Performance In Young Soccer Players Research Articles

Assessment of Performance in Youth Soccer Players: Should We Consider the Maturation Status?

The influence of biological maturity status on talent identification and development in youth soccer has been debated extensively. Alternative methods have thus recently emerged to estimate maturity status, such as the Pubertal Development Scale (PDS), but their relationship with physical capabilities of young soccer players still needs to be determined. The present study investigated the relationships of different PDS-derived pubertal status measures, chronological age, and relative age with selected performance variables in youth soccer. Sixty-one male soccer players were assessed for physical capabilities using field tests for sprinting, vertical jumps (countermovement jump, CMJ), intermittent high-intensity endurance, and repeated sprint ability. Chronological age was defined as the number of days since birth, and relative age was defined in terms of age quarters. PDS-derived measures of puberal status, otherwise, were determined as an average PDS score, a PDS category score, and a pubertal category. Chronological age, relative age, and measures of pubertal status were scarcely related (p > 0.05) to selected measures of soccer performance. Significant correlations were only found between different measures of pubertal status and the variable "work" in the CMJ test (range r = 0.33–0.36; p < 0.01) and between chronological age and CMJ height (r = −0.297; p = 0.02). The present results suggest that physical performance of young soccer players is poorly related to chronological age, relative age, and pubertal status. Potential effects of biological maturity status on physical capabilities may not be easily identifiable in a group of young soccer players narrowed in terms of chronological age and training status.

The impact of different game formats on players’ and team performance in youth soccer competitions

The study aimed to investigate the impact of game formats on the running and technical–tactical performance of young soccer players, as well as on players’ dynamics of spatial occupation during competitions. Eleven players of a U-11 team (11.10 ± 0.39 years old) participated in three competitions specifically designed to analyze the impact of different game formats: 5vs5 (F-5), 7vs7 (F-7) and 11vs11 (F-11). Players’ running performance and dynamics of spatial occupation were analyzed using the GPSs devices from WIMU PRO™ devices (10 Hz). Players’ and team's technical–tactical performance was also analyzed using the Team Sports Assessment Procedure (TSAP) and the Offensive Sequence Characterization System (SCSO), respectively. It was observed that the teams tended to adopt a less direct style in the F-11 ( LpW: F7 vs. F-11 p = 0.001 and F-5 vs. F-11 p = 0.002), with a lower rate of spatial exploration (F-7 vs. F-11 p = 0.001 and &&F-5 vs. F-11 p = 0.001) and lower running demand ( Sprint: F-7 vs. F-11 p = 0.001 and F-5 vs. F-11 p = 0.014; HSR: F-7 vs. F-11 p = 0.001 and F-5 vs. F-11 p = .001). In addition, the F-11 allowed the players to have less involvement during the match (F-7 vs. F-11 p = 0.003; F-5 vs. F-11 p = 0.001), as well as a lower technical–tactical performance (F-7 vs. F-11 p = .003 and F-5 vs. F-11 p = .005). Our results highlight the importance of adjusting the game formats used in youth competitive environments to players’ intrinsic dynamics.

The effect of plyometric training program on agility, jumping, and speed performance in young soccer players

Background and Study Aim. The aim of this study was to examine the effect of a 6-week plyometric training program on agility, vertical jump, squat jump, and speed performance in soccer players. Material and Methods. A total of 26 male soccer players actively playing for Ankara Batıkent Kartal Sports Club participated in the study as volunteers. The players had an average age of 15.04 ± 0.16 years, an average height of 172.48 ± 5.14 cm, and an average body weight of 62.65 ± 0.38 kg. Data on the players' gender, age, body weight (kg), height (cm), body mass index (BMI), agility, vertical jump (cm), squat jump, and 30 m speed were obtained. Statistical analysis was performed using SPSS 25 software. The normality of the data was examined using the Shapiro-Wilk test. Paired samples t-test was used to determine within-group differences, and independent samples t-test was used to determine differences between groups. A statistical significance level of p < 0.05 was considered for all evaluations. Results. The plyometric training program was effective in improving agility, vertical jump, squat jump, and speed performance in the experimental group. There was a significant difference in agility and 30 m speed values in the pre-test and post-test evaluations of the Control group, but no difference was observed in vertical jump and squat jump values. Additionally, in the pre-test and post-test comparison between the experimental and control groups, a significant difference was observed in agility, vertical jump, and squat jump values. However, no significant difference was found in 30 m speed values. Conclusions. That plyometric training program is effective in improving agility, vertical jump, squat jump, and 30 m speed values.

