Male Professional Soccer Players Research Articles

3-Dimensional Biomechanics of Noncontact Anterior Cruciate Ligament Injuries in Male Professional Soccer Players.

The understanding of noncontact anterior cruciate ligament (ACL) injury causation in soccer has improved over the past decades. Bidimensional video analyses have significantly augmented our awareness, representing to date the only practical method to describe injury biomechanics. However, the extent of the problem continues to raise serious concerns. To advance our understanding of the causal pathways leading to ACL injury with a large-scale reconstruction of 3-dimensional (3D) whole-body joint kinematics of injuries that occurred to male elite soccer players, as well as to compare the joint angle time course among situational patterns. Descriptive laboratory study. A total of 33 consecutive noncontact and indirect contact ACL injuries that occurred in 6 national and 2 international professional leagues (seasons 2020-2021 to 2022-2023 until December 2022) were analyzed: (1) multiview noncoaxial television images were inspected; (2) multiple camera views were taken from 400 ms before the initial ground contact to 200 ms after the injury frame; (3) a size-matched pitch was modeled and used to calibrate cameras; (4) a 3D skeletal model was adjusted to fit the player's pose in each frame/view; and (5) poses were interpolated, and Euler joint angles were extracted. The authors reconstructed the 3D lower limb joint kinematic curves preceding and during ACL injuries in 33 cases; notably, a sudden external (up to 5°) and then internal knee rotation was observed after the initial contact and before the injury frame. The overall kinematics at injury were knee moderately flexed (45.9°± 21.7°), abducted (4.3°± 5.1°), and externally rotated (3.0°± 6.4°); trunk shallowly flexed (17.4°± 12.5°) and rotated and tilted toward the injured side; and hip flexed (32.0°± 18.7°), abducted (31.1°± 12.0°), and slightly internally rotated (6.6°± 12.2°). Variable behaviors were observed at the ankle level. Via reconstruction of the sequence of whole-body joint motion leading to injury, we confirmed the accepted gross biomechanics (dynamic valgus trend). This study significantly enriches the current knowledge on multiplanar kinematic features (transverse and coronal plane rotations). Furthermore, it was shown that ACL injuries in male professional soccer players manifest through distinct biomechanical footprints related to the concurrent game situation. Interventions aimed at reducing ACL injuries in soccer should consider that environmental features (ie, situational patterns) affect injury mechanics.

Investigation of Acute Effects of Using Different Density Foam Roller Models on Hamstring Muscle Stiffness and Flexibility in Professional Soccer Players

It was aimed to examine the acute effects of the use of foam roller models of different densities on hamstring muscle stiffness and flexibility in professional soccer players. Hamstring muscle's stiffness were evaluated using the Myoton Pro device. The flexybility of the hamstring muscle were evaluated using with the unilateral sit-reach test on 21 male professional soccer players who played in Gaziantep Soccer Club at aged 18-40. Athletes were randomly divided into groups of seven to use soft, medium and hard foam rollers. The athletes applied the method consisting of two sets of one minute on the dominant hamstring muscle. Measurements were made twice, before the application (BA) and after the application (AA). The muscle stiffness measurement of the soccer players was determined BA mean of 16.26 N/m and AA mean of 16.17 N/m.. Flexibility measurement was determined BA mean of 28,36 cm and AA mean of 31,05 cm. It was found that the mean of pre-test and post-test did not differ statistically for muscle stiffness (p>0,05) according to measurement times, but statistically differed for flexibility (p0,05). It shows that foam roller application is important for increasing muscle flexibility, but there is no difference between foam roller models applied at different intensities in terms of removing muscle stiffness and increasing flexibility.

