Description of the Collective Behavior in Competition of Young Soccer Players Under-16 (U-16), Under-17 (U-17), Under-19 (U-19), and Under-23 (U-23), Considering the Areas of the Pitch and Phases of the Game.

ABSTRACT: Nieto, S, Echeazarra, I, Errekagorri, I, and Castellano, J. Description of the collective behavior in competition of young soccer players under-16 (U-16), under-17 (U-17), under-19 (U-19), and under-23 (U-23), considering the areas of the pitch and phases of the game. J Strength Cond Res XX(X): 000-000, 2023-The objective was to employ an integrated observational-notational record to describe collective behavior (CB) in competition matches of young soccer players from 4 teams, U-16, U-17, U-19, and U-23, playing for a professional soccer club academy. A total of 1,481 possessions were registered. Collective behavior, captured by GPS devices, was described with the variables: depth, surface area, stretch index, length, and width. In addition, from the notational analysis, the behavior depending on the area of the field (Z1, Z2, Z3, and Z4) and ball possession (POS), nonball possession (nPOS), and set pieces phases were contextualized. A 2-tailed analysis of variance was applied to compare the CB of the teams. Results show that: (a) in all ages/categories, CB varied significantly in and without the possession of the ball and was conditioned by the area of the pitch where the ball was; (b) CB showed higher values with the ball and greater variability without it; and (c) depending on the age, CB presented differences with larger effect sizes in depth and length, in and without the possession of the ball, in Z1 and Z2. Integrating positional data to the moment of play and areas of the field could help a more accurate analysis of the competition to better understand the CB evolution of young soccer players.

A random forest approach to explore how situational variables affect perceived exertion of elite youth soccer players.

The aim of this study was to explore how situational variables affect youth soccer players' perceived exertion (RPE) after official matches. Thirty-five elite youth male players (14.33 ± 0.86 years; 173.49 ± 6.16 cm; 63.44 ± 5.98 kg) who belonged to two different teams of a professional club participated in this study. Data collection was conducted during two seasons (2016-2017, 2017-2018) and included 60 official matches (30 official matches per team). Ten minutes after each match players rated their RPE and using a modified Borg CR-10 scale. A Random Forest Regression was used to quantify the importance of match-related situational variables in RPE. Afterwards, a linear mixed model analysis was applied to identify the variability in RPE among the situational variables. The game-playing time, the player status (starter or substitute) and the player identity were the strongest predictors of RPE. Moreover, the match outcome and the final scoreline showed significant effects on both starter and substitute players but the main effect of the quality of the opponent was only identified in starter players (p < 0.05). These results allow practitioners to know how situational variables interact and modulate RPE after official matches and help them to prescribe and adapt the players' training content and load before and after matches.

Validation of “TesTactico for F7”: A tool to analyse Declarative Tactical Knowledge based on a Football Competence Observation System / Validación de “TesTactico para F7”: Una herramienta para analizar el Conocimiento Táctico Declarativo basada en un Sistema de Observación de la Competencia Futbolística / Validação do “TesTactico F7”: Um instrumento para analisar o Conhecimento Tático Declarativo baseado em um Sistema de Observação da Competência Futebolística

Este estudio tuvo como objetivo diseñar y validar una prueba de respuesta múltiple con imágenes de situaciones de juego del fútbol para evaluar el conocimiento táctico declarativo (CTD) del jugador. “TesTactico para F7” (fútbol-7) está compuesto por 62 situaciones de juego relacionadas con los criterios (fases, roles, acciones de los subroles adquiridos, principios operacionales y fundamentales/específicos) del Sistema de Observación de la Competencia Futbolística (FOCOS), analizando 67 variables. El coeficiente de validez de contenido (9.63/10) se estimó mediante grupo de expertos (n=13), calculando grado de acuerdo y aceptación. La validez de constructo se calculó mediante la prueba T-Student para muestras independientes. Participaron 155 jóvenes futbolistas organizados según su competencia futbolística (alta=80; baja=75). El cálculo del tamaño de la muestra post-hoc usando G*Power reveló .93 de poder (d=0.5, p=0.5). Se utilizó la corrección de Bonferroni para controlar la tasa de error familiar en cada criterio. Los resultados reflejaron que el grupo de alto nivel fue mejor en las 67 variables, con diferencias significativas (p ≤ .008) en 38 de ellas. También se calculó el tamaño del efecto d-Cohen para evaluar la magnitud de diferencias que fueron grandes (d = 1.38) para el Promedio Total. La fiabilidad de la herramienta se determinó a nivel inter-observador mediante el índice de concordancia kappa de Fleiss (k = .882), y a nivel intra-observador mediante el método test-retest utilizando kappa de Cohen (k = 1.000). La consistencia interna fue estimada a través del coeficiente alfa de Cronbach (α = .925). El análisis de generalizabilidad mostró también una excelente fiabilidad (G =.985) y una representatividad perfecta (r2 = 1.00), evidenciándose que la variabilidad es explicada por las situaciones de juego que componen el test. Se concluye que el instrumento presenta valores óptimos de validez y confiabilidad. (AU)

