considered 162 players belonging to the reserve team of an elite Spanish soccer club from 1994 to 2012. The percentage of players that played in the reserve team for at least five matches in Third Division (2nd B) and later promoted to the Spanish First or Second Division was 32%. The participants were classified in three six-year periods and according to their highest competitive level attained until the 2014/2015 season and their regular tactical position. All the players performed a four-stage submaximal intermittent running test with the running speeds 12 km/h (10 min), 13 km/h (10 min), 14 km/h (10 min), and 15 km/h (5 min) in order to assess the individual velocities associated with a [La]b of 3 mmol/L (i.e., V3)., Results: No differences (P>0.05) in aerobic fitness were found between the three six-year periods groups (P>0.05), between the tactical positions nor among the competitive levels attained., Conclusions: These findings indicate that aerobic endurance performance (i.e., V3) is not a pertinent trait when identifying players from different seasons, tactical positions and competitive levels.

The purpose of the study was to assess straight sprinting, change of direction ability and horizontal jump performance in youth runners according to age and gender. Two hundred and fifty-five youth runners (116 boys and 139 girls) participated in this study. The athletes were divided according to their age into five groups: under 8 yr (U8), under 10 yr (U10), under 12 yr (U12), under 14 yr (U14) and under 16 yr (U16). Significant differences (p < 0.01) were found between U8 and U10 in the 5 m sprint (d = 1.22), 505 agility test (505, d = 0.96), modified agility test (MAT, d = 1.43), horizontal countermovement jump (HCMJ, d = 1.06) and arm swing HCMJ (HCMJAS, d = 1.44); between U10 and U12 in the 505 (d = 0.39), MAT (d = 0.74), HCMJ (d = 0.96) and HCMJAS (d = 0.75); and between U12 and U14 in 5 m (d = 0.84), HCMJ (d = 0.88) and HCMJAS (d = 0.79). However, no significant differences (p > 0.05, d = 0.29-1.17) between U14 and U16 were observed in any of the tests. With regard to age and gender, in U8 and U10 groups there were no significant differences (p > 0.05, d = 0.02-0.76) between boys and girls in any test. However, in U12 and U14 groups, significant gender differences (p < 0.05, d = 0.85-1.24) were found in the MAT. Likewise, the boys obtained better results than girls in the horizontal jump tests (p < 0.05, d = 1.01-1.26). After the classification by age, some differences were observed between both genders, depending on the fitness variable evaluated.

Background: This is the first study that quantified the anaerobic performance in football players with cerebral palsy (CP)., Objective: This study aimed to examine anaerobic fitness in a population of football players with CP using vertical jumping (VJ) and Wingate tests., Methods: Twelve players (age 26.8 ± 4.8 yr, body mass 66.2 ± 4.8 kg, height 173.7 ± 6.4 cm, body mass index 22.2 ± 1.9 kg m(-2)) from the Spanish National Football Team with CP which had 9.4 ± 3.7 years of playing experience performed the VJ and Wingate anaerobic tests., Results: Vertical jump height was 20.0 ± 1.2 cm for squat jump (HSJ) and 23.9 ± 5.4 cm for countermovement jump (HCMJ). Wingate test peak power (PPOW) was 490.6 ± 125.8 W (7.35 ± 1.53 W kg(-1)). HCMJ was largely (r = -0.631, p = 0.028) and very-largely (r = -0.710, p = 0.01) associated with PPOW (W kg(-1)) and mean power output (MPOW) (W kg(-1)), respectively. Squat jump test peak power (W) showed a large association (r = -0.656, p = 0.021) with MPOW (W and W kg(-1)). The CMJ height resulted 19.5% higher than SJ., Conclusions: Results showed low VJ and anaerobic capacity of football players with CP compared to national players without CP and the general population. In football players with CP the difference (19.5%) between VJ with or without countermovement (CMJ-SJ) was higher than reported for national players without CP. Further studies examining the effect of football practice on neuromuscular performance in subjects with CP are warranted., (Copyright © 2016 Elsevier Inc. All rights reserved.)

The purposes of the study were to assess sprinting and agility performance characteristics and to determine the relationship between these two motor skills in elementary education students. Sprinting and agility performance were assessed in 176 children (88 boys and 88 girls) divided into three groups: Group 1 (G1, N = 98; 48 boys and 50 girls), from the first year of elementary education; Group 2 (G2, N = 38; 15 boys and 23 girls), from the second year of elementary education; Group 3 (G3, N = 40; 25 boys and 15 girls), from the third year of elementary education. Significant differences (p < 0.001) were found in agility ability among the groups and between G1-G3 and G2-G3 in the 5 and 15 m sprint. Regarding gender of the students of the same age, significant differences (p < 0.001) between boys and girls in group G1 and G2 were obtained in the 5 and 15 m sprint. The correlation between agility and acceleration was significant but moderate (0.3 < r < 0.7) in all groups (G1, G2, and G3), in most cases. When the gender factor was included, the results were heterogeneous. Assessing this correlation according to age and gender produced heterogeneous results. For this reason, we think that both are independent qualities and that age and gender are two factors that influence the correlation results.