Latest research in football - week 5 - 2023

As previous literature updates, I have performed a PubCrawler search looking for football articles in NCBI Medline (PubMed) and GenBank databases. 


Following studies were retrieved for this week:

#1 Effects of High-Intensity Position-Specific Drills on Physical and Technical Skill Performance in Elite Youth Soccer Players

Reference: J Strength Cond Res. 2022 Nov 23. doi: 10.1519/JSC.0000000000004360. Online ahead of print.

Authors: Cao Cuong Le, Fadi Ma'ayah, Kazunori Nosaka, Daniel Hiscock, Christopher Latella

Summary: Soccer physical preparation has been extensively researched with previous emphasis on high-intensity interval running and small-sided games. However, neither approach considers positional differences. The purpose of this study was to investigate the feasibility and short-term effects of a novel position-specific conditioning training (PSCT) paradigm on physical and technical abilities of young soccer players. Fifteen male Vietnamese professional youth soccer players (16.1 ± 0.4 years, 171.7 ± 4.8 cm, 63.9 ± 3.8 kg) undertook a 3-week control period followed by a 3-week intervention with PSCT drills performed twice per week. Position-specific conditioning training comprised purposely designed drills for attackers, defenders, and wingers, respectively. The intensity and duration were the same for all drills (4 × 4 minutes at ∼90% heart rate maximum [HRmax], separated by a 4-minute recovery at 70% HRmax) but differed in the technical and tactical actions performed. Outcome measures included Yo-Yo intermittent recovery test level 1, repeated sprint ability, 10-m and 30-m sprint time, and the Loughborough Soccer Passing Test for technical skills in a fatigued and nonfatigued state. Position-specific conditioning training drills induced a desirable intensity for effective conditioning purpose (89.0 ± 2.1% HRmax) with low interplayer variability (coefficient of variation = 2.4%). Yo-Yo intermittent recovery test level 1 performance improved (p < 0.05) after the control (Δ178.7 ± 203.3 m) and intervention (Δ176.0 ± 225.7 m) periods without a difference between. These results confirmed the feasibility of PSCT as a novel high-intensity training approach for soccer players. Improvements in aerobic capacity were noted, despite no effect on other physical and technical measures. PSCT may be suitable for individual training, return-to-play stages of rehabilitation, during off-season, or in academy settings when time is not a constraint.



#2 Soccer clubs as avenues for gender transformative socialization of adolescent boys in Cape Town and Mthatha, South Africa: A qualitative study

Reference: PLoS One. 2023 Feb 2;18(2):e0280932. doi: 10.1371/journal.pone.0280932. eCollection 2023.

Authors: Yandisa Msimelelo Sikweyiya, Natalie Leon, Mark N Lurie, Mandla Majola, Christopher J Colvin

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Summary: In this paper, we explore the gender socialization of adolescent boys in soccer clubs, and ask whether there are opportunities for integrating gender transformative elements into that socialization. This qualitative study involved 11 in-depth interviews and informal conversations with male soccer coaches from Gugulethu township and Mthatha town in the Western Cape and Eastern Cape provinces of South Africa, respectively. Data were analyzed using a thematic analysis approach. We found that the coaches felt that the adolescent boys in their soccer clubs faced serious social and emotional challenges, with the boys' poor socio-economic backgrounds and fragmented family structures being major contributors to these challenges. Most coaches also gave themselves the responsibility to try to address some of the challenges faced by their club members. To do this, they employed specific strategies, including creating an alliance with parents and professionals. In the process, the coaches engaged the boys on topics around respect, sexual and reproductive health, and avoiding alcohol, drugs, and involvement in criminal gangs. Some coaches also played a social fathering role to club members as a way of helping them to think differently about their lives, redirect risky practices, and reduce the chance for poor health outcomes. These findings highlight the role of soccer clubs and coaches as potential avenues for health- and equity-promoting gender socialization of adolescent boys.



#3 Injury Burden in Professional European Football (Soccer): Systematic Review, Meta-Analysis, and Economic Considerations

Reference: Clin J Sport Med. 2022 Nov 22. doi: 10.1097/JSM.0000000000001107. Online ahead of print.