This study aimed to design and validate a multi-response test with images of football game-play situations to evaluate the player's declarative tactical knowledge (DTK). “TesTactico for F7” (seven-a-side football) is made up of 62 game-play situations related to the criteria (phases, roles, actions of the acquired subroles, operational and core/specific principles) of the Football Competence Observation System (FOCOS), analysing a total of 67 variables. The content validity coefficient (9.63 out of 10) was estimated via expert group (n=13), calculating the averages of the degree of agreement and acceptance of the experts. The construct validity was calculated using Student's T-testfor independent samples. 155 young football players participated according to their football competence (high-level=80; low-level=75). The post-hoc sample size calculation using G*Power revealed .93 of power (d=0.5, p=0.5). Bonferroni correction was used to control the family-wise error rate in each criterion. The results reflected that the high-level group was better in the 67 variables, with significant differences (p ≤ .008) in 38 of them. Cohen’s d-effect size was also calculated to assess the magnitude of the difference between both groups, which were large (d = 1.38) for the Total Average. The reliability of the tool was determined at the inter-observer level using the Fleiss kappa index of concordance (k = .882), and at the intra-observer level through the test-retest method using the Cohen kappa index (k = 1.000). Internal consistency was estimated through Cronbach's alpha coefficient (α = .925). The generalizability analysis also showed excellent reliability (G = .985) and perfect representativeness(r2 = 1.00), showing that the variability is explained by the game-play situations that make up the test. It is concluded that the instrument shows optimal validity and reliability values (AU)

Este estudo teve como objetivo validar um teste de múltipla escolha com imagens de situações de jogo de futebol para avaliar o conhecimento tático declarativo (CTD) do jogador. O "TesTactico F7" (futebol-7) é composto por 62 situações de jogo relacionadas com os critérios do Sistema de Observação da Competência Futebolística (FOCOS), analisando 67 variáveis. O coeficiente de validade de conteúdo (9,63/10) foi estimado por um grupo de especialistas (n=13), calculando o grau de concordância e aceitação. A validade de construto foi calculada usando a T-Student para amostras independentes. Participaram 155 jovens jogadores de futebol, organizados de acordo com sua competência futebolística (alta=80; baixa=75). O cálculo do tamanho da amostra post-hoc usando G*Power revelou poder de 0.93 (d=0.5, p=0.5). A correção de Bonferroni foi usada para controlar a taxa de erro em cada critério. Os resultados mostraram que o grupo de alto nível foi melhor nas 67 variáveis, com diferenças significativas (p ≤ .008) em 38 delas. O tamanho do efeito d-Cohen também foi calculado para avaliar a magnitude das diferenças entre os dois grupos, que foram grandes (d = 1.38) para o Escore Total. A confiabilidade do instrumento foi determinada no nível interobservador pelo índice de concordância Fleiss kappa (k = .882), e no nível intraobservador pelo método teste-reteste usando o kappa de Cohen (k = 1.000). A consistência interna foi estimadapor meio do coeficiente alfa de Cronbach (α = 0,925). A análise de generalização também apresentou excelente confiabilidade (G = .985) e representatividade perfeita (r2 = 1.00), mostrando que a variabilidade é explicada pelas situações de jogo que compõemo teste. Conclui-se que o instrumento apresenta valores ótimos de validade e confiabilidade. (AU)

