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This study examined the relationship between motor competence (MC) and Landing Error Scoring System (LESS) performance in a sample of male junior grassroots footballers aged 10-13 years. Ninety-eight boys aged 10-13 years (mean ± SD = 11.7 ± 1 years) undertook assessment of MC, using the Test of Gross Motor Development (third edition) and anterior cruciate ligament (ACL) injury risk using the LESS. Height and mass were assessed from which maturity status was predicted. Multiple backward linear regressions indicated a significant model (p = 0.001), which explained 49% of the variance in LESS scores. Locomotor MC (β = -0.538, p = 0.001), object control MC (β = -0.261, p = 0.004), and age (β = 1.17, p = 0.03) significantly contributed to the model. Maturity offset (p = 0.100) was not significant. Analysis of covariance (controlling for age and maturity offset) indicated a significant difference in locomotor MC between those classified as poor for LESS. A similar result was observed for object control MC (p = 0.003, ηp² = 0.09), where those classed as poor for LESS had significantly poorer object control MC compared with those classed as excellent, good, and moderate. The results of this study indicate that there is a relationship between both locomotor and object control MC and errors in drop jump landing mechanics in boys aged 10-13 years, with MC explaining nearly 50% of the variance in LESS scores. Practically, this study indicates that MC, particularly locomotor MC, has potential to identify performance in jump landing tests that are associated with increased risk of ACL injury in boys who play grassroots soccer. [ABSTRACT FROM AUTHOR]

This retrospective study aimed to examine the effect of transcranial direct current stimulation (tDCS) combined with lower limb pneumatic compression during the postmatch recovery period in top-level professional male soccer players' physiological and perceptual markers of recovery status. During the 2022 season (baseline), pneumatic compression was performed as part of the recovery strategy, applied the day after official match play and psycho- physiological measurements (pain, sleep, perceived recovery, and creatine kinase [CK] sampling) were performed on the second day postmatch. During the 2023 season, the tDCS protocol was introduced, with its application being performed simultaneously (in conjunction) with pneumatic compression. Recovery sessions following 10 matches in the 2022 season and following 10 matches in the 2023 season were included in the analyses. Compared with 2022 (baseline; pneumatic compression isolated), the players perceived an increased recovery on the second day postmatch when tDCS was used in conjunction with the pneumatic compression (mean = 12%; p = 0.008) and rated improved sleep quality for the nights after applying tDCS combined with pneumatic compression (mean = 7.5%; p = 0.029). On the second day postmatch, a significant reduction was observed in muscle pain/soreness (mean = 64%; p < 0.0001) and the CK concentration decreased when baseline (pneumatic compression isolated) was compared with tDCS + pneumatic compression (mean = 76%; p = 0.001). In summary, combining pneumatic compression with tDCS may enhance the effects of both interventions, leading to greater overall improvements in recovery. Further research is warranted to confirm these findings and explore the underlying mechanisms in more detail. [ABSTRACT FROM AUTHOR]

Objective: To describe the epidemiology of hamstring tears in National Collegiate Athletic Association (NCAA) sports. Design: Descriptive epidemiology study. Athletic trainers from NCAA schools reported injuries to the NCAA Injury Surveillance Program. Setting: A convenience sample of NCAA hamstring tear injuries during the 2014/2015 through 2018/2019 academic years. Patients (or Participants): NCAA student-athletes. Independent Variables: Sport, sex, event type, season segment, injury history, and activity at the time of injury. Main Outcome Measures: Injury counts, rates, and proportions were used. Results: Two thousand ninety-six hamstring tears from 8 474 400 athlete-exposures (AEs) were reported (2.47 per 10 000 AEs). Rates were highest in Men's Soccer (5.97 per 10 000 AEs) and Women's Soccer (3.13 per 10 000 AEs), among all Men's and Women's sports, respectively. Competition-related rates in Men's and Women's sports were highest in 2015 to 2016 then followed a decreasing pattern across the remainder of the study period. Among sex-comparable sports, rates were higher in men's (compared with women's) Baseball/Softball, Soccer, and Track and Field. The prevalence of recurrent injuries was comparable among men's (14.8%) and women's (11.5%) sports. Time loss hamstring tears were more prevalent in Men's sports than Women's sports [injury proportion ratio 5 1.33; 95% confidence interval, (1.21, 1.47)]. Conclusions: Overall, hamstring tear rates were higher across all Men's sports compared with Women's sports. Rates across event type were comparable in several sports; and so, adjustments to practice are needed considering that practice environments are more modifiable than competitions. Indeed, improving hamstring tear prevention programs to reduce the burden of this injury in NCAA athletes remains critical. [ABSTRACT FROM AUTHOR]

Objective: To compare the exercise intensity of walking football (WF) with walking (WA) and to describe specific movement characteristics of WF. Design: Cross-sectional study. Setting: Sports facilities Saarland University, Germany. Patients: Eighteen patients with cardiovascular risk factors CVRFs and diseases (13 men and 5 women, age: 69610 years). Independent variables: Patients completed a WF match and WA session of 2 x 10 min each. Video analysis was used to characterize movements during WF. Main OutcomeMeasures: Rate of perceived exertion (RPE, Borg Scale 6-20),%maximum heart rate (HRmax), musculoskeletal pain on a visual analog scale (VAS, 1-100 mm) before and up to 72 hours after exercise, and movement patterns during WF. Results: The mean RPE during WF (12.1 6 2.7) and WA (11.9 6 3.0) did not differ (P 5 0.63). The mean HR during WF (79612% of HRmax) was higher than duringWA(71%611%; P, 0.01). The HR variability coefficient of variation during WF (10.3% 6 5.8%) and WA (7.1 6 5.5%) did not differ (P 5 0.13). There was no influence of exercise mode (WF vs WA) on musculoskeletal pain perception (P 5 0.96 for interaction). Injury-inciting activities such as lunges (median: 0.5 [interquartile range (IQR) 0-1.3]) and goal kicks (median: 4 [IQR: 1.8-5.3]) occurred rarely during WF. Conclusions: Walking football might represent an alternative to WA for health prevention programs in patients with CVRF and diseases as it is characterized by a manageable cardiocirculatory strain, moderate RPE, low pain induction, and a low number of injury-inciting activities. [ABSTRACT FROM AUTHOR]

Patellofemoral disorders are common in the world of soccer and impact players across all levels and ages of the sport. Patellofemoral disorders encompass a spectrum of conditions, from anterior knee pain to patellar instability, and are often influenced by complex biomechanical factors and anatomic variations that can predispose to these conditions. in recent years, there has been a growing emphasis on injury prevention strategies and data-driven approaches, championed by organizations like the Union of European Football Associations and individual professional clubs. conservative management remains the initial approach for many players, including physical therapy and supportive devices. However, surgical intervention, particularly in cases of recurrent patellar dislocations, is often necessary. The understanding of patellofe-moral biomechanics in soccer continues to evolve and offers opportunities for more effective injury prevention and tailored treatment strategies. Despite the challenges, a comprehensive approach to patellofemoral disorders in soccer is essential to preserve player health, enhance performance, and sustain the sport's vitality. [ABSTRACT FROM AUTHOR]

Anterior cruciate ligament (ACL) injuries to soccer players present unique challenges in sports medicine, given the sport's global prevalence and intricate injury dynamics. These injuries, especially in the youth and female demographic, have become a substantial concern in sports medicine. This review explores the epidemiology, mechanism of injury, diagnostic procedures, treatment modalities, and rehabilitation strategies related to ACL tears within the soccer community. Progress in diagnostics, treatments, and rehabilitation underscores the importance of evidence-based approaches. As soccer continues its ascent in popularity, addressing the specific risks and nuances of ACL injuries in this context remains of paramount significance. [ABSTRACT FROM AUTHOR]

Soccer is considered the most popular sport in the world. The game involves frequent agile maneuvers, such as rapid accelerations/decelerations and pivoting, and carries an inherent risk of high-speed collisions, which can lead to lower extremity injury. Knee and meniscus injuries can cause significant pain and disability, precluding participation in the sport. Understanding the diagnosis and management of meniscal injuries in soccer players is essential to the care of these athletes. This paper reviews meniscal anatomy, biomechanics, and mechanisms of injury; discusses the work-up, diagnosis, and management of meniscus injuries; and reports on rehabilitation, return to sport, and outcomes after meniscal injuries in soccer players. [ABSTRACT FROM AUTHOR]