Unravelling the Relationship between External Load and the Incidence of Hamstring Injuries in Professional Soccer Players

Objectives. The study aimed to analyze external load indicators with the incidence of non-contact hamstring injuries. Material and methods. A non-experimental correlative, retrospective cohort study was carried out. The data were collected from 31 professional male soccer players over the course of one season. The following load indicators were examined: duration (D), total distance travelled (TDT), distance travelled at high intensity (DTHI) > 20km/h, number of efforts between 20-25 km/h (NE 20-25km/h), distance travelled at more than 25km/h (DR+25km/h), number of sprints greater than 25km/h (NE > 25km/h), number of accelerations greater than 1m/s² (Acc), and number of minor decelerations at -1m/s² (Dcc). Only non-contact hamstring injuries were included in the analysis. For the multivariate analysis, we applied a logistic regression model, where a value of P < 0.05 was established both for the statistical significance of the model (X²) and for each of the regressor variables (X²), the confidence interval level was 95%. Results. Two injuries were recorded and diagnosed: injury grade 2 and muscle fatigue. The load indicators analyzed did not show a significant correlation with hamstring injury. Therefore, no association was found between external load and hamstring injury in professional soccer players. Conclusions. The logistic regression model (p > 0.05) did not present statistical significance. Consequently, none of the external load variables monitored explain the rate of non-contact hamstring injuries in this population.

A multi-season machine learning approach to examine the training load and injury relationship in professional soccer

OBJECTIVES: The purpose of this study was to use machine learning to examine the relationship between training load and soccer injury with a multi-season dataset from one English Premier League club. METHODS: Participants were 35 male professional soccer players (aged 25.79±3.75 years, range 18–37 years; height 1.80±0.07 m, range 1.63–1.95 m; weight 80.70±6.78 kg, range 66.03–93.70 kg), with data collected from the 2014–2015 season until the 2018–2019 season. A total of 106 training loads variables (40 GPS data, 6 personal information, 14 physical data, 4 psychological data and 14 ACWR, 14 MSWR and 14 EWMA data) were examined in relation to 133 non-contact injuries, with a high imbalance ratio of 0.013. RESULTS: XGBoost and Artificial Neural Network were implemented to train the machine learning models using four and a half seasons’ data, with the developed models subsequently tested on the following half season’s data. During the first four and a half seasons, there were 341 injuries; during the next half season there were 37 injuries. To interpret and visualize the output of each model and the contribution of each feature (i.e., training load) towards the model, we used the Shapley Additive Explanations (SHAP) approach. Of 37 injuries, XGBoost correctly predicted 26 injuries, with recall and precision of 73% and 10% respectively. Artificial Neural Network correctly predicted 28 injuries, with recall and precision of 77% and 13% respectively. In the model using Artificial Neural Network (the relatively more accurate model), last injury area and weight appeared to be the most important features contributing to the prediction of injury. CONCLUSIONS: This was the first study of its kind to use Artificial Neural Network and a multi-season dataset for injury prediction. Our results demonstrate the potential to predict injuries with high recall, thereby identifying most of the injury cases, albeit, due to high class imbalance, precision suffered. This approach to using machine learning provides potentially valuable insights for soccer organizations and practitioners when monitoring load injuries.

Effects of mid-season camp period loading on sports injury anxiety and physical performance of professional male soccer players

ObjectiveThis study aimed to investigate the effects of 3-week mid-season camp period loading on sports injury anxiety level and physical performances of professional male soccer players. MethodsThirty-four male soccer players [mean age 21.76 (3.42) y] were included in the study. Sports injury anxiety level with the Sports Injury Anxiety Scale, quadriceps muscle strength was assessed with the digital hand dynamometer, flexibility was assessed with the sit-and-reach test, dynamic balance was assessed with the Y balance test, power was assessed with the single-leg jump test, agility was assessed with the t-test, and sprint was assessed with the 20-m sprint test. ResultsThere was no significant difference between the pretest and posttest values of Sport Injury Anxiety Scale scores (p = 0.657). A significant difference was found between the pretest and posttest values of quadriceps muscle strength and dynamic balance (p = 0.040, p = 0.048, respectively). There was no significant difference between the pretest and posttest values of flexibility, single-leg jump, agility, and sprint (p = 0.289, p = 0.128, p = 0.064, p = 0.471, respectively). ConclusionThe 3-week mid-season camp period loading improved quadriceps muscle strength and dynamic balance, but did not affect the sports injury anxiety level, flexibility, jumping performance, agility, and sprint. The results should be considered by sports professionals. It is recommended that further studies be conducted on the effects of different camp period contents, durations and loads in regions with different physical conditions (sea level, high altitude, etc.).