Análisis de la influencia del marcador en el rendimiento del juego de un equipo de la Tercera División Española de Fútbol: Estudio de caso / Análise da influência do status de partida no desempenho do jogo de uma equipe da Terceira Divisão Espanhola de Futebol: Estudo de caso / Analysis of the influence of the match status on the game performance of a Third Spanish Soccer Division team: Case study

El objetivo del presente estudio fue estudiar cómo afectó el resultado momentáneo del partido en el rendimiento de un equipo perteneciente a la Tercera División Española de Fútbol. Se analizaron los 38 partidos disputados por el equipo de referencia durante la temporada 2018-19. Para valorar el rendimiento del equipo se emplearon los siguientes indicadores de rendimiento: duración de la posesión de balón a favor y en contra en diferentes zonas del terreno de juego, número de finalizaciones a favor y en contra, y de recuperaciones de balón. Los marcadores momentáneos con los que se segmentó el partido fueron: de empatar a ganar (EMGA), de empatar a perder (EMPE), de empatar a mantener (EMMA), de ganar a ampliar (GAAM), de ganar a empatar (GAEM), de ganar a mantener (GAMA), de ganar a reducir (GARE), de perder a ampliar (PEAM), de perder a empatar (PEEM), de perder a mantener (PEMA) y de perder a reducir (PERE). Se realizó la prueba no paramétrica U de Mann-Whitney para comparar los 11 tipos de marcadores dos a dos(p<0,05). El principal resultado del estudio fue que el equipo jugó diferente en función del estado del marcador momentáneo. El estudio sugiere a los entrenadores de fútbol amateur que además de tratar de desarrollar un modelo de juego particular, deberían atender estrategias de trabajo donde se planteen escenarios diversos en relación al resultado momentáneo. (AU)

The purpose of this study was to study how the match status of the match affected the performance of a team belonging to the Spanish Third Division of Soccer. The 38 games played by the reference team were analysed during 2018-19 season. In order to assessthe team's performance, the following performance indicators were used: duration of ball possession for and against in different zones of the pitch of play, number of shots for and against, and ball recoveries. The momentary scores with which the match was segmented were: from drawing to winning (EMGA), from drawing to losing (EMPE), from drawing to maintaining (EMMA), from winning to increasing (GAAM), from winning to drawing (GAEM), from winning to maintaining (GAMA), from winning to reducing (GARE), from losing to increasing (PEAM), from losing to drawing (PEEM), from losing to maintaining (PEMA) and from losing to reducing (PERE). The non-parametric Mann-Whitney U test was performed to compare the 11 types of scores two by two (p<0.05). The main result of the study was that the team played differently depending on the state of the momentary score. The study suggests to amateur soccer coaches that in addition to trying to develop a particular game model, they should attend to work strategies where different scenarios are considered in relation to the match status. (AU)

O objetivo deste estudo foi estudar como o status do jogo afetou o desempenho de uma equipe pertencente à Terceira Divisão Espanhola de Futebol. Foram analisados os 38 jogos disputados pela equipa de referência durante a época 2018-19. Para avaliar o desempenho da equipe, foram utilizados os seguintes indicadores de desempenho: duração da posse de bola a favor e contra em diferentes áreas do campo de jogo, número de chutes a favor e contra e recuperações de bola. As pontuações momentâneas com as quais a partida foi segmentada foram: do empate à vitória (EMGA), do empate à derrota (EMPE), do empate à manutenção (EMMA), da vitória ao aumento (GAAM), da vitória ao empate (GAEM), de ganhar para manter (GAMA), de ganhar para reduzir (GARE), de perder para aumentar (PEAM), de perder para empatar (PEEM), de perder para manter (PEMA) e de perder para reduzir (PERE). O teste não paramétrico U de Mann-Whitneyfoi realizado para comparar os 11 tipos de escores dois a dois (p<0,05). O principal resultado do estudo foi que a equipe jogou de forma diferente dependendo do estado da pontuação momentânea. O estudo sugere aos treinadores de futebol amador que, além de tentarem desenvolver um determinado modelo de jogo, atendam a estratégias de trabalho onde sejam consideradosdiferentes cenários em relação ao status da partida. (AU)

Tell me how and where you play football and I'll tell you how much you have to run.

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 km·h-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.

A longitudinal analysis of technical-tactical and physical performance of the teams in the Spanish LaLiga Santander: An eight-season study.