Authors: Luca Pulici, Denis Certa, Matteo Zago, Piero Volpi, Fabio Esposito

Summary: We performed a systematic review and meta-analysis to evaluate the injury burden and the related economic cost in European professional male football players. 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. 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). 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.



#4 Interrelationships Between Multiple Speed Tests in Youth Soccer: Are Players Equally Efficient at Performing Different Sprint and Change of Direction Tasks?

Reference: J Strength Cond Res. 2022 Nov 14. doi: 10.1519/JSC.0000000000004341. Online ahead of print.

Authors: Tomás T Freitas, Lucas A Pereira, Pedro E Alcaraz, Eduardo L Cadore, Rafael Grazioli, Paulo H S M Azevedo, Ian Jeffreys, Irineu Loturco

Summary: We investigated the relationships between linear and multidirectional sprint tests in elite young soccer players, using different speed measurements and their associated deficits. Twenty-three under-17 and 17 under-16 soccer players performed, on the same day, 17-m linear sprint (with 10-m split times), curve sprints for "good" and "weak" sides (CSGS and CSWS, respectively), and zigzag and 505 change of direction (COD) tests. The Pearson's product moment test was used to determine the relationships among the tested variables. Significance level was set at p < 0.05. Large and very large significant correlations were observed between CSGS and CSWS and 10-m (r = 0.73 and r = 0.53, respectively; p < 0.0001) and 17-m sprint velocity (r = 0.84 and r = 0.74, respectively; p < 0.0001). Moderate and significant associations were identified between zigzag and 17-m sprint performances (r = 0.40; p = 0.02). No significant relationships were found between 505 performance and 17-m sprint velocity and between the different COD tasks (p > 0.05). Significant correlations were observed between sprint performance at 10- and 17-m and both CS and COD deficits (r values ranging from 0.37 to 0.54; p < 0.05). In general, higher linear sprinting velocities were associated with superior performances in smoother multidirectional tasks (i.e., CS and zigzag tests) but not in more aggressive COD maneuvers (i.e., 505). Faster athletes in linear actions presented greater CS and COD deficits. No associations were detected between the different COD measurements, supporting the notion that the technical and mechanical demands of COD actions are angle and velocity dependent. From a practical perspective, comprehensive speed testing batteries (i.e., incorporating linear sprints, CS, and different COD assessments) should be administered to young soccer players, to better understand their ability to change direction and sprint over multiple trajectories.



#5 Predicting Severity of Head Collision Events in Elite Soccer Using Preinjury Data: A Machine Learning Approach

Reference: Clin J Sport Med. 2022 Nov 4. doi: 10.1097/JSM.0000000000001087. Online ahead of print.

Authors: Gabriel Tarzi, Christopher Tarzi, Ashirbani Saha, Michael D Cusimano

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Summary: The aim was to develop machine learning (ML) models that predict severity of head collision events (HCEs) based on preinjury variables and to investigate which variables are important to predicting severity. Data on HCEs were collected with respect to severity and 23 preinjury variables to create 2 datasets, a male dataset using men's tournaments and mixed dataset using men's and women's tournaments, to perform ML analysis. Machine learning analysis used a random forest classifier based on preinjury variables to predict HCE severity. Elite athletes participating in analyzed tournaments were investigated with 23 preinjury variables collected for each HCE. Predictive ability of the ML models and association of important variables was used as main outcome measure. The ML models had an average area under the receiver operating characteristic curve for predicting HCE severity of 0.73 and 0.70 for the male and mixed datasets, respectively. The most important variables for prediction were the mechanism of injury and the event before injury. In the male dataset, the mechanisms "head-to-head" and "knee-to-head" were together significantly associated (P = 0.0244) with severity; they were not significant in the mixed dataset (P = 0.1113). In both datasets, the events "corner kicks" and "throw-ins" were together significantly associated with severity (male, P = 0.0001; mixed, P = 0.0004). ML models accurately predicted the severity of HCE. The mechanism and event preceding injury were most important for predicting severity of HCEs. These findings support the use of ML to inform preventative measures that will mitigate the impact of these preinjury factors on player health.



#6 Does Prematch Neuromuscular Performance Affect Running Performance in Collegiate Elite Female Soccer?

Reference: J Strength Cond Res. 2022 Oct 18. doi: 10.1519/JSC.0000000000004344. Online ahead of print.

