Elite Male Soccer Players Research Articles

A comparison of match demands using ball-in-play vs. whole match data in elite male youth soccer players

ABSTRACTInstruction: Effective playing time in soccer is typically < 60 min per game and while players may reposition themselves when the ball is out of play, it is likely the physical demand decreases during this period. Therefore, if this period is included in data when quantifying match demands, it may under-report the physical requirements of soccer players. This study investigated an alternative method for quantifying external workload called ball in play (BiP), which analyses the data excluding stoppages, and thus potentially offers a more insightful analysis of match demands.Methods: Whole match demands as typically recorded via GPS, were compared to those based on BiP, and maximum BiP, with the latter representing worst case scenario phases of play. The 25-elite male youth soccer players (age: 17.9 ± 0.6 years; height: 174.8 ± 6.2 cm; body mass: 66.3 ± 8.1 kg) who participated in this study were also categorised in to positional groups (defender, midfielder, and forward) to assess differences in positional demands.Results: While no differences were noted based on position, whole match metrics were significantly lower than mean and maximum BiP metrics (p < 0.05). There was also a significant difference for maximum BiP outputs across different in-play durations, when comparing 30-60 seconds, 60–90 seconds, and > 90 seconds.Conclusion: This data allows practitioners to gain a deeper understanding of the physical demands imposed on players and plan sessions using targets that better represent match demands.

Injury Profile of Elite Male Young Soccer Players in a Spanish Professional Soccer Club: A Prospective Study During 4 Consecutive Seasons.

As the number of injuries in young soccer players increases, an epidemiological study is the first step in improving preventive strategies. To analyze the injury profile of a Spanish professional soccer club's academy during 4 consecutive seasons and to examine the injury incidence across different chronological age groups. Prospective cohort design. Aggregate injury and exposure data collected during 4 consecutive seasons. Three hundred nine elite male young soccer players. Injuries that led to participation time missed from training and match play prospectively reported by medical or coaching staff of the club. A total of 464 time-loss injuries were observed during this study period. The overall injury incidence was 2.93injuries per 1000 hours, with higher incidence during matches than during training (10.16 vs 2.10injuries/1000h; rate ratio [RR] = 0.21; 95% confidence interval [CI], 0.17-0.25; P < .05), with the U14 age group presenting the lowest injury rate (2.39 injuries/1000 h; RR = 1.15-1.57; P < .05). In terms of injury severity, moderate injuries were the most frequent (1.42 injuries/1000h). Muscle injuries were the most common type of injuries (57.7%; 2.75 injuries/1000 h; RR = 1.84-13.4; P < .05), and hamstrings (93/268) were the most affected muscle group (0.58injuries/1000h; RR = 1.58-2.91; P < .05). Injury incidence showed a seasonal variation as indicated by peaks in August and October. In matches, specifically, the match period between 75 and 90 minutes showed the highest injury incidence (10.29 injuries/1000 h; RR = 1.89-6.38; P < .01). The findings of this study suggest that specific preventive strategies must be implemented to try to reduce the injury incidence in Spanish elite young soccer players attending to the characteristics of each age group.

Effect of the FIFA 11+ on Landing Patterns and Baseline Movement Errors in Elite Male Youth Soccer Players

There is no evidence regarding the effect of the FIFA 11+ on landing kinematics in male soccer players, and few studies exist regarding the evaluating progress of interventions based on the initial biomechanical profile. To investigate the effect of the FIFA 11+ program on landing patterns in soccer players classified as at low or high risk for noncontact anterior cruciate ligament injuries. Randomized controlled trial. Field-based functional movement screening performed at the soccer field. A total of 24 elite male youth soccer players participated in this study. The intervention group performed the FIFA 11+ program 3 times per week for 8 weeks, whereas the control group performed their regular warm-up program. Before and after the intervention, all participants were assessed for landing mechanics using the Landing Error Scoring System. Pretraining Landing Error Scoring System scores were used to determine risk groups. The FIFA 11+ group had greater improvement than the control group in terms of improving the landing pattern; there was a significant intergroup difference (F1,20 = 28.86, P < .001, ηp2=.591). Soccer players categorized as being at high risk displayed greater improvement from the FIFA 11+ program than those at low risk (P = .03). However, there was no significant difference in the proportion of risk category following the routine warm-up program (P = 1.000). The present study provides evidence of the usefulness of the FIFA 11+ program for reducing risk factors associated with noncontact anterior cruciate ligament injuries. The authors' results also suggest that soccer players with the higher risk profile would benefit more than those with lower risk profiles and that targeting them may improve the efficacy of the FIFA 11+ program.