Well-being fluctuations and injuries during an entire season in male professional soccer players: an observational study

ABSTRACT This study aimed to describe and relate the well-being perception and injury incidence of soccer players in an entire soccer season. For 37 weeks, twenty-eight male professional soccer players (25.2 ± 4.3 years old; 22.8 ± 1.4 kg/m2) daily scored (from 1: bad; to 5: perfect) well-being perception (fatigue, sleep, muscle soreness, stress and mood and Hooper Index (HI) as general status). Injuries were also registered. Results showed that players had the lowest well-being perception during Preseason (in terms of HI, fatigue, muscle soreness and stress), being lower than EarlySeason (ps < 0.05, ds > 1.0) and/or InSeason (ps < 0.05, ds > 1.0). The injury incidence was 8.3 ± 9.2/1000 h, being always higher in training compared to competition (35.0 vs 11.1/1000 h). A lower stress perception (worse) correlated with a higher rate of new injuries during PreSeason (r = -0.84), while a greater muscle soreness and fatigue correlated with the new injuries occurring in the following week during the whole season (r = -0.38 and r = -0.39, respectively). As a conclusion, the well-being perception of professional soccer players was especially low during Preseason, with fatigue, muscle soreness and stress as the most affected items that correlated with injury incidence.

The Effect of Primary ACL Reconstruction on Career Longevity in English Premier League and Championship Soccer Players Compared With Uninjured Controls: A Matched Cohort Analysis

Background: Because of the multitude of variables that affect the retirement decisions of professional soccer players, it has proven difficult to isolate the effect of undergoing anterior cruciate ligament (ACL) reconstruction (ACLR) on career longevity. Purpose: To compare the career longevity of professional soccer players after a primary ACLR with that of an uninjured matched control cohort. Study Design: Cohort study; Level of evidence, 3. Methods: A retrospective review of a consecutive series of primary ACLR was performed between 2008 and 2018 in professional male soccer players from the senior author's practice. Each athlete with ACLR was matched to 3 control athletes who had not undergone ACLR according to age, league, playing position, and preinjury game appearances/minutes played. Player career statistics—including league, game appearances, and game minutes—were compiled for each year until retirement or July 1, 2022. Results: A total of 82 soccer players in the English Premier League or Championship at the time of their primary ACLR were matched to 246 control athletes. The mean career length after ACLR was 6 ± 2.6 years, while that of the matched control athletes was 7.6 ± 2.8 years (P < .001). After primary ACLR, an athlete had a 2 times greater chance of retirement compared with the matched control athlete (hazard ratio, 2.19; P < .001). At 5 years after ACLR, 16% of athletes had retired from professional soccer, while 8.5% of the matched cohort were retired (P = .060). By 10 years, 72% of the ACLR cohort had retired compared with 43% of the matched cohort (P < .001). Forwards were more likely to have shortened careers compared with goalkeepers (P = .021); however, no significant differences were observed between midfielders, defenders, and forwards. Within the ACLR cohort, a contralateral ACL tear during the athlete's career caused a 2.30 times (P = .022) increased chance of retirement compared with athletes with only 1 ACL tear during their career. Mechanism of injury, meniscal pathology, graft rerupture, and chondral lesions did not affect career length. Conclusion: Professional male soccer players who underwent ACLR had decreased career length by approximately 1.6 years compared with a matched player cohort.

Recovery After High-Intensity Interval Training in Professional Soccer Players: Passive-Active Combination Recovery Technique

