Influence of contextual factors on most demanding scenarios in under-19 professional soccer players

Peak Kinematic and Mechanical Demands According to Playing Positions in Professional Male Soccer: Composition Analysis and Characteristics of Locomotor Activities

This study examined the most demanding passages (MDP) of composite kinematic and mechanical activities in professional soccer according to positions. Global positioning system data were collected from 39 male soccer players across two seasons. Kinematic and mechanical MDP were identified by composite MDPk (maximal distance covered across moderate- and high-speed running and sprinting thresholds) and MDPm (maximal magnitude of high-intensity acceleration and deceleration efforts) criterion variables across 5 min moving average periods. Linear mixed models assessed the intensity, number of efforts, and duration of specific locomotor activities of each MDP by position. The kinematic MDP showed higher intensity, effort count, and relative duration of MDPk activities than mechanical MDP (p ≤ 0.001; ES: 0.7-1.7). Conversely, MDPm activities had greater magnitude, efforts, and relative duration in mechanical MDP (ES: 1.9-2.0). Similar constituent variable compositions were observed between peak periods. The MDPk comprised ~60 ± 16% moderate-speed running, ~30 ± 11% high-speed running, and ~14 ± 8% sprinting distances; MDPm included ~35 ± 23% and ~65 ± 23% high-intensity accelerations and decelerations. Positional differences revealed central defenders had lower, while full-backs and wide-midfielders had higher, MDP values. Findings from this study highlight the multidimensional characteristics of composite peak kinematic and mechanical periods in professional soccer. The differential contribution of low- and high-intensity locomotor activities during such periods, in terms of magnitude, number of efforts, and duration, should be considered by practitioners. Such insight can inform effective position-specific training prescription as well as bespoke recovery strategies based on the MDP observed during match play.

Higher final speed in 30-15 intermittent fitness tests correlates with soccer's locomotor demands, not heart rate responses in small-sided soccer games

This study aimed to achieve two objectives: firstly, to analyze the relationships between aerobic fitness, as represented by the VIFT, and the heart rate and locomotor responses of youth male soccer players across various teams; and secondly, to compare players with lower and higher VIFT in terms of performance outcomes extracted during small-sided games (SSGs). A total of twenty-six youth male soccer players, aged 16.5 ± 0.32 years, with 3.4 ± 1.1 years of experience, voluntarily participated in the study. These players belonged to two regional-level tier 2 teams (trained/developmental). In the initial week of observation, the 30-15 Intermittent Fitness Test was implemented to measure the final velocity (VIFT) achieved by the players. Subsequently, the 5v5 format of play was conducted twice a week over two consecutive weeks, during which heart rate responses and locomotor demands were measured. The Pearson product-moment correlation test revealed a significant correlation between VIFT and the total distance covered during the 5v5 format (r = 0.471 [95% CI: 0.093; 0.721], p = 0.015). Conversely, small and non-significant correlations were identified between VIFT and mean heart rate (r = 0.280 [95% CI: - 0.126; 0.598]; p = 0.166), VIFT and peak heart rate (r = 0.237 [95% CI: - 0.170; 0.569]; p = 0.243), as well as VIFT and high-speed running (r = 0.254 [95% CI: - 0.153; 0.580]; p = 0.211). Players with higher VIFT demonstrated a significantly greater total distance, with a large effect size (+ 6.64%; p = 0.015; d = 1.033), compared to those with lower VIFT. Our findings suggest that improved performance in VIFT may lead to covering more distance in 5v5 matches. However, the lack of significant associations between VIFT and heart rate levels during SSGs suggests that they are not strongly correlated, possibly because VIFT is more closely linked to locomotor profile. As a practical implication, coaches may consider organizing players during SSGs based on their VIFT if the goal is to standardize locomotor demands.