The aim of this study was to describe in the way teams played for the last eight seasons (from 2011-12 to 2018-19) in the Spanish Football First Division (Spanish LaLiga Santander), taking into account team match performances (n = 5,518). Ten technical-tactical and physical variables grouped into five dimensions were used: final behaviour (shots and crosses), set piece (corners and fouls), match volume (passes), physical performance (total distance covered) and collective use of the space (team width, team length, team defence height and distance from the goalkeeper to their defence). The main results were that the number of passes and team width showed a stable trend as the seasons passed. Nevertheless, the number of shots, crosses and corners, total distance covered, team length and distance from the goalkeeper to their defence showed a descending trend. The main conclusion was that over the seasons studied, the Spanish LaLiga Santander teams were characterized by an indirect style of play that, being the usual in this league, presented some evolution. The trend in the evolution of the game is that defence is put before attack. The findings of the study may be of interest to professional football staff to know more about the particular way teams play in competition, as well as its evolution, so as to focus on the training process according to the trend that is taking place in the game.

Evaluating Physical and Tactical Performance and Their Connection during Female Soccer Matches Using Global Positioning Systems.

The objective of the present study was to evaluate the tactical and physical performance during official matches of a women's soccer league and to correlate both dimensions in periods of 15 min. To do this, eight official matches of a semi-professional soccer team belonging to the Women's Second Division of Spain (Reto Iberdrola) were analysed during the 2020-2021 season. The variables recorded were classified into two dimensions: tactical variables (i.e., Width, Length, Height and Surface Area) and physical variables (i.e., Total Distance Covered (TD), Total Distance Covered in High-Speed Running (HSR) and Total Distance Covered in Sprint). The main results were: (1) there were no differences between the periods in any of the tactical dimension variables; (2) in the physical dimension, a significant decrease in TD and HSR was described at the end of the match (period 60-75); and (3) some positive correlations were found among some variables of the tactical and physical dimension at the beginning and at the end of the match (periods 0-15, 60-75 and 75-90). The findings of the study suggest that connecting the tactical and physical dimension in the interpretation of team performance would allow for a better understanding of player and team performance and during competition.

Selecting Training-Load Measures to Explain Variability in Football Training Games.

The purpose of this study was to investigate the structure of interrelationships among external (eT) and internal (iT) training intensity metrics and how these vary depending on game format in soccer. The variables were collected from 16 semi-professional players in seven types of small, medium, large-sided, and simulated games (SG). The eT variables were (per min): peak velocity (Vmax), total distance (DTmin), distance covered at velocities less than 60% (D < 60%min), between 60 and 80% (D > 60%min), and more than 80% (D > 80%min) of the maximal velocity, player load (PLmin), and distance covered accelerating at more than 2 m⋅s-2 (Daccmin) and decelerating at less than -2 m⋅s-2 (Ddecmin). The iT variables were: Edwards arbitrary units (EDWmin) and time spent at more than 80% of the maximal heart rate (T > 80% HRmin). All game formats were represented by three principal components (PC), explaining from 66.9 to 76.0% of the variance. The structure of the interrelationships among variables involved similar distributions in the PCs that are related to energetic production systems, such as the strength/neuromuscular dimension (PLmin and/or Daccmin and Ddecmin, complemented by DTmin and D < 60%min), the endurance/cardiovascular dimension (EDWmin), and the velocity/locomotion dimension (Vmax, D > 60%min, or D > 80%min). A particular combination of external and internal intensity measures is required to describe the training load of game formats.

Influence of pitch length on inter- and intra-team behaviors in youth soccer / Influencia de la longitud del campo en los comportamientos inter e intra -equipo en jóvenes jugadores de fútbol