Effects of a Low Dose of Orally Administered Creatine Monohydrate on Post-Fatigue Muscle Power in Young Soccer Players.

The use of creatine monohydrate (Cr) in professional soccer is widely documented. However, the effect of low doses of Cr on the physical performance of young soccer players is unknown. This study determined the effect of a low dose of orally administered Cr on muscle power after acute intra-session fatigue in young soccer players. Twenty-eight young soccer players (mean age = 17.1 ± 0.9 years) were randomly assigned to either a Cr (n = 14, 0.3 g·kg-1·day-1 for 14 days) or placebo group (n = 14), using a two-group matched, double-blind, placebo-controlled design. Before and after supplementation, participants performed 21 repetitions of 30 m (fatigue induction), and then, to measure muscle power, they performed four repetitions in half back squat (HBS) at 65% of 1RM. Statistical analysis included a two-factor ANOVA (p ˂ 0.05). Bar velocity at HBS, time: p = 0.0006, ŋp2 = 0.22; group: p = 0.0431, ŋp2 = 0.12, time × group p = 0.0744, ŋp2 = 0.02. Power at HBS, time: p = 0.0006, ŋp2 = 0.12; group: p = 0.16, ŋp2 = 0.06, time × group: p = 0.17, ŋp2 = 0.009. At the end of the study, it was found that, after the induction of acute intra-session fatigue, a low dose of Cr administered orally increases muscle power in young soccer players.

Does Short-Term Speed Endurance Soccer Training Improve Physical Performance?

Objectives. This study is aimed at analyzing the impact of short-term Speed Endurance Soccer Training (SEST) training on the physical performance of young soccer players. Materials and methods. The true experiment method was used in this study. The study population comprised a total of 122 individuals. Furthermore, by using random sampling techniques, a sample of 30 persons was selected with an average age of 15.2 ± 0.81 years, height 168.1 ± 4.82 cm, weight 57.85 ± 11.93 kg, and BMI 20.34 ± 3.37. Physical performance instruments included the Running Based Anaerobic Sprint Test (RAST), Yo-Yo intermittent test level 1, 20-meter sprint, and standing broad jump test. The study used the paired t-test to evaluate the effect of each group and the independent samples t-test to compare the improvement in the experimental (SEST) and control groups. Statistical significance was set at p < 0.05. Results. The paired t-test showed significant differences between the pretest and post-test in the SEST group in anaerobic (p = .000, Δ% = 8.4), aerobic (p = .000, Δ% = 7.48), and speed (p = .000, Δ% = 3.39) capacities. Meanwhile, there were no considerable differences in the variables for the control group. According to the independent t-test results, a significant difference in effect between the SEST group and the CTRL group was revealed. The SEST group demonstrated marked differences in anaerobic, aerobic and speed variables with a p-value = 0.000. Conclusions. The study reveals that short-term Speed Endurance Soccer Training contributes to enhancing the physical performance of soccer players. However, caution should be exercised regarding the potential risk of hamstring injury in individuals with unprepared muscles.

Influence of contextual factors on match running performance of starters and non-starters in elite youth male soccer players.

This study investigated the effects of match location, quality of opposition (classified into: strong [1st to 4th position]; intermediate [5th to 15th position]; weak [16th to 20th position]), and match outcome on the match running performance of starters and non-starters from a top elite Brazilian soccer team. Absolute measures were calculated using total distance, high-speed (19.8-25.2 km·h-1), sprinting (≥ 25.2 km·h-1), total distance high-acceleration (> 2m·s2), and deceleration (< -2m·s2) were recorded by GPS units from a sample of young soccer players (N = 25) in a total of 17 matches. Relative measures were calculated by dividing absolute measures by the total duration of the matches. Non-starters covered greater total distance (p = 0.02), sprinting (p = 0.02), high-acceleration and deceleration (p = 0.04), sprinting distance relative per minute played (p = 0.005), and high-acceleration and deceleration relative per minute played (p < 0.001) when the team plays at home, strong opponents, and wins the matches. Starters covered greater total distance in high-speed running (p = 0.04), high-acceleration and deceleration (p = 0.03), and high-speed running relative per minute played (p = 0.04) when the team plays strong opponents and wins the matches. These findings highlight the impact of contextual factors during matches on the locomotor performance of young soccer players.

