The influence of maturation, fitness, and hormonal indices on minutes played in elite youth soccer players: a cross-sectional study

Exploring the Relationship of Declarative Tactical Knowledge With Participation, Football Competence, and Potentiality in a Professional Club (Real Sociedad)

We compared the declarative tactical knowledge (DTK) of 196 male and female players (16.9 ± 2.4 years) belonging to the academy of a Spanish professional football club with their participation (minutes played), football competence (coaching staff assessment), and future potential (technical direction prediction). The DTK had no correlation with the minutes played (%) by the participants during the 2021-22 season (r = -.162, p = .045). Student's t test for independent samples compared the football competence of the participants with high DTK (n = 74) and low DTK (n = 76), proving a small impact (p = .021, d = 0.39) in favor of the first group. Although the high-DTK group showed a better average of potentiality, the technical direction identified more potential players for the first team in the low-DTK group. In conclusion, no solid evidence was found to justify that participants with higher DTK in each team were those who played more minutes and showed greater football competence and potentiality.

The Influence of Subjective Perceptions and the Efficacy of Objective Evaluation in Soccer School Players' Classification: A Cross-Sectional Study

OBJECTIVES

The first objective was to investigate the influence of subjective perceptions and the efficacy of objective evaluation regarding the classification of soccer school players by their level of performance. The second objective was to advise on accurate collocation according to objective assessment of players' performance.

METHODS

An objective evaluation of the players' motor performance abilities and coaches' subjective perceptions of the players' levels of performance was conducted with 34 young football players (U11) from Torino FC soccer school. The players were allocated to three groups based on their perceived performance level at the start of the season. The players were evaluated using a field test battery, and team coaches provided subjective ratings of the players' abilities.

RESULTS

MANOVA showed significant differences between the playing levels (F = 2.185, p < 0.05; partial η2 = 0.34) in the 10 × 5 shuttle run, 20 m sprint test (objective evaluations), heading, understanding of the game, positioning on the field, speed and agility (subjective perception) (F = 1.951, p < 0.05; partial η2 = 0.43). A discriminant analysis of the field test scores revealed that 76.5% of players were correctly categorised in one of the three performance-level groups. However, the first group (the best players) had the lowest predictive accuracy rate (58.3%). By comparison, the second group (the average players) had a much higher predictive accuracy rate (83.3%), and the third (the weakest players) had the highest (90.0%).

CONCLUSIONS

These findings support the role of objective performance evaluation in categorising players of different skill in soccer schools.

Effects of 8-Week In-Season Contrast Strength Training Program on Measures of Athletic Performance and Lower-Limb Asymmetry in Male Youth Volleyball Players

Strength training using high and lower load such as contrast training (CST) seems to be beneficial as it addresses larger adaptive reserves in youth athletes. Therefore, the aim of this study was to investigate the effects of CST on dynamic balance (composite score during dynamic balance test (CS-YBT)), one repetition maximum lower-limb back squat (1RM), jumping performance (single-leg hop (SLH) or countermovement jump height (CMJ)), lower-limb asymmetry (predicted from the single-leg jump performance between two legs [ILA]) in elite youth male volleyball players. Thirty-one male youth volleyball players aged 14 years were randomly assigned to a CST group (n = 16) or a control group (n = 15). The tests were performed before and after 8 weeks of training. Significant group × time interactions was observed for CS-YBT [p < 0.001, ηp2 = 0.70], 1RM [p < 0.001, ηp2 = 0.95], SLH with right and left leg [p < 0.001, ηp2 = 0.69 and 0.51], CMJ [p < 0.001, ηp2 = 0.47]), whilst it was not notable in ILA [p < 0.294]. Post hoc tests showed that CST group demonstrated greater improvement in all of the dependent variables from medium to large effect size (for all p < 0.001). As a result, 8 weeks of CST twice a week can be an effective and efficient training along with volleyball training to improve skill-related fitness measures, except for lower-limb asymmetry in young volleyball players.