Implicit learning has the potential to improve movement execution and reduce injury risk. Previous research showed beneficial effects of short-term interventions with implicit learning in male athletes. However, research on long-term interventions in female athletes is lacking. The aim of this study was to examine the effects of a 4-week intervention with video instruction on movement execution of SSC, a task that is highly related with anterior cruciate ligament (ACL) injury risk, in female athletes. Twenty talented adolescent female soccer players were part of the control (CTRL, n = 10) or video instruction (VIDEO, n = 10) group. All subjects practiced 4 weeks and received general task instructions. In addition, the VIDEO group received expert video instruction during practice. Lower extremity kinematics and kinetics and vertical ground reaction force of SSC were examined during baseline, immediate post, and 1-week retention tests. After nonlinear registration, differences between each subject and the expert she had seen were determined. These differences were analyzed with SPM1D 2-way ANOVA. No interaction effects between time and group were found (p > 0.05). Main effects of time were found in the frontal plane. In particular, smaller deviations of subjects compared with the seen expert of the knee adduction (p = 0.005, 97.9-100% stance phase [SP]) and hip abduction (p = 0.005,11.5-13.8% SP) and adduction (p < 0.001, 33.4-87.7% SP) moments were found in immediate post compared with baseline. These frontal plane short-term improvements, replicating earlier findings in both sexes, may lower ACL injury risk. The large observed interindividual differences overtime may have concealed the long-term effects of video instruction at the group level. [ABSTRACT FROM AUTHOR]

Field referees (FRs) need to move throughout the pitch to identify any infringements of the game's laws. Their performance depends on technical, tactical, physical, physiological, and mental factors. This retrospective study aimed to examine and assess the physical and physiological parameters as a function of time in elite association football referees during official matches. Global positioning system (match time, distance in different intensity ranges [low-intensity, high-speed, very high-speed running, and sprinting], average and peak speed, distance in accelerations or decelerations) and heart rate (average and peak) data from 212 national and international football matches were analyzed. A linear mixed-model analysis was performed to assess the differences between halves and between the three 15-minute sections of each half-time for all the physical and physiological variables collected. A significant effect of match half was found for the game time (p < 0.001) and the standing time (p = 0.005), both higher in the second half, and for the average speed (p = 0.017), which was lower in the second half. Total distance (p < 0.001), low-intensity distance (p = 0.004), and average speed (p = 0.007) all showed a reduction as a function of time. More than 7.800 high-speed intervals were detected. Accelerative actions within 3 seconds characterized most of the high-speed efforts of an FR during a match. Significant differences emerged in the way the match intensity is distributed across the match, analyzed both in halves (first vs. second) and 15-minute intervals within each half. It is important to emphasize the importance of high-speed training with a focus on a faster transition from low- to high-speed running to keep up with the play to get into an appropriate position and subsequently make the correct decisions. [ABSTRACT FROM AUTHOR]

The aim of this study was to quantify the session rating of perceived exertion (sRPE), duration, and training load accrued across typical training weeks undertaken by youth soccer players. Differences between starters, nonstarters, and variations in training load variables were also investigated. Data were collected from 230 elite youth players in 4 age groups (U15, U16, U17, and U19) during 5 competitive seasons. Mixed models were used to describe variation between age groups and compare starters with nonstarters, with season as a fixed covariate effect. Week-to-week variation in training load was expressed as the percentage coefficient of variation. The main findings may be used to highlight a significant effect of age and playing status on training intensity, duration, and internal training load. Weekly training load increased progressively from the U15 to U17, with significant differences between each age group (p < 0.03). Lower mean weekly perceived intensity (sRPE) was noted in U15 when compared with the older age groups (4.2 vs. 4.6-4.9 arbitrary unit for U16 to U19, p < 0.001). Low weekly training load variation was observed across the different phases of the season in each age group, with the preseason exhibiting the greatest variance (3.6-6.2%). Differences in the training load are likely more attributable to changes in training duration rather than sRPE. Control of session duration seems to play an important role when aiming to control load in the academy environment, and practitioners should closely monitor the differences in duration and load being recorded between starters and nonstarters. [ABSTRACT FROM AUTHOR]

Identifying fast athletes is an important part of the National Football League (NFL) Combine. However, not all athletes partake in the 36.58-m sprint, and relying on this single test may miss potentially fast athletes. Therefore, the purpose of this study was to determine whether sprinting times can be predicted using simple anthropometric and jumping measures. Data from the NFL Combine between the years 1999-2020 inclusive were used (n = 4,149). Subjects had a mean (±SD) height = 1.87 ± 0.07 m and body mass = 111.96 ± 20.78 kg. The cross-validation technique was used, partitioning the data into a training set (n = 2,071) to develop regression models to predict time over the 9.14-, 9.14-to 18.29-, 18.29-to 36.58-m, and 36.58-m segments using vertical jump, broad jump, height, and mass as the independent variables. The models were then evaluated against a test set (n = 2,070) for agreement. Statistically significant (p < 0.01) models were determined for 9.14-m time (adjusted R² = 0.76, SEE = 0.05 seconds), 9.14- to 18.29-m time (adjusted R² = 0.74, SEE = 0.04 seconds), 18.29- to 36.59-m time (adjusted R² = 0.79, SEE = 0.07 seconds), and 36.58-m time (adjusted R² = 0.84, SEE = 0.12 seconds). When evaluated against the test set, the models showed biases of -0.05, -0.04, -0.02, and - 0.02 seconds and root-mean-square error of 0.07,0.05,0.07, and 0.12 seconds for the 9.14-, 9.14-to 18.29-, 18.29-to 36.58-m, and 36.58-m segments, respectively. However, 5-6% of the predictions lay outside of the limits of agreement. This study provides 4 formulae that can be used to predict sprint performance when the 36.58-m sprint test is not performed, and practitioners can use these equations to determine training areas of opportunity when working with athletes preparing for the NFL Combine. [ABSTRACT FROM AUTHOR]

Background and Purpose: Sport-specific training may improve postural control, while repetitive head acceleration events (RHAEs) may compromise it. Understanding the neural mechanisms underlying postural control may contextualize changes due to training and RHAE. The goal of this study was to determine whether postural sway during the Balance Error Scoring System (BESS) is related to white matter organization (WMO) in collegiate athletes. Methods: Collegiate soccer (N = 33) and non-soccer athletes (N = 44) completed BESS and diffusion tensor imaging. Postural sway during each BESS stance, fractional anisotropy (FA), and mean diffusivity (MD) were extracted for each participant. Partial least squares analyses determined group differences in postural sway and WMO and the relationship between postural sway andWMOin soccer and non-soccer athletes separately. Results: Soccer athletes displayed better performance during BESS 6, with lower FA and higher MD in the medial lemniscus (ML) and inferior cerebellar peduncle (ICP), compared to non-soccer athletes. In soccer athletes, lower sway during BESS 2, 5, and 6 was associated with higher FA and lower MD in the corticospinal tract, ML, and ICP. In non-soccer athletes, lower sway during BESS 2 and 4 was associated with higher FA and lower MD in the ML and ICP. BESS 1 was associated with higher FA, and BESS 3 was associated with lower MD in the same tracts in non-soccer athletes. Discussion and Conclusions: Soccer and non-soccer athletes showed unique relationships between sway and WMO, suggesting that sportspecific exposures are partly responsible for changes in neurological structure and accompanying postural control performance and should be considered when evaluating postural control after injury. [ABSTRACT FROM AUTHOR]

