CHANGES IN JUMP AND SPRINT PERFORMANCES DURING 14 PRESEASONS IN A SPANISH RESERVE ELITE SOCCER TEAM

The aim of this study was to assess the changes in jump and sprint performances after the preseason period across 14 seasons depending on the initial performance level and the playing position in young professional soccer players. In total, 162 soccer players (age = 20.6 ± 1.8 years) belonging to the same reserve team of a Spanish La Liga club participated in this study. Countermovement jump (CMJ) and 5 and 15 m sprints were assessed in each season at the start of the preseason (July), Test 1 (T1), and the start of the competitive period (September), Test 2 (T2), from the 1998 to 2013 seasons. Considering all seasons, a trivial change was found in the sprint (5 m, Effect Size [ES] = −0.01; ±0.11, most-likely; and 15 m, ES = 0.05; ±0.09, most-likely) and countermovement jump (CMJ) performances (ES = −0.03; ±0.07; most-likely) after the preseason, but this varied across the seasons. While the fastest players in 5 m and 15 m tests and the most powerful worsened their performances in sprinting capacity (ES = 0.53–0.65, small very-likely) and in jump ability (ES = −0.54; ±0.25, small very-likely), respectively, the slowest players and the less powerful improved their performance likely/most-likely (ES = −0.33 and −0.68, small and moderate) and very-likely (ES = 0.40; ±0.20, small) after the precompetitive period. The changes in CMJ and sprinting were trivial and trivial/small for all tactical positions. The changes in neuromuscular performance after the preseason were not stable across the seasons and varied depending on the initial performance level. Individualization strategies should be considered in the design of strength and conditioning programs in order to optimize the training process

Physical fitness performance, playing position and competitive level attained by elite junior soccer players: a 12-year study

The aim of this study was to look into the alleged impact of the physical fitness performance of elite junior soccer players on the professional career according to playing position. The physical tests (sprint test, countermovement jump [CMJ], and maximal aerobic speed [MAS]) performed by 165 players enrolled in the junior team of a Spanish 1st Division club (1998-2010) were evaluated. Players were classified as those who were promoted to the reserve team (Reserve Team) and those who were not (non-Reserve Team), and as those who were promoted to the Spanish 1st/2nd Divisions (PFL) and those who were not (NPFL) until the 2020-2021 season. Overall, no significant differences (p>.05) were found between the Reserve Team and non-Reserve Team or between the PFL and NPFL players in neuromuscular performance. Aerobic fitness was greater (p<.05; ES = .79 ± .60, moderate; mean difference = 3.0%) for the Reserve Team lateral midfielders in comparison to that for the non-Reserve Team. The results suggest that the impact of physical fitness on the promotion of elite junior soccer players is limited

Evaluación de la efectividad de distintos programas motores basados en la interferencia contextual en estudiantes de educación primaria

El objetivo de este estudio fue analizar los efectos de distintos programas de intervención, aplicados en las clases de educación física y basados en la interferencia contextual (IC), en niños y niñas de tercer curso de educación primaria (9-10 años). 70 niños (35 chicos y 35 chicas) de un colegio público, que cursaban el tercer curso de educación primaria, participaron en el estudio. Los alumnos fueron divididos en cuatro grupos en función del tipo de programa de IC a realizar, siendo testada su capacidad de cambiar de dirección (Modified Agility Test, MAT) y aceleración (tiempo en el sprint de 5 y 15 m) antes y después de las 5 semanas de intervención. Se encontraron diferencias significativas en la capacidad de cambiar de dirección entre el pretest y el postest en el grupo IC baja, en el grupo IC moderada y en el grupo IC variable y no ocurrió lo mismo con el grupo IC alta. Únicamente el grupo de IC baja mostró diferencias significativas entre el pretest y el postest en el sprint de 5 m y ninguno de los programas fue efectivo en la capacidad de aceleración de 15 m. Las características o rasgos de los programas de intervención basados en el nivel de interferencia contextual condicionaron los efectos producidos en la capacidad de aceleración y en el cambio de dirección.The purpose of this study was to analyse the effects of different intervention programmes, applied in physical education classes and based on contextual interference (CI), in children in their 3rd year of primary education (9-10 years). Seventy children (35 boys and 35 girls) from a state school, who were in their third year of primary education, took part in the study. The school children were divided into four groups depending on the type of CI programme they were going to carry out. Their capacity to change direction (Modified Agility Test MAT) and acceleration capacity (time for a 5m and 15m sprint) were tested before and after the 5 week intervention. Significant differences were found in capacity to change direction capacity between the pre-test and post-test in the low CI group, the moderate CI group and the variable CI group, but not in the high CI group. Only the low CI group showed significant differences between the pre test and post-test in the 5m sprint and none of the programmes were effective on acceleration capacity in the 15m sprint. The features or characteristics of the intervention programmes based on the level of contextual interference conditioned the effects produced on acceleration and capacity to change direction.O objectivo deste estudo foi analisar os efeitos de distintos programas de intervenção, aplicados em aulas de educação física e baseados na interferência contextual (IC), em rapazes e raparigas do terceiro ano de educação primária (9-10 anos). 70 crianças (35 rapazes e 35 raparigas) de uma escola pública, que frequentavam o terceiro ano de educação primária, participaram no estudo. Os alunos foram divididos em quatro grupos em função do tipo de programa de IC a realizar, sendo testada a sua capacidade para mudar de direcção (Modified Agility Test, MAT) e aceleração (tempo em sprint de 5 e 15 m) antes e depois das 5 semanas de intervenção. Foram encontradas diferenças significativas na capacidade de mudar de direcção entre o pré- teste e o pós-teste no grupo de IC baixa, no grupo IC moderada e no grupo IC variável, não ocorrendo o mesmo com o grupo IC alta. Unicamente o grupo de IC baixa revelou diferenças significativas entre o pré-teste e o pós-teste no sprint de 5 m e nenhum dos programas foi efectivo na capacidade de aceleração de 15 m. As características ou traços dos programas de intervenção baseados no nível de interferência contextual condicionaram os efeitos produzidos na capacidade de aceleração e na mudança de direção