Authors: Ai Ishida, Garrison Draper, Jason B White, S Kyle Travis

Summary: The purpose of this study was to investigate whether prematch neuromuscular performance affected match physical performance by player position in Division I collegiate female soccer. Fourteen players participated (20.7 ± 1.3 years; 165.1 ± 6.0 cm; 63.3 ± 7.0 kg) in this study. Players were selected based on being free from injuries, playing for a duration of ≥72 minutes, and match intervals were ≥2 days. Data included 73 observations (n = 5 defenders, n = 7 midfielders, and n = 2 forward) from 14 official matches. Prematch neuromuscular performance was assessed using countermovement jump (CMJ) with polyvinyl chloride pipe on dual force plates. Countermovement jump variables included jump height (JH) and relative peak power (RPP). Match physical performance included average speed, high-speed running (HSR), and number of high accelerations and decelerations. Linear mixed model was compiled with fixed effects of loaded with fixed effect of JH, RPP, and position and random effects per individual player. In CMJ and player position model, RPP was a significant predictor for average HSR (p = 0.003) while fixed effects of JH and position were not significant (p = 0.15-0.86). The fixed and random effects explained 34.8 and 42.1% of variances in average HSR. In CMJ-only model, RPP significantly predicted the variances in average HSR (p = 0.001). The fixed effects and random effects of the model explained 22.7 and 51.8% of the variance in average HSR. However, position-only was not a significant predictor for average HSR in the position-only model (p = 0.26 and 0.33). Prematch CMJ RPP may be the greatest predictor of average HSR in collegiate female soccer.



#7 Relationships between training load, peak height velocity, muscle soreness and fatigue status in elite-level young soccer players: a competition season study

Reference: BMC Pediatr. 2023 Feb 3;23(1):55. doi: 10.1186/s12887-023-03869-7.

Authors: Hadi Nobari, Özgür Eken, Okan Kamiş, Rafael Oliveira, Pablo Prieto González, Rodrigo Aquino

Summary: This study aimed to compare training load parameters, delayed onset muscle soreness (DOMS), and fatigue status between season periods (1st and 2nd halves) in U14 soccer players and to analyze the relationships between training load parameters based on season periods (1st and 2nd halves) with peak height velocity (PHV), DOMS, and fatigue status in under-14 (U14) young elite soccer players. Additionally, it was intended to analyze if fatigue, DOMS and PHV could explain training load parameters across the season. Twenty U14 players that competed in the national league participated in this study. The players were monitored during the whole season (26 weeks), and evaluations were carried out at the end of the in-season. Anthropometric and body composition parameters and the maturity offset of each player were utilized to compute each player's age at PHV. Players reported their levels of DOMS and fatigue status using Hooper index questionnaires. The internal load was monitored using the rating of perceived exertion (RPE). Acute weekly internal load (AW), chronic weekly internal load (CW), acute: chronic workload ratio (ACWR), training monotony (TM), and training strain (TS) were also obtained. The main results showed that TM was higher in the 2nd half, while CW, AW and DOMS were higher in the 1st half of the season. Moreover, the main correlations showed a positive correlation between PHV and TS (2nd half of the season) and between fatigue and TM (1st half of the season). In conclusion, variations in well-being status and PHV cannot explain the variations in internal training loads in elite U14 soccer players. In addition, internal training load indices during the first half of the competitive season can promote a fundamental base for progression loads during the second period of the competitive season.



#8 Mechanisms of Hamstring Injury in Professional Soccer Players: Video Analysis and Magnetic Resonance Imaging Findings

Reference: Clin J Sport Med. 2022 Nov 25. doi: 10.1097/JSM.0000000000001109. Online ahead of print.