Basal Serum Cortisol and Testosterone/Cortisol Ratio Are Related to Rate of Na+ Lost During Exercise in Elite Soccer Players.

During exercise, the human body maintains optimal body temperature through thermoregulatory sweating, which implies the loss of water, sodium (Na+), and other electrolytes. Sweat rate and sweat Na+ concentration show high interindividual variability, even in individuals exercising under similar conditions. Testosterone and cortisol may regulate sweat Na+ loss by modifying the expression/activity of the cystic fibrosis transmembrane conductance regulator. This has not been tested. As a first approximation, the authors aimed to determine whether basal serum concentrations of testosterone or cortisol, or the testosterone/cortisol ratio relate to sweat Na+ loss during exercise. A total of 22 male elite soccer players participated in the study. Testosterone and cortisol were measured in blood samples before exercise (basal). Sweat samples were collected during a training session, and sweat Na+ concentration was determined. The basal serum concentrations of testosterone and cortisol and their ratio were (mean [SD]) 13.6 (3.3)pg/ml, 228.9 (41.4)ng/ml, and 0.06 (0.02), respectively. During exercise, the rate of Na+ loss was related to cortisol (r = .43; p < .05) and to the testosterone/cortisol ratio (r = -.46; p < .01), independently of the sweating rate. The results suggest that cortisol and the testosterone/cortisol ratio may influence Na+ loss during exercise. It is unknown whether this regulation depends on the cystic fibrosis transmembrane conductance regulator.

Low back pain and lumbopelvic muscles in elite female Australian football players: an exploratory study

Introduction: Low back pain is a common problem in male Australian football players which may have negative consequences on performance and is associated with increased odds of lower limb injury. Whilst deficits in trunk and hip muscle function associated with low back pain have been demonstrated in elite male Australian football and soccer players, little is known about this relationship in female Australian football players. This exploratory study aimed to examine the size and function of trunk and hip muscles in elite female AFL players with and without low back pain.

A Comparison of Functional Movement Abilities of Elite Male Soccer and Handball Players

A Comparison of Functional Movement Abilities of Elite Male Soccer and Handball Players

The Effect of a 20-Week Corrective Exercise Program on Functional Movement Patterns in Youth Elite Male Soccer Players.

Poor functional movement patterns negatively affect the ability to perform fundamental movements with precision and efficiency, increasing injury risk in athletes. To examine the effect of a 20-week corrective exercise program during the competitive season on functional movement patterns in youth elite male soccer players. Cohort study. Team facilities. Sixty-five youth elite male soccer players (age: 15.89 [0.53]y; weight: 67.42 [6.78]kg; and stature: 175.20 [6.34]cm). Of the 4 teams, 2 were randomly selected to take part in the corrective program. Thus, the players were placed into 2 groups: corrective exercise program and control group. Corrective exercise program. Functional Movement Screen (FMS) was used to assess the presence of dysfunctional, asymmetrical, and painful movements in the players before and after the intervention period. In addition to considering the FMS total score (FMStotal), we separated the screen into 3 parts: FMSmove, FMSflex, and FMSstab. A repeated-measures analysis of variance was conducted to determine the effectiveness of the training program on FMS scores. The chi-square test was performed to determine whether there were significant changes in the frequencies of asymmetric and dysfunctional movements after 20 weeks. No athlete experienced severe injuries during the intervention period. There was a significant group by time interaction (P < .01) for FMStotal, FMSmove, and FMSstab, in which only the corrective exercise program increased their scores after the intervention period (P < .05). A chi-square analysis showed a significant (P < .05) decrease in asymmetric and dysfunctional movements at the follow-up in corrective exercise program, whereas these changes were not observed in the control group. Youth elite soccer players demonstrate a high prevalence of asymmetric movements during FMS testing, but their functional movement patterns can be improved during the competitive season following a specific corrective exercise program.