Purpose: The aim of the study was to assess the influence of menstrual cycle phase on injury incidence, severity, and type in elite female professional footballers over three seasons. Methods: Time-loss injuries and menstrual cycle data were prospectively recorded for 26 elite female football players across three seasons. The menstrual cycle was categorized into four phases using a standardized model: menstruation (phase 1; P1), remainder of follicular phase (phase 2; P2), early luteal (phase 3; P3), and premenstrual phase (phase 4; P4). Injury incidence rates (IIR) and ratios (IIRR) were calculated for overall injuries, injury severity, type, contact vs noncontact, and game/training. Results: A total of 593 cycles across 13,390 d were tracked during the study, and 74 injuries from 26 players were eligible for analysis. When comparing IIR between phases (reference: P1), overall injury rates were highest in P4 (IIRR, 2.30 (95% confidence interval, 0.99-5.34; P = 0.05)). When examining rates by injury severity and type, IIR values were also highest in P4 for ≤7 d' time-loss (4.40 (0.93-20.76; P = 0.06)), muscle-specific (6.07 (1.34-27.43; P = 0.02)), and noncontact (3.05 (1.10-8.50; P = 0.03)) injuries. Muscle-specific (IIRR P3/P1, 5.07 (1.16-22.07; P = 0.03)) and ≤7 d' time-loss (4.47 (1.01-19.68; P = 0.05)) injury risk was also significantly higher in P3. Muscle injuries were the most prevalent subtype (n = 41). No anterior cruciate ligament injuries were recorded across the monitoring period. Conclusions: Injury risk was significantly elevated during the luteal phase of the menstrual cycle (P3 and P4) among elite female professional footballers. Further research is urgently needed to better understand the influence of the menstrual cycle on injury risk and to develop interventions to mitigate risk. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study is to evaluate the concordance of predicted maturity status classifications (pre-, circa-, or post-peak height velocity (PHV)) relative to observed age at PHV in youth soccer players. Methods: Longitudinal height records for 124 male soccer players were extracted from academy records spanning the 2000 to 2022 seasons. Age at PHV for each player was estimated with the Superimposition by Translation and Rotation model. Players were classified as pre-, circa-, or post-PHV using both ±1- and ±0.5-yr criteria to define the circa-PHV interval. Maturity status was estimated with several prediction protocols: maturity offset (Mirwald, Moore-1, Moore-2), maturity ratio (Fransen), and percentage of predicted adult height (PAH%) using the Khamis-Roche and Tanner-Whitehouse 2 equations using several bands: 85% to 96%, 88% to 96%, 88% to 93%, and 90% to 93% for the circa-PHV interval, and visual evaluation of individual growth curves alone or with PAH% based on Khamis-Roche and Tanner-Whitehouse 2. Concordance of maturity status classifications based on complete growth curves and predicted estimates of maturity status was addressed with percentage agreement and Cohen's kappa. Results: Visual evaluation of the growth curves had the highest concordance (≈80%) with maturity status classifications (pre-, circa-, post-PHV) based on longitudinal data for individual players. Predicted maturity offset with the Mirwald, Moore-1, and Fransen equations misclassified about one-third to one-half of the players, whereas concordance based on PAH% varied with the band used, but not with the method of height prediction. Conclusions: Visual assessment of the individual growth curves by an experienced assessor provides an accurate estimate of maturity status relative to PHV. Maturity offset prediction equations misclassify the majority of players, whereas PAH% provides a reasonably valid alternative. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to examine the recovery kinetics (i.e., time-dependent changes) of performance-related variables between two 120-min male football games performed 3 d apart with and without carbohydrate supplementation. Methods: Twenty male players (20 ± 1 yr; body fat, 14.9% ± 5.1%; maximal oxygen consumption, 59.4 ± 3.7 mL⋅kg-1⋅min-1) participated in two 120-min football games (G1, G2) according to a randomized, two-trial, repeated-measures, crossover, double-blind design. Participants received carbohydrate/placebo supplements during recovery between games. Field activity was monitored during the games. Performance testing and blood sampling were performed before and at 90 and 120 min of each game. Muscle biopsies were collected at baseline and at 90 and 120 min of G1 and pre-G2. Results: Compared with G1, G2 was associated with reduced total distance (10,870 vs 10,685 m during 90 min and 3327 vs 3089 m during extra 30 min; P = 0.007-0.038), average (6.7 vs 6.2 km/h during extra 30-min game-play; P = 0.007) and maximal speed (32.2 vs 30.2 km/h during 90 min and 29.0 vs 27.9 km/h during extra 30 min; P < 0.05), accelerations/decelerations (P < 0.05), and mean heart rate (P < 0.05). Repeated sprint ability (P < 0.001), jumping (P < 0.05), and strength (P < 0.001) performance were compromised before and during G2. Muscle glycogen was not restored at G2 baseline (P = 0.005). Extended game-play reduced lymphocyte, erythrocyte counts, hematocrit, hemoglobin, reduced glutathione (P < 0.05) and increased delayed onset of muscle soreness, creatine kinase activity, blood glycerol, ammonia, and protein carbonyls (P < 0.05) before and during G2. Pax7+ (P = 0.004) and MyoD+ cells (P = 0.019) increased at baseline G2. Carbohydrate supplementation restored performance and glycogen, reduced glycerol and delayed onset of muscle soreness responses, and increased leukocyte counts and Pax7+ and MyoD+ cells. Conclusions: Results suggest that extended football games induce a prolonged recovery of performance, which may be facilitated by carbohydrate supplementation during a congested game fixture. [ABSTRACT FROM AUTHOR]

This 14-week, 2-phase study aimed to determine the relative effects of 1 day or 2 days of volume-matched plyometric training on athletic performance (10- and 40-m sprints, change of direction [COD], and vertical jump [VJ]) in male soccer players (phase 1). The objective of phase 2 was to determine the relative effects of higher- and lower-volume plyometric training protocols in maintaining any previously attained increases in athletic performance from phase 1. A randomized parallel-group trial design was utilized. In phase 1, subjects (n = 24; mean age: 19.5 ± 1.2 years; mean height: 179.7 ± 7.1 cm; mean weight: 69.8 ± 6.9 kg) were randomly allocated to 1 of 2 groups to receive either 1 day or 2 days of volume- and intensity-matched plyometric training for a 7-week period. For the second 7-week period (phase 2), half of each group was randomized into either a lower-volume or higher-volume plyometric training group. In phase 1, both the 1-day group and the 2-day group attained comparably significant (p < 0.001) increases in performance in all fitness tests ranging from effect sizes (ESs) (d) of 0.4 (95% confidence interval: 0.11 to 0.70) for 10-m sprint to 1.51 (0.42-2.60) for VJ. There were no significant differences between the performance increases in the 2 groups. In phase 2, neither group increased or decreased performance, maintaining all previously attained increases with only trivial ESs observed (-0.02 [-0.58 to 0.53] to 0.11 [-0.38 to 0.61]). Increases in 10-and 40-m sprint speed, COD speed, and VJ height can be achieved and maintained with as little as 1 plyometric training session per week. Sessions can include 120 jumps to induce increases of the reported magnitudes, with 60 jumps to maintain these increases thereafter, in male soccer players. [ABSTRACT FROM AUTHOR]

The aim of this study was to quantify and compare weekly external load and within-week load variation of reserve team players (RES) in a 1-game week microcycle to first team players (FT) in a 2-game week microcycle within the same professional soccer club. External load data were collected between 2017 and 2020 for the following parameters: duration, total distance (TD), total high-speed distance (THSD; >19.8 km·h-1), high-speed distance (HSD; 19.8-25.2 km·h-1), sprint distance (SD; >25.2 km·h-1), number of sprints (number of efforts >25.2 km·h-1), number of high-speed efforts (number of HS efforts >19.8 km·h-1), meters per minute (m·min-1), and high-speed meters per minute (HS m·min-1). First team players were subcategorized into starters (ST) and nonstarters (NST). Intergroup differences in cumulative weekly load and weekly load patterns were statistically analyzed, whereas training monotony (TM) was quantified to assess intragroup, within-week, load variation. Reserve team players showed similar weekly loads to ST, apart from significant differences (p < 0.005) in duration (8%), TD (21%), and HS efforts (16%). Similar to ST, RES showed greater values than NST (p < 0.0005) for duration (10%), TD (9%), THSD (30%), HSD (26%), SD (45%), sprints (40%), and HS efforts (22%). Weekly patterns in RES were different from ST and NST (p < 0.05). Training monotony was highest for NST for all parameters, apart from the number of sprints. Reserve team players need to be prepared to cope with cumulative weekly loads and the lack of recovery between games that ST face. However, when RES become NST, effective loading strategies need to be designed within the limits of 2-game week microcycles to ensure continuous development. [ABSTRACT FROM AUTHOR]

This study aimed, first, to verify if physical parameters were different between players' positions during official matches in English professional football, and second, if the game location (H and A) or results (W, L, D) affected players' physical performance. Twenty-five male professional football players of the same team were included in this data analysis (age = 27 ± 9 years) during the 2022-23 season. Players were divided into positions: center backs, wide backs, center midfielders, attacking midfielders, and strikers. The external load parameters were distance covered, high-speed running (HSR), sprinting distance, accelerations, decelerations, and high metabolic load distance (HMLD, meters > 25.5 w·kg -1) that were monitored using global navigation satellite systems Apex (STATSports). Linear mixed models' analysis for positions reported a significant difference in total distance (p = 0.011), HSR (p < 0.001), sprinting distance (p < 0.001), accelerations (p = 0.003), decelerations (p = 0.002), and HMLD (p < 0.001). Centre backs showed the lowest physical performance in the metrics analyzed, whereas players in the other positions frequently displayed a similar physical performance. Regarding locations and results, differences were only found between locations for decelerations (p = 0.041) and between results for HMLD (p = 0.010). In conclusion, physical performance was influenced by players' positions, whereas game location or results seem to not affect physical performance during official competitions. Consequently, practitioners can physically prepare their players independently from the location of the match or of the possible game results, whereas specific positional training is requested to optimally prepare their players. [ABSTRACT FROM AUTHOR]

and sub-elite Gaelic football players. Global Positioning System devices were used to record the match-play running performance of sub-elite and elite players during the 2018 and 2019 seasons, respectively. In total, 783 samples were collected from 31 sub-elite and 30 elite players, from 1 elite and 1 sub-elite team. Comparisons were made on a team and positional level. Statistical significance was accepted at p ≤ 0.05. Significant positional differences were present between all positions with varying effect sizes (ESs) and p-values. Effect size was used to determine the magnitude of statistical difference. On a team level, the elite covered significantly more relative distance (p = 0.021, ES = 0.007) and elicited significantly higher average speed (p = 0.023, ES = 0.007) in quarters 2, 3, and 4 than the sub-elite. The elite covered significantly more relative distance high-intensity running (17-21.9 km·h-1; p = 0.002, ES = 0.012) in quarter 3 and performed significantly more power events per minute (p = 0.006, ES = 0.009) in quarter 4. In quarter 1, the sub-elite performed significantly more power events per minute (p = 0.006, ES = 0.009), relative high-speed running (≥17 km·h-1; p = 0.011, ES = 0.009), and relative distance high-intensity running (17-21.9 km·h-1; p = 0.002, ES = 0.012). Power events were defined as the estimation of the number of events that depend on anaerobic processes. The present study indicates that elite players possess superior conditioning, ability to read match-play, pacing, and anaerobic capacity. Sub-elite teams may use the present study to inform their training to potentially improve conditioning, pacing, and anaerobic capacity. [ABSTRACT FROM AUTHOR]