Objective: The aim of this study is to investigate which of the passive recovery (PR), active recovery (AR) and passive-active combination recovery (PAR) techniques applied after the end of high-intensity interval training (HIIT) was more effective in professional super league soccer players. Method: 28 trained professional male soccer players (age: 24.79±2.75 years, height: 180.50±5.81 cm, weight: 74.18±5.47 kg) from the Türkiye Super League team participated in this study voluntarily. Before the study, participants were assigned to 3 groups according to heart rate (HR) and lactic acid (La) levels. Each HIIT load intensity was determined according to the Karvonen method. HIIT sessions were performed for 5 repetitions of 2 minutes (1 set = 5x2 minutes) and a 30-second rest was given between repetitions. At the end of the set, a 2-minute recovery period was applied. Three different recovery techniques, PR, AR and PAR, were applied alternately to each group at the end of the HIIT programs. Participants' HR and La values were taken at the end of HIIT and recovery techniques. Differences between the obtained data were determined by repeated measures one-way ANOVA and multiple comparison tests. P&lt;0.05 level was considered significant in all tests. Results: Although there was no significant difference in La levels between groups (p&gt;0.05), significant differences were observed between HR and loading intensities (p&lt;0.05). According to the results of multiple comparisons, the recoveries in HR and La levels were found to be significant in favor of the PAT group (p&lt;0.05). Discussion: It can be thought that football players increase the mitochondrial biogenesis, oxidative and lipid oxidation capacities of skeletal muscles due to adaptations to HIIT and similar heavy workouts. Depending on these developments in the athletes' condition, it can be said that all three recovery techniques affect the decrease of HR and La in the two-minute period. Conclusion: PR and PAR techniques were effective in reducing HR levels. AR and PAR techniques were effective in reducing La levels. Therefore, it can be said that the PAR technique is more effective in reducing both HR and La levels together.

Identifying the ideal weekly training load for in-game performance in an elite Brazilian soccer team.

Introduction: The purpose of this study was to investigate the ideal training load to be applied during periods of fixture congestion to ensure an adequate dose-response effect for performance maintenance. Methods: Match performance data and corresponding pre-match training load sessions (both N = 498 match performance cases and training-block session cases) were collected (with the catapult system, VECTOR7) from 36 male professional soccer players (23.5 ± 5.2 years; 178 ± 4cm; 75.5 ± 6.0kg) belonging to the Brazilian First Division team during the 2022 season. The following data were collected in match and training sessions: jump, acceleration, deceleration, and change of direction (COD); running distance producing metabolic power at different intensities (>20, >20-35, >35-45, >45-55, and >55Wkg-1), total distance (m), relative distance (m/min), running distance at different speeds (>20, >25, and >30km/h), number of sprints (running >25km/h), and maximum speed (km/h). Mixed linear model (MLM), decision tree regression (DTR), and cluster K means model (SPSS v.26) approach were performed to identify the most critical variables (and their respective load) in the training sessions that could explain the athlete's match performance. Results: MLM and DTR regression show that training load significantly affects game performance in a specific way. According to the present data, an interference phenomenon can occur when a high load of two different skills (running in a straight line vs COD, deceleration, and jumping) is applied in the same training block of the week. The cluster approach, followed by a chi-squared test, identified significant associations between training load and athlete match performance in a dose-dependent manner. Discussion: The high load values described here have a beneficial effect on match performance, despite the interference between stimuli discussed above. We present a positive training load from a congested season from the Brazilian First Division team. The study suggests that an interference effect occurs when high physical training loads are applied to different specific physical skills throughout the season.

Neurocognitive Errors and Noncontact Anterior Cruciate Ligament Injuries in Professional Male Soccer Players.

Evidence is emerging that core neurocognitive functions such as working memory and inhibitory control (ie, motor-response and attentional inhibition) are linked to the anterior cruciate ligament (ACL) injury risk. Research has been conducted in laboratory settings, but the contribution of neurocognition to actual ACL injuries under real-world conditions is unknown. To describe the possible neurocognitive errors involved in noncontact ACL injury mechanisms. Case series. Soccer matches. A total of 47 professional male soccer players. Three independent reviewers evaluated 47 videos of players sustaining noncontact ACL injuries. Neurocognitive errors in inhibitory control were operationalized as follows: (1) motor-response inhibition was scored when a player demonstrated poor decision-making and approached the opponent with high speed that reduced the ability to stop or change the intended action and (2) an attentional error was scored when a player shifted his selective attention away from the relevant task to irrelevant stimuli. Of 47 noncontact ACL injuries, 26 (55%) were related to a pressing-type injury, 19 (73%) of which involved a deceiving action made by the opponent, suggesting poor inhibitory control of the defender. Of the remaining 21 noncontact ACL injuries (45%), 16 (76%) could be attributed to attentional errors. Agreement among the 3 raters was very good for all items except poor decision-making, which showed fair to good agreement (Fleiss κ = 0.71). Interrater reliability was excellent (intraclass correlation coefficient = 0.99-1.00). Errors in motor-response inhibitory control and attentional inhibition were common during noncontact ACL injury events in professional male soccer players. The interrater agreement in detecting neurocognitive errors in general was very good.