Authors: Aleksi Jokela, Xavier Valle, Jussi Kosola, Gil Rodas, Lluís Til, Maria Burova, Pavel Pleshkov, Håkan Andersson, Giulio Pasta, Paolo Manetti, Gabriel Lupón, Ricard Pruna, Alvaro García-Romero-Pérez, Lasse Lempainen

Summary: The aim was to describe the injury mechanisms and magnetic resonance imaging (MRI) findings in acute hamstring injuries of male soccer players using a systematic video analysis. Descriptive case series study of consecutive acute hamstring injuries from September 2017 to January 2022. Professional male soccer players aged between 18 and 40 years, referred for injury assessment within 7 days after an acute hamstring injury, with an available video footage of the injury and positive finding on MRI. Hamstring injury mechanisms (specific scoring based on standardized models) in relation to hamstring muscle injury MRI findings were used as independent variables and Hamstring injury mechanism (playing situation, player/opponent behavior, movement, and biomechanical body positions) and MRI injury location as main outcome measures. Fourteen videos of acute hamstring injuries in 13 professional male soccer players were analyzed. Three different injury mechanisms were seen: mixed-type (both sprint-related and stretch-related, 43%), stretch-type (36%), and sprint-type (21%). Most common actions during injury moments were change of direction (29%), kicking (29%), and running (21%). Most injuries occurred at high or very high horizontal speed (71%) and affected isolated proximal biceps femoris (BF) (36%). Most frequent body positions at defined injury moments were neutral trunk (43%), hip flexion 45-90 degrees (57%), and knee flexion <45 degrees (93%). Magnetic resonance imaging findings showed that 79% were isolated single-tendon injuries. According to a video analysis, most hamstring injuries in soccer occur during high-speed movements. Physicians should suspect proximal and isolated single-tendon-most often BF-hamstring injury, if represented injury mechanisms are seen during game play. In addition to sprinting and stretching, also mixed-type injury mechanisms occur.



#9 Power, Endurance, and Body Composition Changes Over a Collegiate Career in National Collegiate Athletic Association Division I Women Soccer Athletes

Reference: J Strength Cond Res. 2023 Jan 18.  doi: 10.1519/JSC.0000000000004413. Online ahead of print.

Authors: Bridget A McFadden, Brittany N Bozzini, Harry P Cintineo, Samuel P Hills, Alan J Walker, Alexa J Chandler, David J Sanders, Mark Russell, Shawn M Arent

Summary: 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.



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

Reference: J Strength Cond Res. 2023 Feb 1. doi: 10.1519/JSC.0000000000004472. Online ahead of print.

Authors: Lucas A Pereira, Tomás T Freitas, Santiago Zabaloy, Ricardo C A Ferreira, Matheus L Silva, Paulo H S M Azevedo, Irineu Loturco

Summary: 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.



#11 Pain provocation tests and clinical entities in male football players with longstanding groin pain are associated with pain intensity and disability

Reference: Musculoskelet Sci Pract. 2023 Jan 10;63:102719. doi: 10.1016/j.msksp.2023.102719.

Authors: Mathias F Nielsen, Lasse Ishøi, Carsten Juhl, Per Hölmich, Kristian Thorborg

Summary: Clinical examination of male football players with longstanding groin pain can be considered difficult. Pain provocation tests are used to examine and classify longstanding groin pain into clinical entities as adductor-, iliopsoas-, inguinal-, and pubic-related. It is unknown if pain provocation tests and clinical entities are associated with pain intensity and disability. The aim was to investigate if the number of positive pain provocation tests and clinical entities are associated with pain intensity and disability, measured by the Copenhagen 5-Second Squeeze Test (5SST) and the Copenhagen Hip and Groin Outcome Score (HAGOS), respectively. Forty male football players (age: mean 24 years [SD: 3.2]; height: mean 182 cm [SD: 5.7]; weight: mean 78 Kg [SD: 6.6]) with longstanding groin pain for a median of 8.5 months (IQR: 4-36) were included. The players underwent a bilateral groin examination with 33 pain provocation tests and were classified with clinical entities (0-7) based on the test findings. The number of positive pain provocation tests (median 10, range 2-23) correlated with pain intensity (5SST: rs = 0.70 [95% CI: 0.50, 0.83]) and disability (HAGOS subscales Sport: rs =-0.62 [95% CI: -0.81, -0.36], Pain: rs = -0.38 [95% CI: -0.69, -0.06], Symptoms: rs = 0.52 [95% CI: -0.73, -0.24], ADL: rs = -0.48 [95% CI: -0.71, -0.18]). The number of clinical entities (median 3, range: 1-7) showed similar but weaker correlations to pain intensity and disability. In male football players with longstanding groin pain, the number of positive pain provocation tests and clinical entities shows weak to strong correlations with pain intensity and disability. Consequently, when pain intensity and disability are severe, a higher number of pain provocation tests may be positive, and more clinical entities may be present.