The objective was to employ an integrated observational-notational record to describe collective behavior (CB) in competition matches of young soccer players from 4 teams, U-16, U-17, U-19, and U-23, playing for a professional soccer club academy. A total of 1,481 possessions were registered. Collective behavior, captured by GPS devices, was described with the variables: depth, surface area, stretch index, length, and width. In addition, from the notational analysis, the behavior depending on the area of the field (Z1,Z2, Z3, and Z4)and ball possession (POS), nonball possession (nPOS), and set pieces phases were contextualized. A 2-tailed analysis of variance was applied to compare the CB of the teams. Results show that: (a) in all ages/categories, CB varied significantly in and without the possession of the ball and was conditioned by the area of the pitch where the ball was; (b) CB showed higher values with the ball and greater variability without it; and (c) depending on the age, CB presented differences with larger effect sizes in depth and length, in and without the possession of the ball, in Z1 and Z2. Integrating positional data to the moment of play and areas of the field could help a more accurate analysis of the competition to better understand the CB evolution of young soccer players. [ABSTRACT FROM AUTHOR]

This study aimed to analyze quantitative differences in the physical demands of male elite soccer players between the first and second halves during official matches, accounting for effective playing time (the duration of play after subtracting the game interruptions) and playing positions. A total of 4,249 individual match observations of 412 outfield players competing in the Spanish first division league (LaLiga) were undertaken during the 2018-2019 season, using a computerized tracking system (TRACAB, Chyronhego, New York, NY). The players were classified into 5 positional roles: central defenders (CD), external defenders (ED), central midfielders (CM), external midfielders (EM), and forwards (F). The main results showed that in contrast to those observed when total playing time was considered, independent of playing position, there were no significant differences on high-speed running (HSR) (5.5 ± 2.4 vs. 5.5 ± 2.4 m⋅min-1)and sprint (5.3 ± 3.3 vs. 5.4 ± 3.3 m⋅min-1) distances between the first and second halves in professional soccer players when the effective playing time was considered. However, differences in match running performance at HSR and sprint distances between the first and second halves were dependent on players' playing position. Whereas ED and EM maintained HSR and sprint efforts during the second half, CD and CM significantly increased (p < 0.001) the distance covered at sprint during the second period of the match. Contrarily, F were unable to maintain their HSR (6.2 ± 2.3 vs. 5.9 ± 3.3 m⋅min-1) and sprint (7.0 ± 3.5 vs. 6.5 ± 3.4 m⋅min-1) match running performances during the second half. Such findings demonstrate that total playing time could overestimate fatigue-induced performance declines. Thus, effective playing time and playing position should be taken into account when interpreting the match running performance of professional soccer players. [ABSTRACT FROM AUTHOR]

Objectives: Hamstring strain injuries (HSI) are common among football and soccer athletes. Eccentric strength imbalance is considered a contributing factor for HSI. There is, however, a paucity of data on hamstring imbalances of soccer and American football athletes as they age and advance in skill level. High school athletes will display greater interlimb discrepancies compared with collegiate and professional athletes. In addition, soccer athletes will exhibit greater hamstring asymmetry than American football athletes. Methods: Hamstring testing was performed on soccer and American football athletes using the NordBord Hamstring Testing System (Vald Performance, Albion, Australia). Age, sex, weight, sport specialization, and sport level were recorded. Maximum hamstring forces (N), torque (N · m), and work (N · s) were measured. Hamstring imbalance (%) was calculated by dividing the absolute value of the difference in leg forces divided by their sum. One-way analysis of variance and independent sample t tests compared measurements between athlete groups. Results: A total of 631 athletes completed measurements, including 88 high school male soccer, 25 college male soccer, 23 professional male soccer, 83 high school female soccer, 28 college female soccer, 288 high school football, and 96 college football athletes. High school soccer players displayed significantly greater imbalances for torque (P = 0.03) and work (P < 0.01) than football athletes. Imbalances for maximum force (P = 0.035), torque (P = 0.018), and work (P = 0.033) were significantly higher for male soccer athletes in high school compared with college- and professional-level athletes. Female high school soccer players had significantly higher imbalance in torque (P = 0.045) and work (P = 0.001) compared with female collegiate soccer players. Football athletes did not experience significant changes in force imbalances between skill levels. Conclusions: High school soccer athletes exhibit greater hamstring imbalances than football athletes. Higher levels of play in soccer, for both male and female athletes, correlate with less hamstring asymmetry. [ABSTRACT FROM AUTHOR]

Beato, M, Wren, C, and de Keijzer, KL. The interunit reliability of global navigation satellite systems Apex (STATSports) metrics during a standardized intermittent running activity. J Strength Cond Res 38(2): e49-e55, 2024--This study aimed to evaluate the interunit reliability of global navigation satellite systems (GNSS) STATSports Apex metrics and to assess which metrics can be used by practitioners for the monitoring of short-distance intermittent running activities. Fifty-four male soccer players were enrolled (age 5 20.7 6 1.9 years, body mass 5 73.2 6 9.5 kg, and height 5 1.76 6 0.07 m) in this observational study. 10-Hz GNSS Apex (STATSports, Northern Ireland, Newry) units recorded total distance, high speed running (HSR), accelerations, decelerations, peak speed, average metabolic power, metabolic distance, dynamic stress load (DSL), relative distance, and speed intensity. The standardized intermitted running protocol used was a Yo-Yo intermittent recovery level 1. This study reported that Apex interunit analysis did not show any significant difference (delta difference and 95% confidence interval [CIs]) in total distance52.6 (22.6; 7.9) m, HSR 5 3.2 (20.2; 6.8) m, accelerations 5 0.09 (20.9; 1.1), decelerations 5 0.3 (20.4; 1.1), peak speed 5 0.02 (20.03; 0.07) m·s21, average metabolic power50.01 (20.02; 0.04)W·kg21, metabolic distance50.9 (26.2; 8.0) m, DSL52.8 (25.6; 10.7) au, relative distance 5 0.14 (20.19; 0.47) m·min21, and speed intensity 5 0.21 (20.21; 0.64) au. All metrics presented a delta d between trivial to small. The interunit intraclass correlation coefficient (ICC) was good or excellent for all metrics, with the exception of DSL, which was considered questionable. In conclusion, this study reports that all the metrics analysis in this study presents a low interunit bias and high reliability (ICC), with the exception of DSL. [ABSTRACT FROM AUTHOR]

Santos da Silva, V, Nakamura, FY, Gantois, P, Nogueira Gouveia, JN, Pen? a, J, Beato, M, and Abade, E. Effects of upper-body and lower-body conditioning activities on postactivation performance enhancement during sprinting and jumping tasks in female soccer players. J Strength Cond Res 38(2): 342-349, 2024--This study aimed to investigate the postactivation performance enhancement (PAPE) effects of "specific" (half-back squat) and "nonspecific" (bench press) conditioning activities on sprinting and jumping performances in female soccer players. Fourteen players (mean6SD: age522.364.0 years; body mass560.267.8 kg; height 5 164.1 6 4.2 cm) competing at national level (first League) participated in this within-subject crossover study. The players performed a warm-up protocol including 3 sets of 3 repetitions of half-back-squat or bench press exercises at 90% 1RM or a warmup protocol without lifting weights (i.e., control condition). Forty-meter shuttle sprints (20 + 20 m with change of direction [COD-180°]), countermovement jump (CMJ), and horizontal jump (HJ) performances were recorded 6 minutes after the conditioning activities protocols or the control condition. Nonsignificant large positive effects were found for the HJ after the half-back-squat (ES 51.68; p.0.05) and bench press (ES51.68; p.0.05) protocols. Although nonsignificant, HJ changes (D50.07 m) were greater than the smallest worthwhile change (0.02 m) and standard error of measurement (0.03 m) after both conditioning activities. Moreover, no significant changes were found for sprint and CMJ performance after neither half-back-squat nor bench press protocols (p. 0.05). In conclusion, both specific and nonspecific conditioning activities using heavy loads (i.e., 90% 1RM) may be suitable to enhance individual HJ. Finally, both conditioning activities are potentially ineffective for increasing sprint and CMJ performance in the context of this study. [ABSTRACT FROM AUTHOR]