Knee Biomechanics During Neurocognitively Challenged Drop Landings in Male Elite Soccer Players with Anterior Cruciate Ligament Reconstruction.

Reactive decision-making during athletic movement has been demonstrated to evoke unfavorable biomechanics associated with anterior cruciate ligament (ACL) rupture. However, the current evidence is based on assessments of healthy individuals. We aimed to investigate unplanned jump landing kinetics and knee kinematics in ACL-reconstructed (ACLR) and non-injured athletes. A total of 30 male professional soccer players (n = 15 ACLR after return to play, n = 15 matched controls) performed six drop landings onto a force plate. As a neurocognitive challenge requiring decision-making, a diode flashing in randomly selected colors indicated the requested landing location. Knee joint kinematics (flexion, valgus and tibial rotation angles) assessed with a 10-camera motion capture system, vertical ground reaction force (vGRF), time to stabilization (TTS) and length of the center of pressure (COP) trace (all analyzed from force plate data) were calculated. Cognitive function was assessed using the CNS Vital Signs battery. The ACLR group produced lower knee flexion angles than the control group (median [interquartile range] 50.00° [6.60] vs. 55.20° [4.45], p = .02). In addition, path length of the center of pressure (379mm [56.20] vs. 344mm [37.00], p = .04) and ground reaction force (3.21 N/kg [0.66] vs. 2.87 N/kg [0.48], p = .01) were higher for the ACLR group. No differences were found for knee valgus (p = .96), tibial rotation (p = .83) and TTS (p = .82). ACLR participants scored lower for reaction time (p = .02) and processing speed (p = .01). Unfavorable knee biomechanics were more often related to cognitive function in the ACLR group than in the control group (p < .05). Impaired reactive decision-making during athletic movement may contribute to the high re-injury risk in individuals with ACLR. Prospective studies confirming potential cause-effect relationships are warranted.

Match-Play Running Performance in Professional Male Soccer Players: The Role of Anaerobic Speed Reserve

ABSTRACT Purpose: This study aimed to compare match-play running performance between players with a high (HASR) and low (LASR) anaerobic speed reserve (ASR) profile in professional soccer players. Method: Thirty-six male players from the same club (age: 23.3 ± 5.4 years) took part in this study. Match data were collected from 43 home matches of the first and second division of the Brazilian National Championship over two consecutive seasons. Players had their maximal sprinting (MSS) and aerobic speeds (MAS) determined during field test-based assessments. ASR was defined as MSS minus MAS. Total distance (TD), sprinting distance, number of accelerations and decelerations, absolute peak (PMS(abs)) and mean match sprint speed (MMSS(abs)) and its relative values expressed as a percentage of MSS (PMS(rel) and MMSS(rel)), distance covered > 100% MAS(abs) and > 50% MSS(abs) were compared between the groups and halves. Results: HASR presented greater sprint demand (d > 0.80), PMS(abs) (d = 1.57), and MMSS(abs) (d = 0.99) than the LASR group. The opposite was observed for PMS(rel) and MMSS(rel). The TD and amount of high-intensity accelerations and decelerations were moderately (0.77<d < 0.90) and largely (1.21<d < 1.63) reduced between halves for HASR and LASR, respectively. LASR players also had their distance >MAS(abs) and > 50% MSS(abs) decreased between halves (d = 0.72 and 0.77), while the HASR did not (d < 0.10). Conclusion: Our findings indicated that players with larger ASR had greater sprint demand, with a lower relative running intensity, and covered longer distances above MAS. The amplitude of ASR also affected the player’s running ability between halves.