Tactical behavior could be affected by changes in small-sided game (SSG) formats. The aim of the present study was to analyze the influence of different pitch lengths during 7-a-side SSGs played by young football players. Fourteen male soccer players in each age group (13 and 14 years old, U13 and U14 teams) were divided in two teams of seven players who played four SSGs of 7 minutes, interspersed with 4 minutes of passive recovery. The only modification to the SSG format was pitch length: 60 m (SSG60), 50 m (SSG50), 40 m (SSG40), and 30 m (SSG30), while the width of the field was kept constant at 40 m. The variables used to characterize collective behavior were grouped in a) intra-team variables, namely, team length (L), team width (W), effective area of team play or convex hull (CH), and stretch index (SI); and b) inter-team variables, namely distance between centroids (DC), length of both teams (L2), width of both teams (W2), convex hull of both teams (CH2), and stretch index of both teams (SI2). Our results revealed different intra and inter-team behaviors according to SSG format and player age. L, CH, SI, DC, L2, CH2, and SI2 all increased with increasing pitch length, while W and W2 showed only minimal changes. The differences were greater in the U13 group, suggesting that younger players were more likely to vary their collective behavior in response to changes to pitch length, inter-task, particularly in the longer pitches (SSG50 and SSG60). Conversely, using the analysis of the entropy, greater unpredictability of tactical behavior was observed in the U14 group, intra-task, compared with the U13 group. Overall, the findings suggest that responses to task constraints, such as modifications to pitch length and accordingly relative area of play, are dependent on age (experience, skill) and this is something coaches should consider when designing SSGs to develop team tactics (AU)

El comportamiento táctico puede verse afectado por los cambios en los formatos de juegos reducidos (SSG). El objetivo del presente estudio fue analizar la influencia de diferentes longitudes del terreno de juego en formatos SSG-de-7 jugadores en jóvenes futbolistas. 14 jugadores masculinos de fútbol en cada grupo de edad (13 y 14 años, U13 y U14, respectivamente) se dividieron en dos equipos de siete jugadores, quienes jugaron en cuatro SSGs de 7 minutos de duración, intercalados con 4 minutos de recuperación pasiva. La única modificación en el formato SSG fue longitud del terreno: 60 m (SSG60), 50 m (SSG50), 40 m (SSG40) y 30 m (SSG30), mientras que la anchura del campo de 40 m se mantuvo constante. Las variables utilizadas para caracterizar el comportamiento colectivo se agruparon en: a) variables intra-equipo, es decir, la longitud del equipo (L), ancho del equipo (W), el área efectiva de juego del equipo o convex hull (CH), y el strech index (SI); y b) las variables inter-equipo, es decir, la distancia entre los centroides (DC), la longitud de los dos equipos (L2), la anchura de los dos equipos (W2), envolvente convexa de los dos equipos (CH2), y el índice de estiramiento de los dos equipos (SI2). Los resultados revelan diferentes comportamientos intra e inter-equipo de acuerdo al formato de SSG y la edad del jugador. Las variables L, CH, SI, DC, L2, CH2, y SI2 aumentaron con el incremento en longitud del terreno, mientras que W y W2 mostraron sólo cambios mínimos. Las diferencias fueron mayores en el grupo U13, lo que sugiere que los jugadores más jóvenes fueron más propensos a variar su comportamiento colectivo en respuesta a los cambios de alargar el terreno de juego, inter-tarea, especilamente en los campos más largos (SSG50 y SSG60). Por el contrario, utilizando el análisis de la entropía, mayor imprevisibilidad de comportamiento del equipo se observó en el grupo U14, intra-tarea, en comparación con el grupo U13. En general, los resultados sugieren que las respuestas a la limitación de las tareas, tales como la modificación de la longitud del espacio y el espacio relativo de juego, son dependientes de la edad (experiencia, habilidad) y esto es algo que los entrenadores deben tener en cuenta al diseñar los SSGs para desarrollar comportameintos tácticos colectivos (AU)

Absolute and Relative Training Load and Its Relation to Fatigue in Football.