McAuley, ABT, Hughes, DC, Tsaprouni, LG, Varley, I, Suraci, B, Bradley, B, Baker, J, Herbert, AJ, and Kelly, AL. Genetic associations with acceleration, change of direction, jump height, and speed in English academy football players. J Strength Cond Res 38(2): 350-359, 2024--High-intensity movements and explosive actions are commonly assessed during athlete development in football (soccer). Although many environmental factors underpin these power-orientated traits, research suggests that there is also a sizeable genetic component. Therefore, this study examined the association of 22 single-nucleotide polymorphisms (SNPs) with acceleration, change of direction, jump height, and speed in academy football players. One hundred and forty-nine, male, under-12 to under-23 football players from 4 English academies were examined. Subjects performed 5-, 10-, 20-, and 30-m sprints, countermovement jumps (CMJs), and the 5-0-5 agility test. Simple linear regression was used to analyze individual SNP associations, whereas both unweighted and weighted total genotype scores (TGS; TWGS) were computed to measure the combined influence of all SNPs. To control for multiple testing, a Benjamini-Hochberg false discovery rate of 0.05 was applied to all genotype model comparisons. In isolation, the GALNT13 (rs10196189)Gallele and IL6 (rs1800795) G/G genotype were associated with faster (;4%) 5-, 10-, and 20-m sprints and higher (;16%) CMJs, respectively (p, 0.001). Furthermore, the TGS and TWGS significantly correlated with all performance assessments, explaining between 6 and 33% of the variance (p, 0.001). This study demonstrates that some genetic variants are associated with power-orientated phenotypes in youth football players and may add value toward a future polygenic profile of physical performance. [ABSTRACT FROM AUTHOR]

Objective: Exposure to repetitive sports-related concussions or (sub)concussive head trauma may lead to chronic traumatic encephalopathy (CTE). Which impact (heading or concussion) poses the greatest risk of CTE development in soccer players? Design: Narrative review. Setting: Teaching hospital and University of Applied sciences. Patients: A literature search (PubMed) was conducted for neuropathologic studies in the period 2005-December 2022, investigating soccer players with dementia and a CTE diagnosis, limited to English language publications. 210 papers were selected for final inclusion, of which 7 papers described 14 soccer players. Assessment: Magnetic resonance imaging studies in soccer players show that lifetime estimates of heading numbers are inversely correlated with cortical thickness, grey matter volume, and density of the anterior temporal cortex. Using diffusion tensor imaging–magnetic resonance imaging, higher frequency of headings—particularly with rotational accelerations—are associated with impaired white matter integrity. Serum neurofilament light protein is elevated after heading. Main Outcome Measures: Chronic traumatic encephalopathy pathology, history of concussion, heading frequency. Results: In 10 of 14 soccer players, CTE was the primary diagnosis. In 4 cases, other dementia types formed the primary diagnosis and CTE pathology was a concomitant finding. Remarkably, 6 of the 14 cases had no history of concussion, suggesting that frequent heading may be a risk for CTE in patients without symptomatic concussion. Rule changes in heading duels, management of concussion during the game, and limiting the number of high force headers during training are discussed. Conclusions: Data suggest that heading frequency and concussions are associated with higher risk of developing CTE in (retired) soccer players. However based on this review of only 14 players, questions persist as to whether or not heading is a risk factor for CTE or long-term cognitive decline. [ABSTRACT FROM AUTHOR]

Several laboratory and field testing protocols have been developed attempting to simulate the activity pattern and physiological demands of soccer. In the present systematic review, we aimed to analyze and discuss the appropriateness, strengths, and limitations of soccer-specific simulated tests. A systematic review of the literature was conducted based on the PRISMA guidelines. Studies conducted in soccer, simulated soccer match tests, and validated simulation protocols performed on-the-field or on a treadmill were considered. No sex restriction was applied, and age .18 years (i.e., adults) was considered. At least 1 outcome measure (e.g., neuromuscular performance, external load, internal load, or psychometric state) of post-simulated-match test or protocol had to be reported. Within the 14 studies included, the average methodological quality of the included articles was 0.61 6 0.09 (mean 6 SD) of 1. Overall, 9 validated protocols were identified. In the protocols, only amateur, university, or semiprofessional soccer players were analyzed. Only one study evaluated female soccer players. None of the studies evaluated the effect on performance over the 2-3 days after the protocol. Accelerations and decelerations, and changes in direction typically present in a game have not been clearly described in any protocol. Future research should address this issue and validate soccer-specific protocols in women. [ABSTRACT FROM AUTHOR]

The aim of this study was to explore the changes in physical performance by playing position throughout professional soccer match-play. Global Positioning Systems were used for the collection of external load measures during 35 matches. Each match was divided into 15-minute periods. Physical performance varied according to the period in distance covered (F 5 25.69; p, 0.001; partial eta-squared [hp2] 5 0.11), sprinting distance (SPD, F 5 4.35; p, 0.001; hp2 5 0.02), sprinting actions (SPAs, F 5 5.19; p, 0.001), high-intensity accelerations (Acc+3, F 5 2.18; p 5 0.05; hp2 5 0.01), high-intensity decelerations (Dec+3, F 5 4.51; p, 0.001; hp2 5 0.02), and high-metabolic load distance (HMLD, F 5 5.59; p, 0.001; hp2 5 0.03). The period with the greatest mean physical performance was usually from the first half of the matches: 0-15 minutes (distance, Acc+3, and Dec+3) and 30-45 minutes (HMLD, SPA, and SPD). However, the lowest mean physical performance compared with the rest of 15-minute periods was observed in the 60-75-minute period (distance, HMLD, Acc+3, and Dec+3), except for SPA and SPD (15-30 minutes and 75-90 minutes). Overall, no significant differences (p. 0.05) were observed in the physical performance between the extratime periods. In addition, the playing position had a significant effect on all performance variables (F 5 39.99-133.29; p, 0.001; hp2 5 0.14-0.34). Central defenders showed the lowest physical performance throughout the periods of match-play, whereas wide midfielders showed the greatest physical performance in all variables, except for distance covered, in which midfielders had the greatest performance. In conclusion, there were changes in physical performance during the matches depending on the period of match-play and playing position. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the relationship between agility performance and cognitive functions measured under laboratory conditions among elite young soccer players. Twenty-five, elite, young, male soccer players (12.3 6 0.4 years, 155.4 6 7.6 cm, 42.6 6 6.9 kg) completed a battery of field tests, including 5-, 10-, 20-m sprints, change of direction speed (CODS), standing long jump, and an agility test based on a human stimulus. Subjects also completed choice reaction (RT, S3) and reactive stress tolerance (DT, S1) tests on the Vienna Test System. There was a moderate significant relationship (p, 0.05) found between mean reaction time and mean motor time during the choice reaction task and decision time in the agility test. Decision time also showed a large significant correlation (p, 0.05) with total time in the agility test. No significant correlation was found between total time in the agility test and variables measured during RT and DT tests. No significant correlations were found between agility test results and results from straight line sprints, CODS, and standing long jump tests. The results of this study suggest that choice reaction time is related to decision-making speed during the agility task used in this study and can have an indirect effect on agility performance in elite young soccer players. Further studies assessing the relationship between different cognitive functions and agility performance in different sports and age categories could help in the identification of determinant cognitive functions in perceptual and decision-making factors of agility. [ABSTRACT FROM AUTHOR]

Brown, GA, Massard, T, Wignell, T, McCall, A, and Duffield, R. Monitoring training load and wellness of female footballers transitioning between club and national teams. J Strength Cond Res 37(11): 2235-2240, 2023--This study described the change in training and match internal loads, plus perceptual wellness during the transition between club and national teams (NTs) for female international footballers (soccer). Session count, session rating of perceived exertion (s-RPE), and perceptual wellness data were collected from 42 players from 1 NT between 2019 and 2021 for 7 NT tournaments. Data were collated into 7-day (1 week) microcycles to compare the 2 weeks before the first week of NT (transition in: NT-2, NT-1, NT1); and separately from the final NT week to the next 2 weeks in clubs (transition out: NTFinal, NT+1, NT+2). Data were analyzed using linear mixed-models, with session count, s-RPE or wellness as the outcome variable, week as the fixed effect, player name, and tournament as random effects. Tukey's adjusted post-hoc comparisons and Cohen's d effect sizes (ES) were compared between weeks. Significance level was set at p, 0.05. During the transition into NT, training and total session counts increased (p, 0.0001, ES. 0.67), training s-RPE increased (p50.012, ES50.35), whereas match count and s-RPE decreased (p,0.05, ES,20.34). During the transition out of NT, there were decreases in training session count (p, 0.05, ES,20.37), match count, and total session count (p, 0.0001, ES ,20.86), and match and total s-RPE (p,0.0001, ES,20.63). Perceived wellness was not significantly different throughout (p. 0.05, ES 5 20.34 to 0.35). Thus, training and match exposures differ between club and NTs, demonstrating these unique transitional periods require simple and effective load monitoring to inform training and recovery prescription when changing between club and NTs. [ABSTRACT FROM AUTHOR]