Comparisons of external load variables among periods, playing status, and positions in professional soccer team: A case study

The aims of this study were to compare weekly variations of training monotony (TM) and training strain (TS) among periods of the season, playing status and playing positions in professional soccer athletes. Nineteen male professional soccer players were monitored daily over a 43-week period for their total distance, sprint distance (&gt;23 km h−1), acceleration (Acc, &gt;4 m s−2), and decelerations numbers (Dec, &gt;−4 m s−2). Players were divided in groups of 10 starters and 9 non-starters; and by three central defenders (CD), four wide defenders (WD), four central midfielders (CM), four wide midfielders (WM), and four strikers (ST). Season data was divided in pre-, early-, mid-, and end-season. There were significant differences for TM through sprint distance between playing positions in mid- and full-season. In mid-season, sprint distance was meaningfully greater for CD than WD ( p = 0.006; g = 1.74 [0.06, 3.95]), CM ( p = 0.002; g = 2.04 [0.28, 4.46]), WM ( p = 0.005; g = 1.78 [0.09, 4.02]), and ST ( p = 0.002; g = 2.05 [0.28, 4.46]). Regarding full-season, TM of sprint distance was significantly greater for CD than WD ( p = 0.031; g = 1.59 [−0.04, 3.73]), CM ( p = 0.011; g = 1.83 [0.13, 4.11]), and ST ( p = 0.023; g = 1.52 [−0.10, 3.59]). The study revealed that TM and TS of sprint distance in mid-season was meaningfully greater for CD than for WD, CM, WM, and ST. No differences between starters and non-starters were found.

The impact of a multicomponent training program on physical fitness and joint injuries in Spanish male professional soccer players

ABSTRACT This study aimed to assess the effects of a multicomponent training program (ProSAS) on selected measures of physical fitness and joint injuries in Spanish male professional soccer players. Twenty-six professional soccer players (age: 25.2 ± 3.1 years) were randomly assigned to either the experimental (EG; n = 16) or control group (CG; n = 10). Y-balance test (YBT), Single leg countermovement jump (SLCMJ), Single leg hop for distance test (SLH), Side-hop test (SH), Speedy jump test (SpJ), Agility T-test (TT) and Lower extremity functional test (LEFT) were performed before and after an 8-weeks training period. Additionally, any joint injury occurring during the intervention period were recorded. Significant improvements in the EG in all tests (p = 0.001 to p = 0.014), except for SLCMJ (p = 0.632) with the dominant leg were observed. CG displayed decreases in SLCMJ with the non-dominant leg (p = 0.014), SH for both legs (p = 0.001 to p = 0.050), TT (p = 0.005), and LEFT (p = 0.001). Inter-groups differences revealed better results for the EG in all variables (p = 0.001 to p = 0.008) except from SLCMJd (p = 0.555). Moreover, the EG exhibited lower joint injury incidence and burden compared to the CG (p < 0.05). These findings suggest that the ProSAS is an effective multicomponent program to improve variables related to risk of joint injuries, and consequently, to reduce the incidence and burden of these injuries in professional soccer players.

Sweat Rate, Sweat Sodium Losses, and Body Composition in Professional Male Soccer Players in Southwest Colombia.

Background and Objective: Dehydration and hyperhydration impact athletes' performance. Exploring the fluid balance concerning body composition might help estimate individual hydration requirements. This area of research, particularly regarding sodium losses, has been relatively understudied. We evaluated the sweat rate (SR), sweat sodium losses, and their relationship with body composition in professional soccer players in Cali, Colombia. Materials and Methods: Thirty-two male players, aged 24.3 (±5.2) years, from the Colombian main soccer league, underwent high-intensity training at 32 °C (with a relative humidity of 79%). The outcome variables included SR, calculated using weight loss and fluid intake; forearm sweat sodium concentration (FSCC), measured through the direct ion-selective electrode method; and estimated the predicted whole sweat sodium loss (PWSSL) in mmol. Predictor variables (body mass, fat, and muscle masses) were estimated using the Deborah Kerr anthropometry method. The association between predictors and outcomes was assessed using linear regression. Results: The mean FSCC, PWSSL, and SR were 26.7 ± 11.3 mmol/L, 43 ± 15.9 mmol/L, and 1.7 ± 0.5 L/h, respectively. Body mass positively predicted FSCC in unadjusted and age/fat-mass-adjusted models [Beta 1.28, 95% confidence interval (CI) 0.39-2.18, p = 0.006], and continued related to FSCC after adjustment for muscle mass with marginal significance [Beta 0.85, 95% CI -0.02 to 1.73, p = 0.056]. Muscle mass was associated with the PWSSL in unadjusted and age/fat-mass-adjusted models [Beta 2.42, 95% CI 0.58-4.26, p = 0.012] and sustained an association with marginal statistical significance after adjustment for body mass [Beta 1.86, 95% CI -0.35 to 4.09, p = 0.097]. Conclusions: Under hot tropical weather conditions, FSCC was relatively low among the players. Body mass was better associated with the FSSC, and muscle mass better related to the PWSSL. Body and muscle masses could be regarded as potential factors to be explored in the estimation of individual sodium needs. However, further studies are required to validate and contrast our findings.

