Variables In Soccer Players Research Articles

Career path clustering of elite soccer players among European Big-5 nations utilizing Dynamic Time Warping

Abstract Prior clustering approaches of soccer players have employed a variety of methods based on various data categories, but none of them have focused on clustering by career paths characterized through a time series analysis of yearly performance quality. Therefore, this study aims to propose a methodology how a career path can be represented as a time series of a player’s seasonal qualities and then be clustered with players that have a similar career path. The underlying data focuses on soccer players from the five largest European soccer nations (Big-5). This allows for the identification of different types of career paths of players and the investigation of significant disparities between career paths among the Big-5 nations. In line with our proposed methodological approach, we identified and interpreted 13 different clusters of player career paths. These range from the cluster with the highest player quality scores to the pattern comprising players with the weakest scores. Further, the detected clusters show significant differences regarding variables of soccer players’ early career phase in adolescence (e.g., age of debut in professional soccer, years spent in a youth academy). The presented approach might represent a first step for stakeholders in soccer to get an objective insight in players’ career by utilizing mainly freely available data sources.

Predictive Strength of Contextual and Personal Variables in Soccer Players' Goal Orientations.

Psychological variables, such as perceived motivational climate, goal orientation, self-determined motivation, and personality, have an influence on sports success performance. This study aimed to examine the relationships among a set of psychological variables (perceived motivational climate, goal orientation, self-determined motivation, and personality) in male and female footballers. Participants were 167 footballers (106 male, 61 female), aged 12 to 26, competing with clubs in the Spanish Football League. They all took four questionnaires aimed at evaluating motivational climate, goal orientations, self-determined motivation, and personality. The analyses of correlation and regression showed statistically significant relations among the variables. Neuroticism and psychoticism negatively relate to mastery motivational climate, the best predictor of self-determined motivation. It was concluded that contextual variables carry more weight in predicting goal orientations and self-determined motivation among participant footballers.

The Effect of External Focus Attention Exercise On the Kinetic Risk Factors Associated With ACL Injury

Background and Aims One of the most common and dangerous injuries in sports is an Anterior Cruciate Ligament (ACL) injury. Today, despite the ACL injury prevention programs, the prevalence of this injury remains high. Most of the instructions used in injury prevention programs are based on internal focus, while studies have shown that using external focus can improve performance in individuals. The purpose of this study was to investigate the effect of focus of attention on eight weeks of anterior cruciate ligament injury prevention training on landing skill kinetic variables in soccer players. Methods The current methodology included 35 players from 3 premier league teams in Tehran province. The teams were randomly divided into three groups of Prevent injury and Enhance Performance (PEP) exercises based on the External Focus (EF) (12 people), Internal Focus (IF) (12 people), and control group (11 people). In the pretest of ground reaction force, rate of loading, and time to stabilization during landing skill. The training groups performed pep injury prevention exercises for eight weeks and related instructions instead of warm-up exercises. Control group players were performing the regular activities. ANOVA with repeated measures and one-way ANOVA and Tukey post hoc tests were used to evaluate changes Results The test results showed significant changes in vertical, anterior-posterior ground reaction force and rate of loading in the external focus group (P≤0.05). But there was no critical difference in time to stabilization and internal-external ground reaction force. Conclusion According to the results, external focus instruction has positive effects on kinetic components. Therefore, it is recommended that exercises based on these instructions be used to reduce the risk of ACL injury and to repair this injury.