The effects of proprioceptive exercise training on physical fitness and performance of soccer skills in young soccer players.

The purpose of this study is to analyze the effect of proprioceptive exercise training on soccer skills and physical fitness in young soccer players. Nineteen young soccer players participated in the study. Participants were divided into proprioceptive exercises training (PT) and control (Cont) groups. The physical fitness and soccer skill performance test assessed at pre- and posttraining. Balance ability and power significantly improved in both groups after 8 weeks of training (P<0.05). Dribble in the PT group was similar between pre- and posttraining, with a statistically significant difference in the Cont group (P<0.05). There were no significant differences within and between groups according to training in the left and right feet for juggling. The PT and Cont groups did not differ significantly regarding short passes posttraining. However, a significant improvement in long passes was observed in the PT group after training period (P<0.05). Shooting was no different between and within the groups. In conclusion, these inconsistent findings are thought to be due to the applied exercise method, training duration, and the specificity of the physical growth period of the young players. Therefore, it is necessary to increase the frequency and time of proprioceptive exercise training and apply factors for cognitive ability improvement to training programs for young soccer players in future studies. These studies could suggest appropriate training methods necessary to improve the performance of young soccer players.

Comparison of 10% vs. 30% Velocity Loss during Squat Training with Low Loads on Strength and Sport-Specific Performance in Young Soccer Players.

The aim of this study was to compare the effects of two velocity-based resistance training (RT) programs using moderate loads (45-60% 1RM) but different magnitudes of velocity loss (VL) limits (10% vs. 30%) on the changes in physical performance in young soccer players. Twenty young soccer players were randomly allocated into two groups: VL10% (n = 10) and VL30% (n = 10). All participants were assessed before and after the 8-week RT program (twice a week) involving the following tests: 20 m running sprint (T20), countermovement jump (CMJ), kicking a ball (KB), and progressive loading test in the full squat (SQ) exercise. The RT program was conducted using only the SQ exercise and movement velocity was monitored in all repetitions. Significant 'time × group' interaction (p < 0.05) was observed for sprint performance, KB and 1RM in the SQ exercise in favor of VL10%. No significant changes between groups at post-test were observed. The VL10% resulted in significant (p < 0.05-0.001) intra-group changes in all variables analyzed, except for KB, whereas VL30% only showed significant (p < 0.05) performance increments in a sprint test and 1RM in the SQ exercise. The percentage of change and the intra-group's effect size were of greater magnitude for VL10% in all variables analyzed compared to VL30%. In conclusion, our results suggest that, for non-trained young soccer players, squat training with low to moderate relative loads and 10%VL is sufficient to elicit significant increases in muscle strength and sport-specific actions compared to 30%VL in the set.

Effectiveness of short vs. long-distance sprint training on sprinting and agility performance in young soccer players.

The purpose of this study was to examine the effects of short sprint-distance training (SST) compared with long sprint-distance training (LST), matched for the total session training volume, on short-, medium- and long-distance sprint performance and agility in young soccer players. Eighteen U19 male players (age: 17.1 ± 0.7 years; height: 178.0 ± 6.3 cm, body mass: 69.4 ± 6.6 kg) were randomly assigned to SST (n = 9) or LST (n = 9) group. The intervention programs were performed 2 times a week over 6 weeks. Before and after training period, 5 m, 10 m, 20 m, 30 m and 40 m sprint, and agility were assessed. Within-group analysis showed significant improvements (p ≤ 0.001) in 5 m, 10 m, 20 m, 30 m and 40 m sprint from pretest to posttest in SST (9.2%, 6.6%, 5.3%, 2.9%, and 2.5%, respectively) and LST (10.5%, 8.5%, 6.5%, 5.1%, and 4.7%, respectively). Players in both SST and LST also showed significant enhancements in agility from pretest to posttest. In the between-groups analysis, there were no differences between the sprint training groups (SST vs. LST) in any variable (p > 0.05). In conclusion, the findings of this study indicate that both sprint training distances used seem to be effective to improve soccer-specific performance measures. However, due to the better percentage changes obtained by LST group in all fitness variables, this method could be considered as preferred method.