DIFFERENTIATED PERCEIVED MATCH LOAD AND ITS VARIABILITY ACCORDING TO PLAYING POSITION IN PROFESSIONAL SOCCER PLAYERS DURING AN ENTIRE SEASON

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

Factors of disagreement between coaches and players of a high-level basketball team when assessing individual session perceived exertions

The main objective of this study was to evaluate the concordance between the coaches and the players of a Spanish highlevel female basketball team when evaluating the hardness of practice sessions looking into the factors that could modulate the alleged biases of the coaches. The three staff members severely underestimated the players' session perceived exertion, which meant that, as a group, they were not capable of planning the desired intensity along the registered period. Furthermore, this study allowed us to detect what aspects of coaching knowledge should deserve more attention with each staff members if we desired less biased judgments about the players' perceptions, who were the most relevant and common source of bias.El principal objetivo de este estudio fue evaluar la concordancia entre los entrenadores y los jugadores de un equipo femenino español al valorar la dureza de las sesiones de entrenamiento, prestando especial atención a los factores moduladores de los posibles sesgos en el cuerpo técnico. Los tres entrenadores infravaloraban notablemente los valores de fatiga declarados por los jugadores tras las sesiones, lo que implicaba que, en conjunto, no eran capaces de planificar correctamente la intensidad del ejercicio propuesto en cada periodo. En este sentido, esta investigación nos permitió detectar en qué aspectos del pensamiento de cada entrenador se debía incidir para reducir sus sesgos particulares y el más común entre los tres: los jugadores mismos

Variability of the Motor Behavior during Continued Practice of the Same Motor Game: A Preliminary Study

Motor behavior assessment during games could help physical education teachers and team coaches to design effective and efficient motor interventions. This study aimed to assess the variability of the physical and behavioral responses during continued practice of the game tail tag with a ball. Sixteen Spanish youth soccer players from an under-14 team played tail tag, with a ball, during four sessions (5 repetitions of 1 min per session). Physical (i.e., Total Distance (TD) and PlayerLoad (PL)) and behavioral (i.e., Surface Area (SA) and change in the Geometrical Centre position (cGCp)) dimensions were assessed with a local positioning system. The mean of the five series of each session was considered for further statistical analysis. The main finding was that the external load decreased (d = small − large) and the use of space varied during the continued practice of tail tag. Initially, SA increased substantially (d = large) and cGCp decreased slightly (d = small), and then both variables tended to stabilize. This suggests that after several repetitions of the same motor game, physical education teachers and team sports coaches should use this again later, modifying this or proposing new motor games where players respond to these activities that consist in greater uncertainty than to well-known motor games.The authors gratefully acknowledge the support of a Spanish government subproject Integration ways between qualitative and quantitative data, multiple case development, and synthesis review as main axis for an innovative future in physical activity and sports research [PGC2018-098742-B-C31] (Ministerio de Ciencia, Innovación y Universidades, Programa Estatal de Generación de Conocimiento y Fortalecimiento Científico y Tecnológico del Sistema I + D + i), that is part of the coordinated project New approach of research in physical activity and sport from mixed methods perspective (NARPAS_MM) [SPGC201800X098742CV0]

Assessing the Anthropometric Profile of Spanish Elite Reserve Soccer Players by Playing Position over a Decade