Match-running performance of young soccer players in different game formats

ABSTRACTPresent study aimed to analyse the effect of game format, age-group, and playing position on match-running variables of soccer players (age ranging from 6.94 ± 0.7 to 13.46 ± 0.5 years; height ranging from 125.36 ± 6.04 to 159.16 ± 7.78 cm; weight ranging from 27.16 ± 5.75 to 49.89 ± 8.89 kgf). Match-running variables were assessed using global positioning system technology. Results suggest that game formats, which include more players have a significant effect on match-running variables than those having fewer players (p < 0.001). Moreover, oldest age-groups covered significantly higher distances in all categories than younger groups, total distance (TD): η2 = 0.32, p < 0.001; low-intensity running (LIR): η2 = 0.09, p < 0.001; high-intensity running (HIR): η2 = 0.25, p < 0.001; very high-intensity running (VHIR): η2 = 0.34, p < 0.001; very high-intensity activity (VHIA): η2 = 0.42, p < 0.001; and sprinting (SP): η2 = 0.41, p < 0.001). Match-running variables also differ among playing positions. Defenders covered lowest TD and HIR in all age-groups; midfielders covered highest TD and LIR in all age-groups (p < 0.001); forwards covered highest VHIR, VHIA, and SP in U14 age-group. Defenders covered lowest TD, LIR, HIR, and VHIR; midfielders covered highest TD and HIR regardless game format (p < 0.001); forwards covered highest VHIR, VHIA, and SP in 11v11 format (p < 0.001). These findings can provide an opportunity for coaches to maximise the efficiency of their training sessions.

The Reliability and Validity of a Soccer-Specific Nonmotorised Treadmill Simulation (Intermittent Soccer Performance Test)

This study investigated the reliability and validity of a novel nonmotorised treadmill (NMT)-based soccer simulation using a novel activity category called a "variable run" to quantify fatigue during high-speed running. Twelve male University soccer players completed 3 familiarization sessions and 1 peak speed assessment before completing the intermittent soccer performance test (iSPT) twice. The 2 iSPTs were separated by 6-10 days. The total distance, sprint distance, and high-speed running distance (HSD) were 8,968 ± 430 m, 980 ± 75 m and 2,122 ± 140 m, respectively. No significant difference (p > 0.05) was found between repeated trials of the iSPT for all physiological and performance variables. Reliability measures between iSPT1 and iSPT2 showed good agreement (coefficient of variation: <4.6%; intraclass correlation coefficient: >0.80). Furthermore, the variable run phase showed HSD significantly decreased (p ≤ 0.05) in the last 15 minutes (89 ± 6 m) compared with the first 15 minutes (85 ± 7 m), quantifying decrements in high-speed exercise compared with the previous literature. This study validates the iSPT as a NMT-based soccer simulation compared with the previous match-play data and is a reliable tool for assessing and monitoring physiological and performance variables in soccer players. The iSPT could be used in a number of ways including player rehabilitation, understanding the efficacy of nutritional interventions, and also the quantification of environmentally mediated decrements on soccer-specific performance.

A Pre-season Comparison of Aerobic Fitness and Flexibility of Younger and Older Professional Soccer Players

Aerobic fitness and flexibility generally present age-related decreases, yet the influence of age on these variables in soccer players is still unknown. We obtained oxygen consumption (VO(2)) and heart rate (HR) at 12 km · h (- 1), anaerobic threshold and maximum intensities, and athletes' flexibility profiles using Flexitest (FLX). Pre-season data (2005-2011) from the 2 extreme age terciles (n=54) - YOUNGER (17-22 years old) and OLDER (27-36 years old) - of a group of 162 players from an elite Brazilian soccer club were compared. The effects of aging were also assessed by contrasting VO(2), HR and FLX linear regressions - slope and intercept - vs. age-predicted and reference values. The results were similar between the YOUNGER and OLDER terciles for VO(2max), at 62.7 ± 6.1 vs. 63.2 ± 6.2 mL · kg (- 1) · min (- 1), respectively (p=0.67), effect size (ES)=0.08, and for FLX, at 43 ± 5.9 vs. 41 ± 6.0, respectively (p=0.11, ES=0.34); the YOUNGER tercile exhibited higher values for HRmax than the OLDER tercile, at 194 ± 8.1 vs. 189 ± 8.8 b · min (- 1), (p<0.01, ES=0.59). Players in the OLDER tercile did not present an age-predicted decrease in VO(2max), whereas HRmax and FLX diminished with age as predicted. We conclude that, at least for these variables, younger and older players were effectively identical in their pre-season levels of conditioning.