#12 Adjusting to Changing Environments: Virtual Preseason SCAT5 Assessment in Canadian Male Youth Football Players

Reference: Clin J Sport Med. 2022 Nov 8. doi: 10.1097/JSM.0000000000001086. Online ahead of print.

Authors: Reid A Syrydiuk, Linden C Penner, Stacy Sick, Paul Eliason, Jean-Michel Galarneau, Benjamin Leggett, Olivia Galea, Kathryn J Schneider, Carolyn A Emery

Summary: The aim was to provide preseason reference scores for Canadian youth tackle football players on the Sport Concussion Assessment Tool 5 (SCAT5) and to examine whether age, concussion history, and self-reported medical diagnoses are associated with SCAT5 subcomponent performance. Five hundred one male youth football players (ages 13-18 years) participated in the 2021 season. SCAT5 subcomponents were assessed by age group (13-14, 15-16, 17-18), concussion history (0, 1, 2+, and yes/no), and self-reported diagnoses (headache disorder, attention-deficit/hyperactive disorder, learning disability/dyslexia, and depression, anxiety, or other psychiatric disorder). Virtual video administration (vs traditional in-person testing) of the SCAT5 was completed, and subcomponent scores included total number of symptoms (/22), symptom-severity score (/132), Standardized Assessment of Concussion [orientation (/5), immediate memory (/30), concentration (/5), delayed recall (/10)], and modified Balance Error Scoring System (/30). Kruskal-Wallis, one-way analysis of variance , Mann-Whitney U, or independent t tests were used to assess possible associations depending on number of groups and data normality. Virtual SCAT5 assessment scores across all outcomes did not differ by age group or concussion history. The median number of symptoms and median symptom-severity score at baseline was 2, and 173 players (34.5%) reported no symptoms. Median total number of errors on the modified Balance Error Scoring System was 3. Participants with certain self-reported diagnoses (attention-deficit/hyperactive disorder, dyslexia) demonstrated poorer performance on some SCAT5 subcomponents (symptom reporting, Standardized Assessment of Concussion). Baseline SCAT5 performance did not differ by age group or concussion history in male youth football players. Diagnoses of the self-reported disorders examined may be important considerations for interpretation of the SCAT5 assessment.



#13 Bilateral Ischial Tuberosity Stress Fractures in an Adolescent Football Player: A Case Report

Reference: Clin J Sport Med. 2022 Dec 6. doi: 10.1097/JSM.0000000000001103. Online ahead of print.

Authors: Jared M Jones, Grant M Wallenfelsz, Phillip R Worts, Andrew M Wong

Summary: Pelvic stress fractures are rare, making up an estimated 1% to 7% of all stress fractures with the primary locations being the pubic rami, pubic symphysis, and sacrum. Two cases of stress fractures of the ischium have been previously described in the literature, with both occurring in the ischial body. In this case, a 17-year-old high school American football player presented with nonspecific pelvic pain and bilateral point tenderness on deep palpation of the ischial tuberosities. Advanced imaging identified bilateral ischial tuberosity stress fractures. This report outlines the diagnosis and management of the first reported case of bilateral ischial tuberosity stress fractures. We report how ischial tuberosity stress fractures present clinically, potential management strategies, and highlight the use of computed tomography imaging for pelvic stress fractures. Knowledge of unusual stress fracture locations may improve early diagnosis, limit complications, reduce healthcare costs, and promote an accelerated recovery time.



#14 Health football beats them all: subgroup analysis of the 3F (Fit&Fun with Football) study on white coat hypertension, sustained hypertension, dippers, nondippers, and on pharmacologically un(treated) arterial hypertension

Reference: J Hypertens. 2022 Dec 19. doi: 10.1097/HJH.0000000000003360. Online ahead of print.