DOPING CONTROL IN MALE SOCCER PLAYERS IN BRAZIL: 10 YEARS OF FOLLOW-UP.

To understand the Adverse Analytical Finding (AAF) that have occurred in Brazilian soccer in a recent 10-year period, comparing them to international data, to know the Brazilian profile. A review of the AAR in the Doping Control Commission database of the Brazilian Football Association from 2008 to 2017. The AAR in professional male soccer players between 2008 and 2017 were considered. The sample selected in this research was composed of 40,092 doping tests, with 113 AAR, identified in 18 different competitions (0.28%) in the professional category, in Brazilian national and state competitions between 2008 and 2017, flagged in doping control exams through urine samples. Stimulants were detected most frequently (31.0%), followed by glucocorticoids (21.2%), diuretics, and masking agents (19.5%). The Brazilian Championship series did not show a relationship with any of the World Anti-Doping Agency (WADA) groups of substances. Series A showed 0.07% of AAR, Series B 0.21%, Series C 0.75% and Series D 1.49. The rate of AAR in Brazilian soccer was 0.28%, lower than the average for all soccer worldwide, and shows similar percentages among field positions. Stimulants were the most prevalent drugs. The national elite soccer competitions showed significantly fewer cases than the lower divisions. Level of Evidence II; Retrospective Study.

Testing variations between starters and substitute players in terms of total distance, high-speed running, and sprinting distance: a descriptive study on professional male soccer players.

The purpose of this study was three-fold: (i) to compare total distance, high-speed running (HSR) distance, and sprint distance covered per 5-minute epoch by players acting as both starters and substitutes; (ii) to compare the locomotor demands between the moments the players entered the match (45-60, 60-75 and 75-90 minutes); and (iii) to compare the locomotor demands of the players between the variations of the within- and between-playing positions. Twenty-one male professional soccer players competing in the Professional Premier League of one of the European countries were observed over sixteen official matches. The players were monitored during all matches using a Global Navigation Satellite System. The measures collected were total distance (TD; m), distance in HSR, sprint distance, HSR, and sprint counts. Considering the comparisons between the splits over the second half of match play, a significant difference between the starters and the substitutes was observed only for sprint distance in the 90-95 minute split (Z = -2.023; p = 0.043). Moreover, no substantial differences were found between the moment the substitute player entered the match regarding total distance (H = 2.650; p = 0.266), HSR distance (H = 1.738; p = 0.419), and sprint distance (H = 0.048; p = 0.976). However, the comparison of between-playing positions revealed considerable differences in total distance (H = 29.246; p < 0.001), and HSR distance (H = 12.153; p = 0.002) covered by the players acting as starters. In contrast, for substitute players, such differences were reported in HSR distance (H = 27.892; p < 0.001) and sprint distance (H = 15.879; p < 0.001). In conclusion, this study suggests that acting as a starter or a substitute does not significantly affect the intensity of effort except during the last periods of match play. However, the contextual factor of performing in a specific playing position plays a significant role both for starters and substitutes.

Treating Dystonia in a Soccer Player Through an Integrated Rehabilitative Approach: A Case Report.