The purposes of this study were to reduce dimensionality of external training load variables and examine how the selected variables varied within microcycle in elite North American soccer players. Data were collected from 18 players during 2018-2020 in-seasons. Microcycle was categorized as 1, 2, 3, 4, 5 days before match day (MD-1, MD-2, MD-3, MD-4, and MD-5, respectively). Training load variables included total distance, average speed, maximum velocity, high-speed running distance (HSR), average HSR, HSR efforts, average HSR efforts, sprint distance, average sprint distance, sprint efforts, average sprint efforts, total PlayerLoad, and average PlayerLoad. The first principal component (PC) can explain 66.0% of the variances and be represented by "high-speed load" (e.g., HSR and sprint-related variables) with the second PC relating to "volume" (e.g., total distance and PlayerLoad) accounting for 17.9% of the variance. Average sprint distance and total distance were selected for further analysis. Average sprint distance was significantly higher at MD- 3 than at MD-2 (p50.01, mean difference50.36m•minute-1, 95% confidence intervals [CIs]50.07-0.65m•minute-1) and MD-4 (p 5 0.012, mean difference 5 0.26 m•minute-1, 95% CIs 5 0.10-0.41 m•minute-1). Total distance was significantly higher at MD-3 than at MD-1 (p,0.001, mean difference 51,465 m, 95% CIs51,003-1926 m), and MD-2 (p,0.001, mean difference 5 941 m, 95% CIs 5 523-1,360 m). Principal component analysis may simplify reporting process of external training loads. Practitioners may need to choose "volume" and "high-speed load" variables. Elite North American Soccer players may accumulate higher average sprint distance at MD-3 than at other training days. [ABSTRACT FROM AUTHOR]

Modric, T, Esco, M, Perkovic, S, Basic, Z, Versic, S, Morgans, R, and Sekulic, D. Artificial turf increases the physical demand of soccer by heightening match running performance compared with natural grass. J Strength Cond Res 37(11): 2222-2228, 2023--This study aimed to determine differences in match running performance (MRP) of elite soccer players (n 5 31) during matches played on artificial turf (AT) and natural grass (NG). The players' MRP (AT; 131 observations, NG; 135 observations) were collected during official matches (n 5 32) using global positioning system and classified according to their playing positions as central defenders, central midfielders, fullbacks, forwards, and wingers. The MRP variables included total distance covered (TD), low-intensity running (LIR), moderate-intensity running (MIR), high-intensity running (HIR), total (Tacc) and high-intensity accelerations (Hacc), and total (Tdec) and high-intensity decelerations (Hdec). The influence of match outcome, location, and opponent quality was controlled for as contextual factors. Playing matches on AT resulted in (a) increased TD (Cohen's d (d)50.55, 0.61, and 0.28, respectively), MIR (d 5 0.91, 0.79, and 0.49, respectively), and HIR (d 5 0.67, 0.44, and 0.38, respectively) for central defenders, central midfielders, fullbacks; (b) increased Tacc (d 5 0.38, 0.37, and 0.4, respectively) and Tdec (d 5 0.31, 0.34, and 0.31, respectively) for central defenders, central midfielders, and wingers; and (c) decreased Hdec (d521.5) for forwards. These results show that playing on AT is more physically demanding for defensive and midfield players than playing on NG. Soccer coaches should consider implementing preparatory strategies that mitigate the increased demands of playing on AT for these players, especially before a competitive period when transitions between pitch surfaces routinely occur. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the effects of a 4-week detraining period on the neuromuscular performance of highly trained soccer players. Pre and post detraining, 18 adult soccer players (age: 27 64.9 years; height: 180.267.1 cm; body mass [BM]: 78.967.6 kg) performed vertical jumps, 20-m linear sprints, curve sprint and change of direction speed tests, and a progressive loading test in the half-squat exercise with loads corresponding to 50, 100, and 150% of the players' BM to assess the peak-force (PF), mean power (MP), and strength-deficit (SDef). Pre and post differences in the variables of interest were analyzed using paired t-tests and effect sizes (ES). No significant changes were detected for vertical jumping height and sprint times. Higher PF at 50 and 100% BM and lower SDef were shown when comparing pre- and post-assessments (ES = 0.66, 0.68, 0.55; p = 0.018, 0.016, and 0.046, respectively). The MP at 50 and 100% BM increased significantly after the detraining phase (ES = 0.56, 0.82; p = 0.049 and 0.007, respectively). The results indicate that these athletes were able to maintain and achieve satisfactory levels of performance after a short period of training cessation. Interestingly, some strength- and power-derived parameters improved significantly after short-term detraining, which may have important implications for training programs aimed at maximizing speed and power performance. It is recommended that coaches test their players not only at the beginning but also at the end of the season, to better evaluate variations in performance and thus create more efficient and tailored training strategies. [ABSTRACT FROM AUTHOR]

Head impacts during blind football are common and have high injury rates; however, their characteristics and impact are still underreported. We compared head impact characteristics in blind football players with and without falls on all 18 official blind football match videos from the Tokyo 2020 Paralympic games. The rate of head impacts with falls was significantly higher in the preliminary phase, offense phase, and during dribbling. Significant differences in the region of the head impacted were also observed among the impact subjects/objects. The findings in this study would contribute to the development of injury prevention measures to minimize head injuries from head impact in blind football. [ABSTRACT FROM AUTHOR]

This study aimed to investigate if external training load metrics differ between training days and match day (MD) during a period of fixture congestion and to verify if external load metrics vary based on playing positions. Training and MD data were collected in a part of the competition phase of the 2020-2021 season (6 weeks) in the English Football League 2 (N = 20 players, mean ± SDs: age = 24.4 ± 4.7 years). Global Navigation Satellite System units (Catapult S7 Vector 10 Hz) were used to monitor external load metrics. The metrics were duration of training, total distance (TD), high-speed running distance (HSR), sprinting distance, relative intensity (m/min), total accelerations (TotAcc) (>3 m⋅s-2), and total decelerations (TotDec) (<-3 m⋅s-2). This study found that duration, TD, relative intensity, HSR distance, sprint distance, TotAcc, and TotDec were different (p < 0.001, d = small to moderate) between MD and match day minus two (MD-2) or match day minus one (MD-1); however, during match day minus four (MD-4), only relative intensity was significantly lower (p < 0.001) compared with MD output. Therefore, MD-4 was the most demanding training session of the week (after the MD), and during MD-2 and MD-1, coaches decreased players' load to favor players' readiness. Moreover, this study found that MD and MD-1 resulted in statistically different values across several metrics between different playing positions (defenders < midfielders and strikers), whereas metrics in MD-4 and MD-2 were not statistically different, which highlights that in these sessions, players have similar external loads independently from their playing positions. [ABSTRACT FROM AUTHOR]

The aim of this narrative review is to evaluate the presented literature on tests (aerobic, speed, changes of direction [COD], strength, power, jump, and anthropometry) of the varied components of female soccer and to draw attention to the most suitable protocols to allow practitioners to accurately track players' fitness status. The 2 most common field tests used to assess aerobic fitness are the Yo-Yo intermittent test (level 1 and level 2) and the 30-15 intermittent fitness test because of an ability to measure multiple players at once with a soccer-specific intermittent profile. The sprinting performance can be assessed on distances of <30 m; however, longer distances (e.g., 40 m) allow for achieving peak speed (flying sprint test), which can be assessed using global navigation satellite system. Changes-of-direction capacity has been found to be an important component of players testing and training programs, although there is no "gold standard" to assess COD or repeated sprint ability performance in female players. Lower-limb power can be assessed using jump tests that can use force platforms, jump mats, and optoelectronic devices, while maintaining a good reliability. Several in-direct tests are currently available for assessing anthropometry parameters, such as skinfold thickness, hydrodensitometry, and ultrasound. However, dual-energy x-ray absorptiometry is the most valid and reliable method for assessing body composition in team sport athletes, with the addition of bone health that is a key measure in female athletes. In conclusion, the evidence reported in this review will be able to aid practitioners, coaches, and researchers to decide which tests meet the requirements of their environment. [ABSTRACT FROM AUTHOR]

In the last decade, monitoring physiological and match-related demands in soccer has become an increasingly common practice in sports sciences. One of the great challenges during monitoring process is the identification of key indicators that permit to generalize evidence and sustain decision-making process during training prescription. Actually, one of the major debates in the scientific community and among practitioners is the identification of the "intensity" concept. Defining a given training session or exercise based on "intensity" is difficult due to the fact that a huge amount of indicators are available (related both to the performed activities and to the athletes' psychophysiological responses). These indicators can lead to specific outcomes with different interpretations. The current narrative review aims to discuss the different measures approaches used in soccer to describe the intensity for both internal and external demands. In addition, a second purpose of this review is to propose general recommendations for combining intensity indicators with the aim of defining an overall intensity score of a training session or drill. [ABSTRACT FROM AUTHOR]