Authors: Bastian Schrader, Charis Conradi, Stephan Lüders, Bernhardt Vaske, Martin Koziolek, Eugen Gehlenborg, Hermann Haller, Albrecht Elsässer, Joachim Schrader

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Summary: The 3F study (Fit&Fun with Football) demonstrated a significant reduction in blood pressure, antihypertensive medication, body weight, stress and depression through health football. Health football could be a popular tool to unleash the full preventive potential of physical activity. This work analyses the effect of health football on hypertensive subgroups dipper, nondipper, white coat hypertension (WCH), sustained hypertension, (un)treated hypertensive patients (UH, TH). A prospective interventional study with 1-year follow-up. Football group (FG): n = 103, 'health'-football training (1×/week, 90 min) led by licensed football coaches. Physical inactive, hypertensive patients older than 45 years were compared with a control group (CG) (n = 105). Subgroups were divided by ambulatory blood pressure monitoring (ABPM), casual blood pressure (CBP), medication schedule and compared by blood pressure (BP), laboratory results and weight. In all three subgroups (WCH vs. sustained hypertension, TH vs. UH, D vs. ND), health football reduced BP and weight significantly compared with the CG, and compared with the admission. An even greater effect in CBP was found in people with WCH than in sustained hypertension (FG: WCH: 141-127 mmHg, sustained Hypertension (SH): 142-132 mmHg; CG: WCH: 141-143 mmHg, SH: 140-141 mmHg). In contrast, the significant reduction in CBP and ABPM was comparable in treated and untreated patients, although antihypertensive drugs were reduced significantly more frequently in FG than in CG. BP reduction in nondippers and dippers was also comparable. In the nondipper group, nocturnal BP was significantly reduced in the FB (122.0-111.5 mmHg), but not in the CG or the dippers. All evaluated football subgroups achieved a significant BP reduction (compared with CG). This applied to dipper, nondipper, (un)treated hypertension, WCH and SH. All mentioned subgroups displayed a clear benefit. The even greater reduction in BP in WCH demonstrates the importance of physical activity before the additional prescription of antihypertensive medications, underscoring the recommendations of the ESC and ISH in WCH.



#15 Risk factors for hamstring muscle injury in male elite football: medical expert experience and conclusions from 15 European Champions League clubs

Reference: BMJ Open Sport Exerc Med. 2023 Jan 24;9(1):e001461. doi: 10.1136/bmjsem-2022-001461. eCollection 2023.

Authors: Jan Ekstrand, Peter Ueblacker, Wart Van Zoest, Raymond Verheijen, Bruno Vanhecke, Maikel van Wijk, Håkan Bengtsson

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Summary: The aim was to describe the perceived importance of suggested hamstring injury risk factors according to chief medical officers (CMOs) of European male professional football clubs. A secondary objective was to compare if these perceptions differed between teams with a lower-than-average hamstring injury burden and teams with a higher than average hamstring injury burden. First, CMOs of 15 European professional male football clubs were asked to suggest risk factors for hamstring injury in their club. The perceived importance of the suggested risk factors was then rated by all participants on a 5-graded Likert scale. Participating teams were divided in two groups depending on their hamstring injury burden during the 2019/2020 and 2020/2021 seasons. The LOW group consisted of seven teams that had a lower than average hamstring injury burden. The HIGH group consisted of eight teams that had a higher-than-average hamstring injury burden. Twenty-one risk factors were suggested. The majority were extrinsic in nature, associated with coaching staff, team or club rather than players themselves. 'Lack of communication between medical staff and coaching staff' had the highest average importance (weighted average=3.7) followed by 'Lack of regular exposure to high-speed football during training sessions' (weighted average=3.6). The HIGH group perceived the player factors fatigue and wellness as more important than the LOW group. According to CMOs recruited in this study, most risk factors for hamstring injuries are extrinsic and associated with the club and coaching staff, and not the players themselves.



#16 Variations in cumulative workload and anaerobic power in adolescent elite male football players: associations with biological maturation

Reference: BMC Sports Sci Med Rehabil. 2023 Jan 31;15(1):11. doi: 10.1186/s13102-023-00623-5.