The aims of this study were to describe the evolution of the anthropometric profile of soccer players over a decade and to compare the anthropometric profiles of players promoted from an elite reserve team to high-level soccer with those players who were not promoted. We examined the body mass, height, body-mass index, and body fat of 98 players enrolled in the reserve team from 2008 to 2018. The players were classified in terms of (a) the highest competitive level they achieved up to the 2019/2020 season (i.e., Spanish 1st–2nd divisions or semi-professional); (b) the period in which they played their last season on the team; and (c) their playing position. Over time, the height of goalkeepers, lateral midfielders, and attackers has increased (effect size = 0.66 ± 1.13) but has decreased in central midfielders (effect size = 0.83). The body fat of defenders has also fallen (effect size = 0.55 ± 0.95). Spanish high-level goalkeepers, lateral midfielders, and attackers were taller than their semi-professional player counterparts (effect size = 1.20 ± 1.98). Body fat did not determine promotion from a reserve team to high-level soccer, but height may be an advantage for several playing positions. The assessment of the anthropometric profile and the application of interventions should be designed according to the playing position.The authors gratefully acknowledge the support of the Spanish government’s subproject Integration paths between qualitative and quantitative data, multiple case development, and synthesis review as the main axis for an innovative future in physical activity and sports research [PGC2018-098742-B-C31] (Ministerio de Ciencia, Innovación y Universidades, Programa Estatal de Generación de Conocimiento y Fortalecimiento Científico y Tecnológico del Sistema I+D+i), which is part of the coordinated project’s new approach towards research in physical activity and sport from a mixed-methods perspective (NARPAS_MM) [SPGC201800X098742CV0]

JUMP LANDING CHARACTERISTICS IN ELITE SOCCER PLAYERS WITH CEREBRAL PALSY

The aim of the present study was to analyse the parameters that characterize the vertical ground reaction force during the landing phase of a jump, and to determine the relationship among these parameters in elite soccer players with cerebral palsy (CP). Thirteen male members of the Spanish national soccer team for people with CP (mean age: 27.1 ± 4.7 years) volunteered for the study. Each participant performed three counter movement jumps. The characteristics of the first peak of the vertical ground reaction force during the landing phase of a jump, which corresponds to the forefoot contact with the ground, were similar to the results obtained in previous studies. However, a higher magnitude of rearfoot contact with the ground (F2) was observed in participants with CP than in participants without CP. Furthermore, a significant correlation between F2 magnitude and the elapsed time until its production (T2) was not observed (r = -0.474 for p = 0.102). This result implies that a landing technique based on a delay in the production of F2 might not be effective to reduce its magnitude, contrary to what has been observed in participants without CP. The absence of a significant correlation between these two parameters in the present study, and the high magnitude of F2, suggest that elite soccer players with CP should use footwear with proper cushioning characteristics

Specificity of jumping, acceleration and quick change of direction motor abilities in soccer players

The purpose of this study was to determine the underlying structure of stretch-shortening cycle (SSC) jumping, acceleration and change-of-direction (COD) abilities in soccer players using principal component factor analysis (PCA). Based on the results of recent studies on male college athletes, we hypothesized that slow SSC jumping, acceleration and COD represent independent motor abilities in soccer players. Forty two soccer players (23.2±2.36 yr) performed three tests for each group of rapid lower-body movements: a) three vertical slow SSC jumping tests - squat jump (SJ), countermovement jump (CMJ) and arm swing countermovement jump (CMJAS), b) three acceleration tests - 5, 10 and 15 meter sprint times (ACC5, ACC10 and ACC15), and c) three COD tests - modified agility test free (MATF), the 505 agility test (505) and 20 yard agility test (Y20). PCA was applied to establish the relationships among the factors (i.e. the motor abilities) underlying the included manifest variables (i.e. the performance tests). This procedure reduced all variables to a smaller number of independent latent dimensions. The results indicated three separate factors that may correspond to slow SSC jumping, acceleration and COD abilities. The magnitude of the correlation coefficients among the three motor abilities extracted was r<.56. Therefore, it is suggested that slow SSC jumping, acceleration and COD abilities represent independent motor abilities and consequently these should be trained and evaluated separately to assess soccer players’ physical profiles

In-season training periodization of professional soccer players

The aim of this study was to quantify the seasonal perceived respiratory and muscular training loads (i.e., sRPEres-TL and sRPEmus-TL) completed by elite-oriented young professional soccer players. Twenty four players (20.3 +/- 2.0 years) belonging to the same reserve team of a Spanish La Liga club participated in this study. Only the players that were available to train for a whole week with the team and also to play the weekly game were considered: Starters, players that participated in the match for at least 45 min and NonStarters, players that did not participate or played less than 45 minutes in the match. The competitive period was analysed after the division into 5x6-8 week blocks and 35x1 week microcycles. Data were also analysed with respect to number of days before the immediate match. Weekly TL variation across the in-season blocks was trivial-small for both groups except between Block 2 and Block 3 (ES= moderate). Substantial TL differences (ES= small-very likely) were found between training days, the TL pattern being a progressive increase up to MD-3 followed by a decrease until MD-1. Except for the match, sRPEres-/sRPEmus-TL was very similar between Starters and Non-Starters. In summary, perceived TL across the season displayed limited variation. Coaches periodized training contents to attain the highest weekly TL 72 hours before the match to progressively unload the players between MD-3 and the match day. The data revealed that the TL arising from the weekly game was solely responsible for the observed higher weekly TL of Starters in comparison with Non-Starters