Postactivation performance enhancement activities may be relevant warm-up strategies aiming to improve subsequent physical performance. The purpose of the current study was to investigate the effects of adding barbell deadlift or hex-bar deadlift exercises to current warm-up routines on running and jumping performances in football players. Ten highly trained male football players participated in the study during the competitive phase of the season. All players performed 3 protocols in the same week: a standard warm-up that included players' regular routines and 2 other protocols with the addition of barbell or hex-bar deadlift, after the end of the warm-up (3 sets of 3 reps, progressing set by set from 60% to 85% repetition maximum). All protocols had the same time interval between pretest (immediately after the warm-up) and posttest (15 minutes after the warm-up). Vertical jumping (countermovement jump [CMJ]; Abalakov jump [AJ]) and running performances (505 test) were impaired 15 minutes after the standard warm-up (CMJ: -6.7 ± 4.2%; AJ: -8.1 ± 8.4%; and 505 time: 1.4 ± 2.5%). For warm-up with the addition of barbell deadlift, vertical jump increased by 4.3 ± 5.6% (Cohen's dunb: 0.23 [0.02-0.47]) and 505 time decreased by -5.9 ± 3.6% (Cohen's dunb: 0.97 [-1.68 to -0.43]). The warm-up with hex-bar deadlift led to trivial changes for CMJ and AJ, but 505 time decrease by -2.7 ± 2.6% (Cohen's dunb: -0.53 [-1.01 to -0.13]). The deadlift exercise can be added to warm-up routines to maintain or even enhance acute physical performance. However, coaches and practitioners should be aware that performance enhancements resultant from deadlift may vary according to individual physical profiles. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Changes after a conventional (CON) vs. alternative (ALT) therapy program on physical, psychological, and injury-related or pain-related parameters in soccer players with patellar tendinopathy (PT) during return to competition were examined. Thirty-four male youth soccer players (15-16 years) with PT were randomly assigned to a CON (n = 18) or ALT (n = 16) program. The ALT program consisted of 60 minutes of balance training, eccentric and isometric exercises, static stretching, and a dual-task progression. The CON program consisted of 30 minutes of eccentric and isometric exercises and static stretching. Both programs were conducted until painlessness was reported during full training load. Assessments of muscle power (drop jump, jump and reach), change of direction speed (CODS) (acyclic sprint), speed (tapping, 30-m linear sprint), endurance (Yo-Yo intermittent recovery test level-1), the Achievement Motives Scale Sport, and injury-related or pain-related correlates were performed immediately, 6 weeks, 16 weeks, and 20 weeks after the respective therapy program. Players in the ALT group required a shorter program duration (ALT: 47.1 ± 15.6 days, CON: 58.2 ± 24.6 days) and achieved the same (muscle power, speed, endurance) or greater (CODS) improvements in physical performances, the same enhancements in psychological measures (achievement motives), and better values for injury-related or pain-related correlates (injury incidence, pain-related training interruptions). Results indicate that both programs effectively improve relevant outcome parameters in players with PT. The ALT therapy is more time efficient than the CON therapy. Therapists should consider this multimodal training program for effective treatment of athletes to shorten their return to competition time and minimize the risk of secondary injuries. [ABSTRACT FROM AUTHOR]

The present study was intended to i) investigate the relationship between metabolic power average (MPA), acceleration (AcZ) and deceleration (DcZ) zones, and their differences (Δ) on 3 load levels with noncontact injuries in professional players throughout a full soccer season and ii) to analyze the injury risk associated between high-load versus low-load levels for each of the aforementioned parameters with odds ratios (OR) and relative risk (RR), respectively. Twenty-one professional soccer players (age = 28.3 ± 3.9 years) were monitored during a full season (48 weeks) through global positioning system (GPS). A relationship between MPA and accelerometer-based GPS, mainly in explosive actions (i.e., AcZs and DcZs), was found. A higher incidence of injuries in the high-load weeks compared with the low-load weeks were reported (mainly in MPA, AcZ1, AcZ2, and DcZ3 variables). Moreover, significant means of OR (mean = 4.3) and RR (mean = 2.6) of noncontact injuries were established in intense periods with higher metabolic load (i.e., power accelerations, AcZ1, x² = 0.022). Our results may be useful for coaches, sports scientists, and researchers regarding the optimization of the athletes' performance, as well as providing insights about the impact of intense exercise. [ABSTRACT FROM AUTHOR]

Supplemental Digital Content is Available in the Text. Objective: We performed a systematic review and meta-analysis to evaluate the injury burden and the related economic cost in European professional male football players. Data Sources: Multiple database research was performed up to August 5, 2022 (PubMed, EMbase, Scopus, Cochrane Library), including only studies that reported severity in the number of days of absence for each injury, incidence reported in the number of injuries/1000 hours, or reported number of injuries and exposure time and adult male football players, professionals from European clubs. Two reviewers extracted data and assessed paper quality with the Strengthening the Reporting of Observational Studies in Epidemiology statement and the Newcastle–Ottawa Scale. Main Results: Twenty-two studies have reported incidence, severity, and burden of injuries in professional football. The highest injury burden was found for ligament–joint injuries (37.9 days/1000 hours; 222 397 €/1000 hours) and for muscle injuries (34.7 days/1000 hours; 203 620 €/1000 hours). Injury locations with high burden were knee injuries (34.8 days/1000 hours; 20 4206 €/1000 hours)—mainly anterior cruciate ligament injuries (14.4 days/1000 hours; 84 499 €/1000 h)–followed by thigh injuries (25.0 days/1000 hours; 146 700 €/1000 hours), hamstrings injuries (15.4 days/1000 hours; 90 367 €/1000 hours), hip-and-groin injuries (16.1 days/1000 hours; 94 475 €/1000 hours), primarily adductor muscles injuries (9.4 days/1000 hours; 55 159€/1000 hours), and ankle injuries (13.1 days/1000 h; 76 871 €/1000 hours) with ankle sprains (7.4 days/1000 hours; 43 423 €/1000 hours). Conclusions: Being exposed to injury risk has serious consequences for individual and club performance and economy. This review identified the most relevant targets in injury management, compared their injury data with reference values, and provided economic evidence when trying to gain buy-in from the key decision makers. [ABSTRACT FROM AUTHOR]

Football performance involves several physical abilities that range in aerobic, anaerobic, and neuromuscular domains; however, little is known about their interplay in profiling individual physical attributes. This study aimed to profile physical performance in youth football players according to their training status. One hundred seven young male soccer players (age 13.5 ± 1.4 years; height 168 ± 7 cm; body mass 57.4 ± 9.6 kg; and body mass index 20.2 ± 2.1 kg·m-2) volunteered for this study. Players' physical performance was assessed with football-relevant field tests for sprinting (10 m sprint), vertical jump (countermovement jump), intermittent high-intensity endurance (Yo-Yo Intermittent Recovery Test Level 1, YYIRT1), and repeated sprint ability (RSA). The training status was assumed as testosterone and cortisol saliva concentrations; biological maturation was estimated using the Pubertal Development Scale. Exploratory factor analysis (EFA) revealed 3 main variables depicting anthropometric (D1, 24.9%), physical performance (D2, 18.8%), and training status (D3, 13.3%), accounting for 57.0% of total variance altogether. The level of significance was set at p ≤ 0.05. The RSA and YYIRT1 performances were largely associated with D2, suggesting the relevance of endurance in youth football. This study revealed that for youth football players, a 3-component model should be considered to evaluate youth soccer players. The EFA approach may help to disclose interindividual differences useful to talent identification and selection. [ABSTRACT FROM AUTHOR]

Soccer is a physically demanding sport within the National Collegiate Athletic Association and continuously increases in popularity. To ensure athletes are adequately prepared for weekly physical stressors, coaches can use global positioning system technology to monitor external workloads and exercise intensity. These data can subsequently help coaches and practitioners better implement individualized training programs to ensure athletes are properly balancing the overreaching and overtraining paradigm. Therefore, the purpose of this observational study was to retrospectively analyze 3 consecutive seasons of external workload (total and high intensity distance) and injury data, which were derived from all training sessions and matches in 46 Division-I collegiate male soccer players. A coach's interpretation sought to provide practical insight into the functionality behind load management and how it prepares athletes for the physical stressors placed on them throughout a season. Two separate 3 × 3 repeated measures ANOVAs were conducted to determine differences between total distance and distance at high-intensity with an alpha level set at 0.05. Total distance between preseason and in-season (p = 0.003), acute high-intensity distance (p < 0.001), and chronic high-intensity distance (p < 0.001) yielded significant differences. These results conclude the demands of each athlete change weekly and between seasons. It is recommended that sport coaches and practitioners develop individualized training programs by workload monitoring while considering variables such as a team's style of play, experience, position, role within a program, training intensity, and the length of time between conditioning sessions, practices, and matches. [ABSTRACT FROM AUTHOR]