Authors: Hadi Nobari, Armin Gorouhi, Javier Mallo, Demetrio Lozano, Pablo Prieto-González, Elena Mainer-Pardos

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Summary: It is considered that the maturity condition of young football players is related to their physical performance during short high-intensity efforts dependent on anaerobic power ability. Hence, the aim was to determine possible relationships between maturity status and training intensity by measuring the footballer´s peak height velocity (PHV), maturity offset and anaerobic power. Seventeen youth male players of different playing positions participated in the study and performed tests at three different stages of the season (early-, mid- and end-season) All the anthropometric parameters and biomarkers related to maturation were controlled during the season. The training intensity and load was monitored and the anaerobic power of the players was assessed by a running-based anaerobic sprint test (RAST). The analysis of all the recorded data revealed a positive relationship between PHV and anaerobic power in the early- and end-season stages (p < 0.05). Maturity offset and anaerobic power (mean RAST) showed an absolute correlation in early- and end -season stages (r: - 0.39 to 0.91). The multiple linear regression analysis revealed that min RAST was the best predictor for both PHV and maturity offset. The analysis of the training intensity and workloads showed a positive effect on the performance in the fitness test (p < 0.05). Additionally, players experienced less fatigue at the end-season stage than at the early-season. The results show that coaches might benefit from monitoring training loads and the maturity status of the players in order to enhance their physical performance during the season.



#17 Sensitivity of rapid antigen tests for COVID-19 during the Omicron variant outbreak among players and staff members of the Japan Professional Football League and clubs: a retrospective observational study

Reference: BMJ Open. 2023 Jan 30;13(1):e067591. doi: 10.1136/bmjopen-2022-067591.

Authors: Michio Murakami, Hitoshi Sato, Tomoko Irie, Masashi Kamo, Wataru Naito, Tetsuo Yasutaka, Seiya Imoto

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Summary: Rapid antigen tests have been used to prevent the spread of the COVID-19; however, there have been concerns about their decreased sensitivity to the Omicron variant. In this study, we assessed the sensitivity and specificity of the rapid antigen test compared with the PCR test among the players and staff members of the Japan Professional Football League and clubs. Furthermore, we evaluated the relationship between the sensitivity and the duration from the onset of symptoms to testing or vaccine status. We used 656 results from both the rapid antigen and PCR tests for COVID-19 using samples collected on the same day from 12 January to 2 March 2022, during the Omicron variant outbreak in Japan. The sensitivity of the rapid antigen test compared with the PCR test was 0.63 (95% CI: 0.53 to 0.73) and the specificity was 0.998 (95% CI: 0.995 to 1.000). There were no significant associations between the sensitivity and the duration from the onset of symptoms to testing (including asymptomatic cases in the category) or vaccination status (p>0.05) with small effect sizes (Cramer's V or φ: ≤0.22). Even during the Omicron outbreak, the sensitivity of the rapid antigen tests did not depend on the duration from the onset of symptoms to testing.



#18 Match performance of football teams in different competition phases: Analysis on the data of eight consecutive seasons in the Chinese Super League

Reference: Front Psychol. 2023 Jan 11;13:1069082. doi: 10.3389/fpsyg.2022.1069082. eCollection 2022.

Authors: Pei Li, Shisheng Zhong, Paweł Chmura, Hongyou Liu

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Summary: The study aims to quantify the variation in the physical and technical match performance of football teams in different months of a season in the Chinese Super League (CSL). Data of 1,899 matches in the seasons 2012-2019 of CSL collected by Amisco Pro® were analysed. The generalised mixed modelling was employed to estimate the per match mean values of six physical performance-related parameters and 16 technical performance-related parameters of CSL teams in every month of all the eight seasons. Results showed that: (1) the mean values of all the analysed physical performance-related parameters (total/sprint/HSR/MSR distance, sprint/HSR efforts) of CSL teams through a season were characterised like a 'U' shape, the highest value was observed in the beginning of season (March), then decreased gradually, reaching the lowest in August, and rebounded progressively from September to November; (2) the mean values of eight technical performance-related parameters (goals, shots, shot accuracy, individual possession, individual possession in the last third, crosses, cross accuracy and yellow cards) presented trivial changes through the whole season; (3) the number of passes, passes per shot, forward passes, and time in individual possession showed trivial changes from March to October, but showed a substantially increase in November (the last month of season); (4) Pass accuracy, forward pass accuracy, and the number of mean ball touches per individual possession substantially increased in June, July and August, whilst the number of challenges, ground challenges, air challenges, tackles and fouls all substantially decreased in these 3 months. These results could provide detailed information to help the practitioners choose the best training and match preparation strategy in the means of periodisation in different season phases.


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