The aim of this study was to assess the effects of plyometric training with an agility ladder on components of physical fitness in youth soccer players. A total of twenty male under-13 soccer players were randomly assigned to a plyometric training group with an agility ladder (n=10) or a control group (n=10). Before and after training intervention linear sprint test (5 m, 10 m, 20 m), vertical jump ability (squat jump, countermovement jump and countermovement jump with arms), agility test, and slalom dribble test were assessed. The plyometric training with agility ladder was applied two times per week over six weeks. Data were analyzed using linear mixed model. The plyometric training group showed significant improvements (p0.05). The between-group analysis showed significant differences in countermovement jump with arms (p=0.03), but no significant differences (p>0.05) were found in squat jump, countermovement jump, sprint, agility test, and slalom dribble test. In conclusion, the short-term plyometric training with agility ladder seems to be ineffective and not time-efficient to improve physical fitness in youth soccer players. However, the interpretation of these results must be understood within the sample size limitations.

Current soccer scientific literature is scarce with regard to examining the technical performance of substitute players. Purpose: This study aimed to analyze the physical and technical performance of substitute players versus those who completed the entire match or were replaced and also examine the performance of substitutes across different playing positions. Method: The sample was composed of 6,631 match observations from 431 professional soccer players competing in the German Bundesliga during the season 2018–2019. These observations were divided into three groups: entire match (n = 3,807), replaced (n = 1,412), and substitutes (n = 1,412). Linear mixed models were adjusted to compare the performance of the three groups independently of playing position and separately for each position (central defenders, fullbacks, central midfielders, wide midfielders, and attackers). Results: Substitute players showed higher total distance covered (effect sizes [ES]: 0.99–1.06), number of sprints (ES: 0.60–0.64), and number of fast runs (ES: 0.83–0.91) relative to playing time than replaced and entire match players. The differences in technical performance between groups varied according to playing position. Substitute central defenders showed less possession (ES: 0.39–0.41), touches (ES: 0.47–0.57), and passes (ES: 0.54–0.59) but higher defensive performance (ES: 0.51–0.54) than replaced and entire match players. Substitutes in midfield and attack positions displayed more possession (ES: 0.22–0.47), touches (ES: 0.27–0.37), and shots (ES: 0.22–0.28) than replaced and entire match players. Conclusion: This study has shown that substitutes are able to improve the performance of the players who completed the entire match or were replaced in both physical and some technical variables depending on playing position.

The aim of this study was to examine the association between the time spent in possession by teams and the match running performance in elite soccer matches. Match performance data were collected from players in Spanish LaLiga (8,468 individual match observations of 412 outfield players) using a multiple-camera computerised tracking system. A k-means cluster analyses classified teams depending on time spent in possession of the ball: Very High-Percentage Ball Possession Teams (VHPBPT), High-Percentage Ball Possession Teams (HPBPT), Low-Percentage Ball Possession Teams (LPBPT) and Very Low-Percentage Ball Possession Teams (VLPBPT). Overall, physical indicators were highly associated with ball possession. Distances covered in VHPBPT were lower than HPBPT, LPBPT and VLPBPT, especially at low and medium speed. Position-specific changes were also evident for physical profiles. Attackers (Central midfielders, External midfielders and Forwards) in VHPBPT covered fewer meters per minute at any speed than their counterparts in HPBPT, LPBPT or VLPBPT. However, defenders (Central defenders and External defenders) in VLPBPT covered lower distances. These findings may have a great deal of practical implications and may help coaches to better understand match running variations according to ball possession strategies and could be used to develop a model for predicting the physical activity profile in competition.

Player substitutions are one of the main options for the coach to change tactical behavior of his team. Purpose: The present study therefore investigates the effect of player substitutions on tactical behavior in high-performance soccer using positional data. Method: The sample consisted of 659 substitutions from 234 matches played in the German Bundesliga during the season 2016–2017. Substitutions were classified either as neutral (n = 485), defensive (n = 45), or offensive (n = 129) according to the player’s roles. The teams’ tactical behavior before and after each substitution was analyzed using team centroid, inter-team centroid distance, team length and width, length per width (LpW) ratio, stretch index, and space control for the whole pitch and for each third as the dependent variables. Results: The linear mixed model analysis showed different effects for neutral, defensive, and offensive substitutions. Teams displayed significantly lower stretch index after defensive substitutions. LpW ratio increased with neutral and offensive substitutions, while inter-team distance decreased. The position of the team centroid, space control in the middle third and in the attacking third were also greater following an offensive substitution. Conclusions: These findings demonstrate that player substitutions effectively change tactical behavior of teams. Soccer coaches should perform more offensive substitutions to elicit a higher defensive pressure and improve goal-scoring opportunities, especially due to greater space control in the attacking third. In contrast, defensive substitutions can be used to increase defensive effectiveness through increases in team compactness.

This study aimed to examine the effects of age on match-related physical and technical-tactical performance in elite soccer players using a longitudinal design. Data were collected from 154 players who competed in the Spanish first division (LaLiga) between the 2012-13 and 2019-20 seasons. A total of 14,092 individual match observations were analyzed using a computerized tracking system (TRACAB, Chyronhego, New York, NY). The players were classified into five positional roles: central defenders (n = 37); external defenders (n = 44); central midfielders (n = 34); external midfielders (n = 22); and forwards (n = 17). The main results showed that (a) soccer players decreased by an average of 0.56% their total distance covered for each year that they got older. Similarly, the number of high-intensity efforts and distance covered at high-intensity running decreased by 1.80% and 1.42% per year, respectively; (b) players significantly increased their pass accuracy by an average of 0.25% each year that they got older; (c) the detrimental effect of age on total distance and high-intensity running was greater for external defenders, external midfielders, and forwards; and (d) the positive effect of age on pass accuracy was greater for central defenders and central midfielders. Elite soccer players with long-term careers were unable to maintain their match-related physical performance as they got older. However, players can annually improve their technical-tactical skills with increasing age as a possible compensation mechanism against physical performance declines related to aging.

This study aimed to analyse the effect of age on between-match variability of physical performance in professional soccer players. For this purpose, observations on entire match performance were collected on 787 professional soccer players competing in the first or second division of Spanish league during the 2017–2018 season. Players were classified into six groups according to their age: G1 (≤22.5 years), G2 (22.6–25.1 years), G3 (25.2–27.5 years), G4 (27.6–30.1 years), G5 (30.2–33.1 years) and G6 (≥33.2 years). Coefficients of variation (CVs) were calculated individually for each player and performance variable: total distance, low- intensity, medium-intensity, high-intensity running (HIR), sprinting, number of HIR, number of sprints, average speed and maximal speed. The main finding of this study was that players under 25.2 years (G1 and G2) showed lower CVs for high-intensity activities (HIR and sprinting) in comparison with players over 33.1 years (G6). These findings provide useful information for soccer coaches, who could put extra attention on physical performance of the oldest players when they have to play an entire match, because their performance is more variable and uncertain in comparison with the youngest.