Mixed Training Programs Applied to Young Soccer Players: Effects on Speed-Power Abilities.

We compared the effects of two 4-week strength-power-speed training protocols on physical performance of young soccer players. Twenty-three highly trained under-20 soccer players were randomly allocated to two mixed-training groups: 1) "traditional" (TRAD: n=11), comprising vertically oriented strength-power exercises and linear sprints; or 2) "multidirectional" (MULTI: n=12), combining vertically and horizontally oriented strength-power exercises, linear sprints, and change-of-direction (COD) drills. Squat jump (SJ) and countermovement jump, 2) linear sprint, COD speed, and 3) jump-squat (JS) and hip-thrust (HT) power tests were performed pre- and post-training. Differences were determined using a two-way ANOVA with repeated measures and "target scores" were used to detect real changes in performance. No group-time interactions were found for any of the variables (p>0.05). Significant increases (p<0.05) in 20-m sprint velocity, JS- and HT-power were found in both groups, and in SJ in TRAD. Individual analyses revealed a greater number of meaningful changes in zig-zag velocity in MULTI while most players in TRAD displayed meaningful increases in SJ height. In conclusion, both training protocols resulted in similar adaptations but, at the individual level, it appears that MULTI protocol is superior to improve COD ability while TRAD should be preferred to maximize vertical jumping capabilities during short soccer pre-seasons.

An Investigation of the Relationship Between Horizontal and Vertical Jumping vs Speed Performance in U-12 Soccer Players

This study examined the relationship between horizontal and vertical jumps and speed performance in U-12 soccer players. Twenty-six amateur soccer players from a soccer club participated in the study. Speed tests (0-5m/0-10m/0-20m and 0-30m), horizontal jump tests, and vertical jump tests were applied. In the literature review, studies examining the relationship between speed performance with vertical and horizontal jump performance in young soccer players were observed, but, to our knowledge, no study has been found that evaluates horizontal jump as a standing long jump with hands on hips in young soccer players. The relationship between variables was measured by Spearman correlation, with a significance level of α set at 0.05.The mean values of the measured parameters of the U-12 soccer players who participated in the study were; age 10.88 ± 0.81 years, height 142.92 ± 4.65 cm, body weight 35 ± 3.44 kg, 5m speed time 2.36 ± 0.13 sec, 10m speed time 3.45 ± 0.16 sec, 20m speed time 5.40 ± 0.35 sec, 30m speed time 7.19 ± 0.45 sec, horizontal jump (SLJHH) value 140.42 ± 12.85 cm, horizontal jump (SLJHF) value 163.84 ± 13.79 cm, vertical jump (VJ) value 26.57 ± 4.33 cm. The study findings indicated significant relationships between 5m and SLJHF/VJ, 10m and SLJHF/SLJHW, and 20m and 30m with SLJHF/SLJHH/VJ (p &lt; 0.05), while no significant relationship between 5m and SLJHF, and 10m and VJ (p &gt; 0.05). In conclusion, a negative relationship was found between horizontal and vertical jump and speed performance in U-12 soccer players. Therefore, when evaluating speed performance in this age group, horizontal and vertical jump performance should also be taken into consideration. Developing lower extremity strength should be prioritized in training programs tailored to this age group, aiming to improve speed performance.

The Effect of Environmental Disasters on Endocrine Status, Hematology Parameters, Body Composition, and Physical Performance in Young Soccer Players: A Case Study of the Aral Sea Region.