The effectiveness of high-load and plyometric exercises as conditioning activity (CA) is not well described in the level of performance enhancement and muscle-tendon properties. Therefore, this study aimed to compare the effectiveness of high-loaded back squats and body mass tuck jumps among amateur soccer players on the height of countermovement jump performed without (CMJ) and with arm swing (CMJa) and to verify the usefulness of the myotonometry in assessing the level of CA-induced fatigue. Therefore, 16 male amateur soccer players (resistance training experience: 2 ± 1 year, relative 1 repetition maximum back squat strength: 1.41 ± 0.12 kg·body mass-1) performed 3 experimental sessions to compare the acute effects of 3 sets of 3 repetitions at 85% one repetition maximum of half back squats (HL), 3 sets of 5 repetitions of tuck jump exercises (PLY), and no CA (CTRL) on CMJ and CMJa height. Moreover, the gastrocnemius medialis and Achilles tendon tone and stiffness were examined. Measurements were performed 5 minutes before CA and in the third, sixth, and ninth minutes after CA. The CMJ height significantly increased from pre-CA to post-CA in the CTRL (p = 0.005; effect size [ES] = 0.36; Δ = +3.4%) and PLY (p = 0.001; ES = 0.83; Δ = +8.8%) conditions. Moreover, post-CA jump height was significantly higher in PLY than in the HL condition (p = 0.024; ES = 0.6; Δ = +5.9%). No significant differences were found for CMJa height, tone, and stiffness of gastrocnemius medialis and Achilles tendon. The low-volume plyometric CA (i.e., 3 sets of 5 repetitions) is recommended instead of high-loaded CA (=85% one repetition maximum) for amateur athletes. In addition, it has been established that the performance improvement was independent of changes in the mechanical properties of the gastrocnemius medialis and Achilles tendon. Furthermore, it seems that the complexity of the post-CA task may affect the magnitude of the postactivation performance enhancement. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine longitudinal changes in fitness and body composition throughout athletes' 4-year collegiate soccer careers. Performance testing occurred before preseason during freshman, sophomore, junior, and senior year in 17 female Division I soccer players. Body composition was assessed through air-displacement plethysmography to determine percent body fat (%BF), fat-free mass (FFM), and body mass (BM). Maximal countermovement vertical jump height was assessed through contact mat using arm swing (CMJAS) and hands-on-hips (CMJHOH) methods to calculate power (CMJwatts/HOHwatts). Aerobic capacity (V̇o2max) and ventilatory threshold (VT) were assessed by indirect calorimetry during a maximal graded exercise test on a treadmill. Linear mixed models were used to assess changes across academic years (p < 0.05). No changes occurred in %BF, BM, V̇o2max, VT, CMJAS, or CMJwatts. A time main effect was seen for FFM (p = 0.01) with increases from freshman to senior (p = 0.02). Time main effects were observed for CMJHOH (p < 0.001) and CMJHOHwatts (p < 0.001) with increases from freshman to junior (CMJHOH,p = 0.001; CMJHOHwatts, p = 0.02) and senior (CMJHOH, p < 0.001; CMJHOHwatts, p = 0.003) as well as sophomore to senior (CMJHOH, p < 0.001; CMJHOHwatts, p = 0.02). Countermovement vertical jump with hands on hips also increased from sophomore to junior (p = 0.005). The lower FFM and power capabilities as freshmen compared with upperclassman indicate a potential limited readiness. Coaches and training staff should account for these developmental differences when entering the preseason. Adequate conditioning programs before starting a collegiate program may help build a fitness foundation and prepare freshmen athletes to compete at the same level as their upperclassmen counterparts. [ABSTRACT FROM AUTHOR]

The aims of this study were (a) to investigate the effects of a unilateral training program, compared with a control group, on a force-velocity (F-V) profile in soccer players and (b) to explore such effects on linear speed. Twenty-four soccer players, randomly assigned to a 6-week unilateral strength and ballistic jump training (UNI) (n = 12) or a control group (CON) (n = 12), performed 30-meter linear sprint test. Findings showed small-to-moderate improvements (p < 0.05) in linear speed time (g = 0.66-0.81) and in most F-V variables: maximal running velocity (V0) (g = 0.81), maximal power output (Pmax) (g = 0.49), maximal ratio of force (RFmax) (g = 0.55), optimal velocity (Vopt) (g = 0.83), and maximal speed (g = 0.84) from pre- to post-intervention in the UNI group, whereas no meaningful changes were found in the CON group. The between-group comparison indicated small to large significant changes in V0 (g = 0.95), RFmax (g = 0.48), Vopt (g = 0.95), maximal speed (g = 0.98), and linear speed time performance (g = 0.42-1.02), with the exception of the 0-5 meter distance, in favor of the UNI group. Thus, a unilateral strength and ballistic jump training program can be used to improve the F-V profile and linear speed performance of amateur soccer players. [ABSTRACT FROM AUTHOR]

This study examined the effects of an 8-week integrative neuromuscular training (INT) program, including balance, strength, plyometric, and change of direction exercises, on measures of physical fitness in youth male soccer players. Twenty-four male soccer players participated in this study. They were randomly allocated into an INT (n = 12; age = 15.7 ± 0.6 years, body height = 179.75 ± 6.54 cm, body mass = 78.20 ± 7.44 kg, maturity-offset = +2.2 ± 0.6 years) or an active control (CG, n = 12; age = 15.4 ± 0.8 years, body height = 178.4 ± 6.4 cm, body mass = 72 ± 8.3 kg, maturity-offset = +1.9 ± 0.7 years) group. Before and after training, tests to measure dynamic balance (Y-Balance test [YBT]), muscle strength (one repetition maximum [1RM]), muscle power (five jump test [FJT], single-leg hop test [SLHT], and countermovement jump [CMJ] height), linear sprint time (10 and 30-m), and change of direction with ball (CoDball) were performed. The analysis of covariance was used to test between-group differences (INT vs. CG) at posttest using baseline values as covariates. Significant, large, between-group differences at posttest were noted for the YBT (p = 0.016; d = 1.1), 1RM (p = 0.011; d = 1.2), FJT (p = 0.027; d = 1.0), SLHT (p = 0.04; d = 1.4), CMJ height (p < 0.001; d = 1.9), 10-m sprint (p < 0.01; d = 1.6), and CoDball (p < 0.05; d = 0.9) in favor of the INT group. Significant moderate-to-large pre-to-post changes were detected in the INT group for YBT, 1RM, CMJ height, SLHT, FJT, 10-m and 30-m sprint time, and CoDball test (d = 0.7 to 3.07, p < 0.05). No significant pre-to-post changes were observed in the CG (p > 0.05), except for 10-m sprint time (d = 1.3; p < 0.05). Exposure to INT twice weekly is effective and time efficient to improve various measures of physical fitness in highly trained youth male soccer players. [ABSTRACT FROM AUTHOR]

The aims of this study were to investigate the impact of high-intensity, low-volume (HRT) vs. moderate-intensity, and high-volume resistance training (MRT) vs. soccer training only (control group [CON]) on changes in strength, power, and speed and to compare delayed onset muscle soreness (DOMS) between groups in male academy soccer players (ASP). Twenty-two ASP (age: 18 ± 1 years) were assigned to HRT (n = 8), MRT (n = 7), or CON (n = 7). High-intensity resistance training completed 2 sets of 4 repetitions parallel back squat (PBS) repetitions at 90% 1 repetition maximum (1RM), while MRT performed 3 sets of 8 repetitions PBS repetitions at 80% 1RM, both once a week for 6 weeks in-season, alongside regular soccer training. All groups completed the following pretraining and posttraining assessments: 3RM PBS, bilateral vertical and horizontal countermovement jumps (CMJ), squat jump (SJ), and 30-m sprint. Delayed onset muscle soreness was assessed using a visual analog scale throughout training. High-intensity resistance training and MRT experienced similar increases compared with CON in absolute PBS 3RM (p < 0.001), SJ height (p = 0.001), and CMJ height (p = 0.008) after training. There was a greater increase in PBS 3RM relative to body mass after HRT than MRT and CON (p = 0.001) and horizontal CMJ distance improved in HRT but not in MRT or CON (p = 0.011). There was no change in 10-m, 20-m, or 30-m sprint performance in any group. High-intensity resistance training volume was 58 ± 15% lower than that of MRT (p < 0.001), and DOMS measured throughout training did not differ between groups (p = 0.487). These findings suggest that 1 HRT session a week may be an efficient method for improving strength and power in ASP in-season with minimal DOMS. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of age using a large-scale analysis of match physical performance in professional soccer players. A total of 10,739 individual match observations were undertaken on outfield players competing in the first and second divisions of the Spanish soccer professional leagues during the 2017-2018 season, using a computerized tracking system (TRACAB, Chyronhego, New York, NY). The players were classified into five positions and into 5 age groups (<20 years, 20-24.9 years, 25-29.9 years, 30-34.9 years, and ≥35 years). The results showed that (a) professional soccer players aged ≥30 years exhibit a significant decrease (p < 0.01) in the total distance covered, medium-speed running distance, high-speed running (HSR) distance, very HSR (VHSR) distance, sprint distance, and maximum running speed compared with younger players (<30 years); (b) professional soccer players aged ≥35 years exhibit a significant decrease (p < 0.01) in the number of HSR, number of VHSR, and number of sprints compared with younger players (<35 years); and (c) all playing positions reduced their physical performance; however, external midfielders were less affected by age effects. In conclusion, this study demonstrates players' physical match performance reduces with increasing age. Such findings may help coaches and managers to better understand the effects of age on match-related physical performance and may have the potential to assist in decisions regarding recruitment and player list management within professional soccer clubs. [ABSTRACT FROM AUTHOR]