Sport-related dystonia is a rare form of activity-specific dystonia that can severely impair an athlete's ability to perform. Due to a lack of data on the condition, it is difficult to diagnose and often overlooked, and no gold standard treatment has yet been defined. We present a rare and challenging case of sport-related dystonia that affected a 24-year-old male professional soccer player. The patient presented with severe rigidity and dystonia of the right lower-extremity, particularly the ankle and foot. The symptoms set on >1year prior to the presentation to our outpatient clinic. He began to complain of stiffness and difficulty moving his lower limbs, especially his right leg, initially when playing soccer, but then also when walking normally. On presentation, he was unable to run and walked with difficulty, supporting his body weight only on the outside of his right foot. He also reported a motor trick and reverse motor trick involving the oral musculature in order to move his lower limb more freely. An integrated rehabilitation approach based on postural rehabilitation, neuromuscular rehabilitation, and dental intervention was used to successfully treat this condition. The approach included: (1)postural rehabilitation with the Mézières-Bertelè method to reduce muscular stiffness, (2)neuromuscular re-education with Tai Chi exercises and electromyography-guided biofeedback, and (3)dental intervention and swallowing rehabilitation to limit impaired oral habits (due to the relationship between his impaired lower limb movements and motor tricks of the oral musculature). After 7months of integrated rehabilitation, the patient returned to professional soccer. This case report highlights the potential efficacy of an integrative rehabilitation approach for sports dystonia, particularly in cases where traditional treatments may not be effective. Such an approach could be considered a valuable option in the management of this rare, but debilitating, condition in athletes. Further research is needed to assess the effectiveness of this approach in larger populations.

The Quantification of Physical Performance and Internal Training Load in Youth Male Soccer Players During Preseason.

The monitoring of training loads and quantification of physical performance are common practices in youth soccer academies to support coaches in prescribing and programming training for individuals. The interaction between training load and physical performance is unknown during a preseason period in youth soccer players. The current study assessed changes in training load and physical assessments across a 4-week preseason period. The relationship between physical performance and match playing time in youth male soccer players was also investigated. The training loads of 25 professional youth academy male soccer players were monitored throughout a 4-week preseason period. Assessments of power, agility, speed, and aerobic capacity were undertaken in the first training session. Session ratings of perceived exertion (sRPE) and well-being questionnaires were collected during all training sessions and preseason matches. Playing time during subsequent competitive matches was recorded. T test and 30-m-sprint assessments, conducted on the first day of preseason, were predictors of sRPE throughout preseason (t test χ2/df = 2.895, poor adjustment; 30-m sprint χ2/df = 1.608, good adjustment). YoYo Test performance was related with changes in perceived fatigue (χ2/df = 0.534, very good adjustment). Faster players reported higher values of sRPE, and players with higher aerobic capacity reported higher levels of fatigue across preseason. Well-being, perceived fatigue and soreness, and sRPE decreased across preseason. Greater match durations were related to higher levels of fatigue during preseason (P < .05). The current study highlights the relationship between training load, physical assessments, and playing time. Coaches and practitioners can use physical test data at the start of preseason as an indication of players that report higher sRPE, perceived fatigue, and reduced well-being across preseason, supporting decisions around individualized training prescriptions.

Lower limbs strength variations between injured and non-injured professional soccer players.

Due to its physical demands, professional soccer is becoming a real challenge regarding players' exposure to high injury risk. Given its tight correlation with high-intensity actions, muscular strength is a crucial physical characteristic for soccer players. Therefore, the aims of this study are (a) to compare the vertical jumping performance during the season according to the injury profile, and (b) to investigate differences in isokinetic strength performance at the beginning and the end of the season. Twenty-one male professional soccer players (age: 26.0 ± 4.1 years, height: 181.0 ± 6.9 cm, body mass: 73.7 ± 6.9 kg) were assessed in isokinetic strength (Biodex System 4 Pro Dynamometer), and Optojump Next (Microgate, Bolzano, Italy). Isokinetic strength analyses considered the peak torque scores of knee flexors and knee extensors, according to the player's preferred and non-preferred limb. The countermovement and squat jump maximum height were assessed as lower body explosive strength indicators. No significant differences were found when comparing injured and non-injured players in vertical jump and isokinetic strength assessments. However, significant results were found when comparing both groups' initial and final evaluation in isokinetic strength assessment, with both groups significantly improving their performance. Our findings indicate that the overall lower body strength performance was not a discriminant factor between injured and non-injury players. Thus, muscular strength assessment performance increased throughout the season independently of the injury profile. Future research needs to integrate other variables related to sports injuries since they seem to result from multifactorial causes.