Evaluation for the effects of nutritional education on Chinese elite male young soccer players: The application of adjusted dietary balance index (DBI)

ObjectivesTo evaluate the effect of nutrition education on Chinese elite male young soccer players through the knowledge, attitude, behavior (KAP) survey and an adjusted dietary balance index (DBI). Methods30 Chinese elite male young soccer players were randomly divided into two groups: lecture group (N = 15, Age: 16.7 ± 1.8 years, Height: 173.9 ± 9.0 cm; Weight: 62.4 ± 13.0 kg; Training years: 5.6 ± 2.7 years) and non-lecture group (N = 15, Age: 16.8 ± 1.7 years, Height: 175.5 ± 7.9 cm; Weight: 62.5 ± 12.3 kg; Training years: 6.2 ± 3.3). The comics book was given to the non-lecture group, while the a four-week nutritional quality education along with comic books were given to the lecture group. Before and after 4 weeks nutritional education, dietary nutritional status of both groups was assessed. The main outcome measurements included the scores for each part of the KAP survey, diet status (food-weighing method) and the dietary index in the adjusted DBI-07 system (DBI-low bound score, LBS; DBI-high bound score, HBS; and DBI-diet quality distance, DQD). ResultsIn the lecture group, significant differences were found in the scores of general nutrition knowledge, sports nutrition knowledge and total scores of KAP dietary questionnaire after 4 weeks nutritional education (P < 0.01). However, there is no significant difference in dietary attitude and dietary behavior (P > 0.05) on both two groups. There is no significant change in the DBI-low bound score (LBS), DBI-high bound score (HBS) and DBI-diet quality distance (DQD) of dietary quality index (P > 0.05) in both two groups. ConclusionsFour weeks nutritional quality education improved the understanding of dietary nutrition among Chinese elite male young soccer players.

Age-Matched Z-Scores for Longitudinal Monitoring of Center of Pressure Speed in Single-Leg Stance Performance in Elite Male Youth Soccer Players.

Huurnink, A, Fransz, DP, de Boode, VA, Kingma, I, and van Dieën, JH. Age-matched z-scores for longitudinal monitoring of center of pressure speed in single-leg stance performance in elite male youth soccer players. J Strength Cond Res 34(2): 495-505, 2020-Coordination of corrective motor actions is considered important for soccer performance and injury prevention. A single-leg stance (SLS) test assesses the integrity and proficiency of the sensorimotor control system, quantified by center of pressure averaged speed (COPspeed). We aimed to provide age-matched z-scores for COPspeed in elite male youth soccer players. Second, we assessed a threshold for abnormal long-term change in performance, i.e., critical difference (CD). In a youth academy program, 133 soccer players of 9-18 years were tested twice for both legs (2 repetitions), and one repetition follow-up was conducted at 5.8 months (SD 2.7). Linear regression between age and COPspeed was performed to provide age-matched z-scores. Variance of differences in z-scores at baseline and between sessions was used to estimate the CD up to 5 repetitions. Intraclass correlation coefficients (ICCs) were assessed within and between sessions. The age significantly affected COPspeed (p < 0.0001), with lower values in older players (95% confidence interval; 3.45-9.17 to 2.88-5.13 cm·s, for 9 and 18 years, respectively). The z-score CD ranged from 1.72 (one repetition) to 1.34 (5 repetitions). The ICC of z-scores was 0.88 within session and 0.81 between sessions. In conclusion, the SLS performance in elite male youth soccer players improves with age. We determined age-matched z-scores of COPspeed, which reliably determined performance according to age. The CD allows for detection of abnormal variations in COPspeed to identify players with a (temporary) deterioration of sensorimotor function. This could be applied to concussion management, or to detect underlying physical impairments.

The effects of detraining and retraining periods on fat-mass and fat-free mass in elite male soccer players.