The aim of the study was to assess the relationship of external and internal training load (TL) indicators with the objective and subjective fatigue experienced by 15 semi-professional football players, over eight complete weeks of the competition period in the 2015-2016 season, which covered microcycles from 34th to 41st. The maximum heart rate (HRmax) and maximum speed (Vmax) of all the players were previously measured in specific tests. The TL was monitored via questionnaires on rating of perceived exertion (RPE), pulsometers and GPS devices, registering the variables: total distance (TD), player load 2D (PL2D), TD at >80% of the Vmax (TD80), TD in deceleration at < -2 m⋅sec-2 (TDD <-2), TD in acceleration >2 m⋅sec-2 (TDA >2), Edwards (ED), time spent at between 50 and 80% (50-80% HRmax), 80-90% (80-90% HRmax), and >90% of the HRmax (>90% HRmax), and RPE both respiratory/thoracic (RPEres) and leg/muscular (RPEmus). All the variables were analyzed taking into account both the absolute values accumulated over the week and the normalized values in relation to individual mean competition values. Neuromuscular fatigue was measured objectively using the countermovement jump test and subjectively via the Total Quality Recovery (TQR) scale questionnaire. Analytical correlation techniques were later applied within the general linear model. There is a correlation between the fatigue experienced by the player, assessed objectively and subjectively, and the load accumulated over the week, this being assessed in absolute and relative terms. Specifically, the load relative to competition correlated with the physical variables TD (-0.279), PL2D (-0.272), TDD < -2 (-0.294), TDA >2 (-0.309), and sRPEmus (-0.287). The variables related to heart rate produced a higher correlation with TQR. There is a correlation between objectively and subjectively assessed fatigue and the accumulated TL of a player over the week, with a higher sensitivity being shown when compared to the values related to the demands of competition. Monitoring load and assessing fatigue, we are closer to knowing what the prescription of an adequate dose of training should be in order for a player to be as fresh as possible and in top condition for a match. Normalizing training demands with respect to competition could be an appropriate strategy for individualizing player TL.

Number of Players and Relative Pitch Area per Player: Comparing Their Influence on Heart Rate and Physical Demands in Under-12 and Under-13 Football Players.

The aim of the present study is to analyse the influence of different large-sided games (LSGs) on the physical and physiological variables in under-12s (U12) and -13s (U13) soccer players. The effects of the combination of different number of players per team, 7, 9, and 11 (P7, P9, and P11, respectively) with three relative pitch areas, 100, 200, and 300 m(2) (A100, A200, and A300, respectively), were analysed in this study. The variables analysed were: 1) global indicator such as total distance (TD); work:rest ratio (W:R); player-load (PL) and maximal speed (Vmax); 2) heart rate (HR) mean and time spent in different intensity zones of HR (<75%, 75-84%, 84-90% and >90%), and; 3) five absolute (<8, 8-13, 13-16 and >16 Km h(-1)) and three relative speed categories (<40%, 40-60% and >60% Vmax). The results support the theory that a change in format (player number and pitch dimensions) affects no similarly in the two players categories. Although it can seem that U13 players are more demanded in this kind of LSG, when the work load is assessed from a relative point of view, great pitch dimensions and/or high number of player per team are involved in the training task to the U12 players. The results of this study could alert to the coaches to avoid some types of LSGs for the U12 players such as: P11 played in A100, A200 or A300, P9 played in A200 or A300 and P7 played in A300 due to that U13>U12 in several physical and physiological variables (W:R, time spent in 84-90%HRmax, distance in 8-13 and 13-16 Km h(-1) and time spent in 40-60%Vmax). These results may help youth soccer coaches to plan the progressive introduction of LSGs so that task demands are adapted to the physiological and physical development of participants.

Influence of the number of players and the relative pitch area per player on heart rate and physical demands in youth soccer.

The aim of this study was to analyze the influence of different large-sided games on the physical and physiological variables in under-13 soccer players. The effects on heart rate (HR) and physical demands of different number of players (NP) (7, 9, and 11) together with the relative pitch area (RPA) (100, 200, and 300 m) during two 12-minute repetitions were analyzed in this study. The variables analyzed were mean, maximum and different intensity zones of HR; total distance (TD); work:rest ratio (W:R); player load (PL); 5 absolute and 3 relative speed categories. The results support the hypothesis that a change in pitch dimensions affects locomotor activity more than the NP does but also refute the hypothesis that the change in the NP has a greater effect on HR. To be more specific, an increase in the RPA per player (300/200/100 m2) was associated with higher values of the following variables: TD (2,250-2,314/2,003-2,148/1,766-1,845 m), W:R (0.5-0.6/0.4-0.5/0.3 arbitrary unit [AU]), PL (271-306/246-285/229-267 AU), %HRmean (85-88/85-89/81-83%), %HRmax (95-100/97-100/95-98%), and affected the percentage of time spent in both absolute (above 8 km·h(-1)) and relative speed (above 40% Vmax) categories (p ≤ 0.05, effect size: 0.31-0.85). These results may help youth soccer coaches to plan the progressive introduction of large-sided games so that task demands are adapted to the physiological and physical development of participants.