The Aral Sea region (Uzbekistan) is infamous because of the ecological disaster characterized by the disappearance of the Aral Sea due to excessive uncontrolled water intake for agriculture needs. A new desert occurrence, soil and climate aridization led to pesticide and toxic metals environment pollution. The impact of environmental conditions in some areas of Uzbekistan on the health of soccer players is not as noticeable as, for example, the effectiveness of training, so it is not widely discussed in scientific papers. The aim of the present study was to study the features of endocrine status, hematology parameters (e.g., red blood cells (RBC) and hemoglobin (Hb)), and their influence on body composition and physical fitness performance in local young soccer players of the Aral Sea region as the territory of ecological disaster. The study involved 60 male soccer players aged from 18 to 22 years. Participants were divided into two groups: the experimental group (EG), which consisted of 30 soccer players living on the territory of the Aral ecological disaster region, and the control group (CG), which included 30 soccer players, natives of the ecologically favorable region of Uzbekistan. All volunteers had anthropometric measurements, concentrations of insulin-like growth factor-1 (IGF-1), total testosterone (TT), estradiol (E2), cortisol (C), RBC, and Hb count. Moreover, Yo-Yo Intermittent Recovery Test Level 1 (YYIRT1) and professional skills tests such as dribbling shuttle test (DSt) and goal accuracy test (GAt) were assessed. When comparing the CG group to the EG group, it was observed that the EG group exhibited statistically significantly reduced levels of TT and E2 (p < 0.05). No significant statistical difference was observed between the two groups in terms of IGF-1 and C (p > 0.05). Regarding hematological parameters, Hb, Ht, and mean corpuscular volume (MCV) were found to be significantly lower in the EG compared with the CG (p < 0.05). Moreover, the distance covered in the YYIR1 test was found to be significantly lower in soccer players within the EG compared with the CG (p < 0.05). Additionally, it was determined that there was no significant difference between the groups in terms of DSt and GAt values (p > 0.05). Lastly, significant differences were observed between the EG and CG in terms of anthropometric characteristics (diameters, skinfold, and somatotype profile) (p < 0.05). The present study showed that the changes in evaluated characteristics might result from the complex influence of endocrine-disrupting chemicals, the content of which is high in the environment of the Aral Sea region. The results obtained may help monitor the health of athletes living in an environmentally unfriendly environment.

Sleep and chronotype influence aerobic performance in young soccer players.

People can be classified into three chronotypes (CT): morning-type (M-type), Neither-type (N-type) and Evening-type (E-type). M-types perform better in the morning, E-types in the evening. It seems that bad sleep worsens physical performance. The impact of sleep and CT on specific sports and populations is unclear. Therefore, we wanted to assess agility, strength and endurance in young soccer players in relation to their sleep and chronotype. 58 players (13-19years) were recruited. Sleep and CT were assessed by questionnaires. The physical trial was performed at 8:30 a.m. and 6:00 p.m., and included three tests to determine agility, strength and endurance. The sample was classified by CT as M-types (n = 11), N-types (n = 29) and E-types (n = 18). Furthermore, they were categorized as people with Good Sleep/Wake quality (GSW, n = 28) and people with Bad Sleep/Wake quality (BSW, n = 30). Comparing the three CTs in the aerobic test, M-types performed better in the morning (p = 0.01), while E-types in the evening (p < 0.001). GSW performed better than BSW (p = 0.019) in the aerobic test in the p.m. session. These results underline the difference in aerobic power between M-and E-types during the morning and evening session; moreover, they show a difference in p.m. aerobic performance according to sleep quality.

Effects of Concurrent High-Intensity and Strength Training on Muscle Power and Aerobic Performance in Young Soccer Players during the Pre-Season.

The aim of the present study was to evaluate two different intervention programs applied during a 4-week pre-season period. Twenty-nine players participated in this study and were divided into two groups. One group (BallTrain, n = 12, age: 17.8 ± 0.4 years, body mass: 73.9 ± 7.6 kg, height: 178 ± 0.1 cm, body fat: 9.6 ± 5.3%) performed a higher percentage of aerobic training with ball and strength training using plyometrics and exercises with body weight. The other group (HIITTrain, n = 17, age: 17.8 ± 0.7 years, body mass: 73.3 ± 5.0 kg, height: 179 ± 0.1 cm, body fat: 8.0 ± 2.3%) trained with high-intensity interval training (HIIT) without the ball and performed resistance training with weights in the same session. Both groups trained for strength (two times/week) and performed aerobic-anaerobic fitness without the ball, passing games, and tactical and small-sided games. Lower limb power (CMJ) and aerobic fitness (Yo-Yo intermittent recovery test level 1-IR1) were evaluated before and after the four-week training program. Yo-Yo IR1 performance was improved in both groups, but the improvement was greater for the HIITTrain than BallTrain group (468 ± 180 vs. 183 ± 177 m, p = 0.07). CMJ showed a non-significant improvement in the BallTrain group (5.8 ± 8.8%, p = 0.16), but it decreased by 8.1 ± 9% (p = 0.001), in the HIITTrain group. In conclusion, we have shown that a short pre-season period of training results in improvements in aerobic fitness in both groups, with high-intensity interval training showing superior adaptations than training with the ball. However, CMJ performance was reduced in this group, possibly suggesting higher fatigue levels and overload, and/or showing the effects of concurrent HIITTrain and strength training in soccer.