The aim of the study was to examine the effects of a detraining period (DTP) (i.e., off-season) with an individually prescribed training program, and a retraining period (RTP) (i.e., pre-season) combining soccer and flywheel-based strength training on fat-free mass (FFM) and fat-mass (FM) in 10 elite professional male soccer players. The present study used a controlled repeated-measures research design to investigate the changes in FFM and FM using dual-energy X-ray absorptiometry. Whole body %FM increased (effect size (ES) = 0.87 ± 0.46) and FFM reduced after DTP (ES = −0.30 ± 0.19), returning to values comparable to the end of the previous season after RTP. At regional levels, arms, legs, and trunk %FM increased (ES = from 0.42 to 1.29) while trunk-FFM was reduced (ES = −0.40 ± 0.26) after DTP, returning to the values observed at the end of the previous season after RTP. Legs-FFM did not change after DTP, with a substantial increase after RTP in comparison with pre-season values (ES = 0.34 ± 0.29 and 0.53 ± 0.36 for the right and left leg, respectively). Despite the small sample size of the present study, the findings indicate that elite soccer players can be allowed 2 weeks of rest during a five-week DTP, since the changes in %FM and FFM were relatively small, and FM and FFM returned to the optimal initial values for competition after the proposed RTP during the pre-season.

Effects of Neuromuscular Training on Agility Performance in Elite Soccer Players.

BackgroundAgility in general and change-of-direction speed (CoD) in particular represent important performance determinants in elite soccer.ObjectivesThe objectives of this study were to determine the effects of a 6-week neuromuscular training program on agility performance, and to determine differences in movement times between the slower and faster turning directions in elite soccer players.Materials and MethodsTwenty male elite soccer players from the Stade Rennais Football Club (Ligue 1, France) participated in this study. The players were randomly assigned to a neuromuscular training group (NTG, n = 10) or an active control (CG, n = 10) according to their playing position. NTG participated in a 6-week, twice per week neuromuscular training program that included CoD, plyometric and dynamic stability exercises. Neuromuscular training replaced the regular warm-up program. Each training session lasted 30 min. CG continued their regular training program. Training volume was similar between groups. Before and after the intervention, the two groups performed a reactive agility test that included 180° left and right body rotations followed by a 5-m linear sprint. The weak side was defined as the left/right turning direction that produced slower overall movement times (MT). Reaction time (RT) was assessed and defined as the time from the first appearance of a visual stimulus until the athlete’s first movement. MT corresponded to the time from the first movement until the athlete reached the arrival gate (5 m distance).ResultsNo significant between-group baseline differences were observed for RT or MT. Significant group x time interactions were found for MT (p = 0.012, effect size = 0.332, small) for the slower and faster directions (p = 0.011, effect size = 0.627, moderate). Significant pre-to post improvements in MT were observed for NTG but not CG (p = 0.011, effect size = 0.877, moderate). For NTG, post hoc analyses revealed significant MT improvements for the slower (p = 0.012, effect size = 0.897, moderate) and faster directions (p = 0.017, effect size = 0.968, moderate).ConclusionOur results illustrate that 6 weeks of neuromuscular training with two sessions per week included in the warm-up program, significantly enhanced agility performance in elite soccer players. Moreover, improvements were found on both sides during body rotations. Thus, practitioners are advised to focus their training programs on both turning directions.

Isometric Midthigh Pull Characteristics in Elite Youth Male Soccer Players: Comparisons by Age and Maturity Offset.

Morris, RO, Jones, B, Myers, T, Lake, J, Emmonds, S, Clarke, ND, Singleton, D, Ellis, M, and Till, K. Isometric midthigh pull characteristics in elite youth male soccer players: Comparisons by age and maturity offset. J Strength Cond Res 34(10): 2947-2955, 2020-The purpose of this study was to (a) provide comparative isometric midthigh pull (IMTP) force-time characteristics for elite youth soccer players and (b) determine the effect of age and maturation on IMTP force-time characteristics. Elite male youth soccer players (U12 n = 51; U13 n = 54; U14 n = 56; U15 n = 45; U16 n = 39; and U18 n = 48) across 3 maturity offset groups (Pre n = 117; circa n = 84; and Post-peak height velocity n = 92) performed 2 maximal IMTP trials on a portable force platform (1,000 Hz). Absolute and relative values for peak force (PF) and impulse over 100 and 300 ms were analyzed. A full Bayesian regression model was used to provide probable differences similar to that of a frequentist p value. Advanced age and maturation resulted in superior IMTP force-time characteristics. Peak force demonstrated high probabilities of a difference between all consecutive age groups (p > 0.95). For absolute and relative impulse (100 and 300 ms), only 2 consecutive age groups (U14-15's and U16-18's) demonstrated high probabilities of a difference (p > 0.95) with large effects (d = 0.59-0.93). There were high probable differences between all maturity offset groups for PF and impulse with medium to large effects (d = 0.56-3.80). These were also reduced when expressed relative to body mass (relative PF and relative impulse). This study provides comparative IMTP force-time characteristics of elite male youth soccer players. Practitioners should consider individual maturation status when comparing players given the impact this has on force expression.

Strength Profile of Hip Abductor and Adductor Muscles in Youth Elite Soccer Players.

The main objective of this study was to provide an extensive isokinetic profile of the hip joint in youth soccer players, where the literature is limited. Additionally, this study investigated the effect of age on isokinetic peak torque values of hip abductor and adductor muscles and on reciprocal muscle group torque ratios in youth soccer players at different angular velocities (30 vs. 90o/s) and muscle actions (concentric vs. eccentric). Sixty young elite male soccer players were assigned into three equal groups (n = 20): children, young adolescents and older adolescents, and performed five maximal concentric and eccentric hip-abductions and adductions at 30o/s and 90o/s. The results showed a significant increase (p < 0.05) in peak torque values from childhood to adolescence, with the exception of young adolescents vs. older adolescents where no differences were observed. The reciprocal ratios were not affected by age, but improved with an increase in angular velocity with the exception of the CON/ECC ratio that was higher at 30o/s. The data presented in this study provide an extensive isokinetic profile of hip abductor and adductor muscle strength in youth soccer players to assist both coaches and sports medicine professionals in strength monitoring and training.

The Efficacy of Lower-Limb Screening Tests in Predicting PlayerLoad Within a Professional Soccer Academy.

Training exposure has been associated with injury epidemiology in elite youth soccer, where lower-limb musculoskeletal screening is commonly used to highlight injury risk. However, there has been little consideration of the relationship between lower-limb screening and the loading response to soccer activities. To quantify the efficacy of using screening tests to predict the loading elicited in soccer-specific activities and to develop a hierarchical ordering of musculoskeletal screening tests to identify test redundancy and inform practice. Correlational. Professional soccer club academy. A total of 21 elite male soccer players aged 15.7 (0.9) years. Players completed a battery of 5 screening tests (knee to wall, hip internal rotation, adductor squeeze, single-leg hop, and anterior reach) and a 25-minute standardized soccer session with a Global Positioning System unit placed at C7 to collect multiplanar PlayerLoad data. Baseline data on each screening test, along with uniaxial PlayerLoad in the mediolateral, anteroposterior, and vertical planes. Stepwise hierarchical modeling of the screening tests revealed that dominant leg knee-to-wall distance was the most prevalent and powerful predictor of multiplanar PlayerLoad, accounting for up to 42% of variation in uniaxial loading. The adductor squeeze test was the least powerful predictor of PlayerLoad. Of note, one player who incurred a knee injury within 3 weeks of testing had shown a 20% reduction in knee-to-wall distance compared with peers, and elicited 23% greater PlayerLoad, supporting the hierarchical model. There was some evidence of redundancy in the screening battery, with implications for clinical choice. Hierarchical ordering and a concurrent case study highlight dominant leg knee-to-wall distance as the primary predictor of multiaxial loading in soccer. This has implications for the design and interpretation of screening data in elite youth soccer.

Myocardial Performance in Elite Athletes: The Role of Homocysteine, Iron, and Lipids