Effects of a Short Half-Time Re-Warm-Up Program on Matches Running Performance and Fitness Test Performance of Male Elite Youth Soccer Players

The aim of the study was to investigate the effect of a half-time short re-warm-up (RW) strategy on the performance of young soccer players in tests of physical abilities and running performance during matches. Twenty-three players (under 17) participated in the study. Body temperature, 10 m sprint, 30 m sprint, the Illinois agility test, countermovement jump (CMJ), and squat jump (SJ) were measured, immediately post-warm-up. Then in one condition, the tests were repeated after a passive rest, and in the other condition, after a 12 min passive rest and 3 min RW. Furthermore, the RW was applied at half-time of two of the four matches where the running performance was measured in the first quarter of the two halves. The results showed that the two conditions differed significantly in the 10 m sprint and CMJ performances (p &lt; 0.001 and p = 0.049, respectively). After the passive rest, a significant decrease in body temperature and performance in SJ was observed (p &lt; 0.001 for both). No other differences were observed. In conclusion, the short RW program can limit the decrement in performance in power tests such as sprints and jumps.

Sprint and Jump Training on Sand vs. Grass Surfaces: Effects on the Physical Performance of Young Soccer Players.

Pereira, LA, Freitas, TT, Zabaloy, S, Ferreira, RCA, Silva, ML, Azevedo, PHSM, and Loturco, I. Sprint and jump training on sand versus grass surfaces: effects on the physical performance of young soccer players. J Strength Cond Res 37(9): 1828-1833, 2023-The aims of this study were to (a) examine the effects of a 6-week sand training program including both sprint and jump exercises on the speed-related and vertical jump performance of elite young soccer players and (b) compare the changes induced by a sand training scheme with those induced by a similar training program (in volume, intensity, and exercise types) performed on grass. Twenty-four under-20 soccer players were randomly allocated to 2 training groups, as follows: "sand" ( n = 12) or "grass" ( n = 12) groups. Athletes performed squat and countermovement jumps, linear sprints, and Zigzag change-of-direction speed tests at pre-, mid- (after 6 training sessions), and postintervention (after 12 training sessions). Both groups exhibited similar increases in the vertical jump and Zigzag performance after the 6-week training period ( p values ranging from 0.0001 to 0.025; effect size ranging from 1.05 to 3.78, for main effect of time). No significant changes were detected for the linear sprint velocity for both the groups ( p values ranging from 0.079 to 1.00; effect size ranging from 0.07 to 0.65, for main effect of time). In summary, training on sand or grass surfaces resulted in similar improvements in the physical performance of elite young soccer players. This study confirms the current evidence on the effectiveness of both soft and harder training surfaces in improving the sprint and jump performance of team-sport athletes.

Body size, maturation and motor performance in young soccer players: relationship to technical actions in small-sided games

The objective of this study was to investigate the relative contributions of body size, skeletal age, and motor performance variables with technical actions through an ecological model during small-sided soccer games, and the interaction of biological maturation with technical and motor performance in young players. In this cross-sectional study, eighty-two young players (14.4 ± 1.1 years), belonging to state-level soccer teams and divided by category (U-13 and U-15), were included. Players having an injury in the evaluation period were not included in the study. Measurements of body size, skeletal age (SA), motor tests, and technical actions in small-sided games (SSG) were performed (3 × 3 plus goalkeeper) in two periods (halves) of four minutes. Differences between age groups were found for SA (ES = -2.36), chronological age (ES = -3.89), body mass (ES = -2.09), height (ES = -1.90), and fat-free mass (ES = -2.09). Positive associations were found between body size (R = 0.43 to R = 0.48) and manipulation (R = 0.50 to R = 0.52) indicators and numbers of technical actions (CB and SS), except for stature with LB (R = -0.42) in the U-13 age group. In the U-15 category, skeletal age (R = -0.29 to R = -0.30) and body mass (R = -0.28 to R = -0.29) were negatively associated with the number of technical actions (RB, NB, LB, and OB) (P > 0.05) and positively with the balance with LB (R = 0.26). In conclusion, body size, SA, and motor performance influenced technical actions in SSG differentially in each category. U-13 heavier players and those with a better motor performance presented higher involvement due to the higher.