BackgroundThe myocardial performance index (MPI) is a comprehensive measure of global systolic and diastolic function of the ventricle, and it has an inverse correlation with maximal oxygen consumption. In this study, the potential association between left ventricle MPI and biochemical biomarkers (including iron, homocysteine, and lipids) in elite athletes was investigated.Material/MethodsThis cross-sectional observational study consisted of 80 young male elite soccer and basketball players (age: 18–34 years) examined for a seasonal medical check-up. Cardiological examinations and transthoracic echocardiography of these athletes were performed and blood samples were analyzed according to standard laboratory protocols. Tissue Doppler recording was acquired from the mitral annulus using apical 4-chamber view and then the tissue Doppler-derived MPI was computed.ResultsAthletes were separated into 2 groups based on MPI values (MPI ≤0.40 and MPI >0.40), and baseline demographic, clinical, and biochemical variables of the study participants were compared between these 2 groups. Serum triglyceride, high-density lipoprotein, total cholesterol, homocysteine levels, and iron parameters did not significantly differ between groups, while low-density lipoprotein level was significantly lower in the MPI ≤0.40 group (103.8±26.0 mg/dl vs. 116.8±30.2 mg/dl; p=0.043). Correlation analysis and multivariate linear regression analysis demonstrated a significant association between low-density lipoprotein and MPI.ConclusionsIn this study, various biochemical markers were evaluated for possible association with left ventricle MPI as a surrogate of cardiac performance. Among these biomarkers, only low-density lipoprotein was significantly associated with MPI in elite athletes.

Characteristics of plantar pressure distribution in elite male soccer players with or without history of proximal fifth metatarsal fracture: a case-control study.

[Purpose] Studies have demonstrated a relationship between plantar pressure distribution and proximal fifth metatarsal fracture. We aimed to investigate the plantar pressure patterns of soccer players with or without a history of proximal fifth metatarsal fracture. [Participants and Methods] Fifty-one male soccer players (31 professional, 20 high-school) participated in this study (mean age, weight, and height ± SD: 21.1 ± 4.7 years, 68.8 ± 5.8 kg, and 175.4 ± 5.9 cm, respectively). Seven of them had a history of proximal fifth metatarsal fracture before this study (the fracture group) and 44 had no history of fracture (the control group). A Win-Pod (Medicapteurs) platform was used to measure foot pressure forces. The center of plantar pressure was measured during double and single-limb stances for 25 seconds. Fifth metatarsal pressure and the center of plantar pressure angle was calculated from the walking footprint. The calculated data were compared between the fracture group and the control group. [Results] Comparisons between the fracture and control groups in terms of morphology and the center of plantar pressure length showed no significant differences. However, the fifth metatarsal pressure and the center of plantar pressure angle were significantly higher in the fracture group. [Conclusion] The results of this study revealed that players with excessive loading in the lateral areas of the foot while walking have a risk of developing proximal fifth metatarsal fracture.

Preseason Dynamic Balance Performance in Healthy Elite Male Soccer Players.

Lower limb musculoskeletal injuries in sports are linked with balance abnormalities and altered postural control. Dynamic balance screening should be performed in order to identify athletes at risk. The purpose of the study was to evaluate the preseason dynamic balance performance and side-to-side asymmetry of healthy elite male soccer players, using modified Star Excursion Balance Test (mSEBT). Seventy-three elite soccer players (23.8 ± 5.4 years) were evaluated using the mSEBT. Normalized reach distances, side-to-side asymmetries, and composite scores were determined. The composite scores were 93.33% ± 8.99% for dominant leg and 93.36% ± 9.23% for nondominant leg. No significant differences were found between dominant and nondominant limb in any direction. The mSEBT is an easy-to-use tool to measure the dynamic balance performance in elite athletes. It can be applied successfully during preseason physical examinations. Future studies are needed to establish predictive cutoff points in order to increase mSEBT use in screening soccer players for dynamic balance abnormalities and identify those at risk for noncontact lower limb injuries.

Use of Saliva in Alternative to Serum Sampling to Monitor Biomarkers Modifications in Professional Soccer Players.