INFLUÊNCIA DO TREINAMENTO COM PESOS SOBRE A FORÇA DE MEMBROS INFERIORES EM JOGADORES DE FUTEBOL

ABSTRACT Introduction Soccer games are of long duration and more confrontational; in the second half of the game, many players have a decline in their physical level, leading to loss of matches. Objective To explore the effect of weight training on lower limb fitness in soccer players. Methods 60 athletes were included as subjects and randomly divided into control group, weight training group, and traditional physical fitness training group. All athletes trained for 45 minutes 3 times a week for 6 weeks. Before and after training, lower limb strength and proprioception were evaluated, and the strength of the knee flexor and extensor group was assessed by isokinetic muscle tester. Results Both weight training and traditional physical training were able to improve the vertical jump performance of young soccer players, the training effects of both groups were equivalent. Conclusion Weight training has the same enhancing effect as traditional physical training in terms of strength and explosive power, promoting athletic performance in youth soccer players. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

Daytime fluctuations of endurance performance in young soccer players: a randomized cross-over trial

ObjectivesFluctuations of physical performance and biological responses during a repetitive daily 24-h cycle are known as circadian rhythms. These circadian rhythms can influence the optimal time of day for endurance performance and related parameters which can be crucial in a variety of sports disciplines. The current study aimed to evaluate the daytime variations in endurance running performance in a 3.000-m field run and endurance running performance, blood lactate levels, and heart rate in an incremental treadmill test in adolescent soccer players.ResultsIn this study, 15 adolescent male soccer players (age: 18.0 ± 0.6 years) performed a 3.000-m run and an incremental treadmill test at 7:00–8:00 a.m. and 7:00–8:00 p.m. in a randomized cross-over manner. No significant variations after a Bonferroni correction were evident in endurance running performance, perceived exertion, blood lactate levels, and heart rates between the morning and the evening. Here, the largest effect size was observed for maximal blood lactate concentration (9.15 ± 2.18 mmol/l vs. 10.64 ± 2.30 mmol/l, p = .110, ES = 0.67). Therefore, endurance running performance and physiological responses during a field-based 3.000-m run and a laboratory-based test in young male soccer players indicated no evidence for daytime variations.

Effects of Age and Playing Tactics on the Individual Tactical Behavior in U10 and U12 Elite Spanish Soccer Players.

The aim of this paper was to explore the effects of age and playing tactics on the individual tactical behavior and performance in young soccer players. A total of 1247 individual possessions during 16 knockout matches from LaLiga Promises U12 tournament (n = 621) and LaLiga U10 Iscar Cup (n = 626) were analyzed by observational methodology. Multilevel and multivariate logistic regression models were created to explain the interdependent effects of age category and playing tactics on the individual tactical behavior and performance. Youth players performed most of their actions against defensive pressure (72.5%), during offensive support (91.3%) and receiving the ball facing forward (62.6%). The most frequent action was to receive and pass the ball (69.6%) and the level of offensive success was 56.9%. The multilevel mixed models revealed that U10 players presented higher odds of running with the ball vs. passing the ball (OR = 1.823; 95% CI: 1.333-2.493; p &lt; 0.001) and lower odds of achieving offensive success (OR = 0.698; 95% CI: 0.525-0.928; p &lt; 0.05) than U12 players. Regarding playing tactics, technical-tactical dimensions such as the players' body shape when receiving the ball, offensive support, defensive pressure, collective type of attack and type of technical action presented a significant and combined effect on the offensive success regardless of age category, playing position and match status. This study found tactical differences between U10 and U12 age categories and revealed important interactive effects of multiple tactical dimensions on the individual offensive behavior and performance in youth soccer players.