We aimed to investigate the correlation between serum and salivary concentrations of steroid hormones and IgA, and the variation in concentrations of these biomarkers, across a soccer competitive season in a sample of players playing for an Italian major League team. Thirty-five elite male soccer players were recruited and assessed for salivary hormones (cortisol, testosterone, T/C‰ and DHEA-S) and IgA at three different time-points: (t1) after the pre-season period and 16 official matches played; (t2) after a winter break and three official matches played; (t3) 2 days after the final match of the championship and 19 matches played. Players were also tested for blood biomarkers (ser-C, ser-T, ser-T/C‰, ser-IgA, ACTH) at two detection times (t1 and t3). Blood samples were collected immediately after saliva sampling. The Spearman’s rank correlation was used to explore the correlation between blood and salivary concentrations of cortisol, free testosterone and IgA in the different time points. One-way ANOVA and permutation test were performed to explore changes by time of hormones and IgA concentrations over the competitive season. We documented a positive correlation between serum and saliva concentrations for Cortisol at t1 (+58.2%; p-value = 0.002) and t3 (+54.2%; p-value = 0.018) and for Testosterone at t1 (+42.0%; p-value = 0.033). Moreover, a positive variation was documented across the season (D = t3–t1) for Cortisol (D = +6.83; SEM = ±2.70; Var% = +37.6; p-value = 0.032), Testosterone (D = +0.33; SEM = ±0.07; Var% = +27.3; p-value = 0.002) and DHEA-S (D = +44.48; SEM = ±18.54; Var% = +82.0; p-value = 0.042), while a decrease of sal-T/C ratio and no variation in salivary IgA concentrations were reported. In conclusion, our findings support for experimental use of saliva samples to monitor steroid hormones modifications in professional soccer players across a competitive season.

Reduced muscle contractile function in elite young soccer players after a short-congested fixture period

Soccer is a very popular sport, which has been widely investigated. However, little is known about the effects of congested fixture periods on muscle mechanical responses since access to elite teams during competitive periods is highly restricted. Thus, the goal of this study was to describe the effects of a short-congested fixture period on the neuromechanical parameters related to fatigue and stiffness of elite young soccer players. Nineteen young elite male soccer players (age 17.13 ± 0.51 years, body mass 69.00 ± 1.22 kg, and height 174.09 ± 0.84 cm) participated in the study. The players took part in a preparatory tournament for the FIFA® U-17 World Cup, composed of a total of six matches in 1 week. Pre- and post-tensiomyographic changes were assessed by means of the normalized response speed (Vrn) and other tensiomyographic markers related to muscle fatigue (i.e. maximum radial muscle displacement (Dm) and velocities of contraction at 10% and 90% (V10 and V90) of both legs in two muscles (biceps femoris and rectus femoris). The players presented a possible to likely impairment in Dm, V10, and V90 of both legs and muscles, with the exception of the non-dominant biceps femoris. Vrn did not vary in any condition, although it presented a slight tendency to decrease. The data demonstrated impairments in the tensiomyographic markers in both legs and muscles, with the exception of the non-dominant biceps femoris. A short-congested fixture period in young soccer players leads to a decrease in muscle stiffness due to cumulative fatigue and lack of muscle recovery, this despite the efforts made by the medical staff to counteract the fatigue caused by the games. The use of tensiomyographic markers could be advantageous for rapidly monitoring neuromechanical muscle impairments throughout competitive soccer periods.

Age-Related Differences in Fitness Performance and Technical Skills of Young Soccer Players

Abstract Introduction . The aim of the study was to identify differences in the level of fitness and technical skills of young soccer players depending on age. Material and methods . The study examined 140 male elite soccer players from the Polish Sport Academy aged 12 to 18 years. Body mass, body height, fitness abilities (5-m, 10-m, and 30-m sprint; envelope run; standing long jump; pull-ups; and beep test) and technical skills (ball handling, juggling alternately with the leg and the head, short passes, and long passes) were measured. Results . Statistically significant (p &lt; 0.05) differences indicating improvement with age were found in older players in speed (15.5%-18.8%), agility (5.7%), lower limb explosive power (39.4%), upper limb strength (254.3%), and cardiorespiratory endurance (31.9%). With regards to technical skills, the greatest progress was documented for long shots (passes) with the internal instep from the ground (140.6% for the dominant leg, DL, and 730.3% for the non-dominant leg, NDL). Slightly lower results were obtained for short shots (passes) with the central instep from the air (128% for DL and 103.6% for NDL) and short shots (passes) with the medial part of the foot (52.1% for DL and 82.8% for NDL), and the lowest were recorded for ball handling with direction change (32.3% for DL and 29.9% for NDL). Conclusions . In the process of talent identification and monitoring of training effects, coaches should take into account the differences in the rate of the development of fitness and technical skills of young athletes.