Latest research in football - week 2 - 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 Game Weekly Frequency on Subjective Training Load, Wellness, and Injury Rate in Male Elite Soccer Players

Reference: Int J Environ Res Public Health. 2022 Dec 29;20(1):579. doi: 10.3390/ijerph20010579.

Authors: Rim Sioud, Raouf Hammami, Javier Gene-Morales, Alvaro Juesas, Juan C Colado, Roland van den Tillaar

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Summary: The aim was to compare the effects of playing one or two games per week on subjective perceived exertion (RPE) and (RPE-based) training load, monotony index, sleep, stress, fatigue, and muscle soreness (Hooper index), total mood disturbance, and injury rate in elite soccer players. Fourteen males from a first-division soccer club (age: 24.42 ± 4.80 years) competed in two games per week for six weeks and one game per week for twelve weeks (a total of 24 games). Paired t-tests and non-parametric Wilcoxon signed ranks evaluated the significance of the differences (p < 0.05). The main findings were that RPE was significantly larger when playing two games per week compared with one game. However, subject total and mean training load, mood disturbance, monotony, and subjective perception of sleep, stress, fatigue, muscle soreness monitoring (Hooper index), and the number of injuries were not different. The findings suggested that competing in two matches per week does not negatively influence injury rate and players' perceptions of training load or wellness, even though players perceive two games per week as more physically demanding compared with one game per week.



#2 High Levels of PM10 Reduce the Physical Activity of Professional Soccer Players

Reference: Int J Environ Res Public Health. 2022 Dec 30;20(1):692. doi: 10.3390/ijerph20010692.

Authors: Michał Zacharko, Robert Cichowicz, Adam Depta, Paweł Chmura, Marek Konefał

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Summary: The aim of this study is to determine the impact of air quality, analyzed on the basis of the PM10 parameter in three regions of Poland, on the physical activity of soccer players from the Polish Ekstraklasa. The study material consisted of 4294 individual match observations of 362 players during the 2019/2020 domestic season. The measured indices included the parameter of air quality-PM10-and players' physical activities: total distance (TD) and high-speed running (HSR). Poland was divided into three regions (North, Central, South). The statistical analysis of particulate matter (PM) and athletes' physical activities, compared by region, revealed the effects in relation to the PM10 (H = 215.6566(2); p = 0.0001) and TD (H = 28.2682(2); p = 0.0001). Players performed better in regards to physical parameters in the North Region, where air pollution is significantly lower than in other regions. This means that even a short stay in more polluted regions can reduce the performance of professional footballers, which can indirectly affect the outcome of the match. Therefore, greater actions should be taken to improve air quality, especially through changes in daily physical activity, as this will reduce the carbon footprint.



#3 Effects of Virtual Reality Exercises versus Isokinetic Exercises in comparison with Conventional Exercises on the Imaging Findings and Inflammatory Biomarker Changes in Soccer Players with Non-Specific Low Back Pain: A Randomized Controlled Trial

Reference: Int J Environ Res Public Health. 2022 Dec 28;20(1):524. doi: 10.3390/ijerph20010524.

Authors: Gopal Nambi, Mshari Alghadier, Faizan Zaffar Kashoo, Osama R Aldhafian, Naif A Nwihadh, Ayman K Saleh, Mohamed A Omar, Tohamy G T Hassan, Mohamed Nagah Ahmed Ibrahim, Hassan Fathy El Behairy, Abdehamid A Attallah, Mohammed Abdelgwad Ismail

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Summary: Chronic non-specific low back pain (CNLBP) is the most common musculoskeletal problem. The purpose of this study was to investigate the effects of advanced physiotherapeutic exercise programs on imaging findings and inflammatory biomarkers in soccer players with CNLBP. In total, 60 CNLBP participants were divided into virtual reality exercise (VRE; n = 20), isokinetic exercise (IKE; n = 20), and conventional exercise (n = 20) groups. Pain intensity, imaging findings (muscle cross-sectional area (CSA) and muscle thickness), and changes in inflammatory biomarkers (CRP, TNF-α, IL-2, IL-4, and IL-6) were measured at baseline and after four weeks. After four weeks of intervention, there was a significant improvement (p = 0.001) in pain intensity for the VRE vs. IKE (0.7; CI 95% 0.38 to 1.07) and VRE vs. conventional (3.0 CI 95% 2.68 to 3.31) groups. The IKE group showed a greater number of significant changes in muscle CSA and muscle thickness than the other two groups (p < 0.001). Moreover, the VRE group showed significant improvement in inflammatory biomarker measures compared with the other two groups (p < 0.001). In CNLBP, virtual and isokinetic exercises had equal effects on reducing pain intensity. Isokinetic exercise is beneficial in increasing the muscle CSA and thickness, and virtual exercises are helpful for attenuating the inflammation process in soccer players with CNLBP.



#4 Contextualised high-intensity running profiles of elite football players with reference to general and specialised tactical roles

Reference: Biol Sport. 2023 Jan;40(1):291-301. doi: 10.5114/biolsport.2023.116003. Epub 2022 May 10.

Authors: Wonwoo Ju, Dominic Doran, Richard Hawkins, Mark Evans, Andy Laws, Paul S Bradley

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Summary: The present study aimed to contextualise physical metrics with tactical actions according to general and specialised tactical roles. A total of 244 English Premier League players were analysed by coding player's physical-tactical actions via the fusion of tracking data and video. Data were analysed across 5 general (Central Defensive Players = CDP, Wide Defensive Players = WDP, Central Midfield Players = CMP, Wide Offensive Players = WOP, Central Offensive Players = COP) and 11 specialised positions (Centre Backs = CB, Full-Backs = FB, Wing-Backs = WB, Box-to-Box Midfielders = B2BM, Central Defensive Midfielders = CDM, Central Attacking Midfielders = CAM, Wide Midfielders = WM, Wide Forwards = WF, Centre Forwards = CF). COP covered more distance at high-intensity (> 19.8 km · h-1) when performing actions such as 'Break into Box', Run in Behind/Penetrate', and 'Close Down/Press' than other positions (ES: 0.6-5.2, P < 0.01). WOP covered more high-intensity 'Run with Ball' distance (ES: 0.7-1.7, P < 0.01) whereas WDP performed more 'Over/Underlap' distance than other positions (ES: 0.9-1.4, P < 0.01). CDP and WDP covered more high-intensity 'Covering' distances than other positions (ES: 0.4-2.4, P < 0.01). Nonetheless, data demonstrated that implementing specialised positional analysis relative to a generalised approach is more sensitive in measuring physical-tactical performances of players with the latter over or underestimating the match demands of the players compared to the former. A contextualised analysis may assist coaches and practitioners when designing position or even player-specific training drills since the data provides unique physical-tactical trends across specialised roles.



#5 Positional and temporal differences in peak match running demands of elite football

Reference: Biol Sport. 2023 Jan;40(1):311-319. doi: 10.5114/biolsport.2023.116006. Epub 2022 May 10.

Authors: Bradley Thoseby, Andrew D Govus, Anthea C Clarke, Kane J Middleton, Ben J Dascombe

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Summary: Temporal changes in the total running demands of professional football competition have been well documented, with absolute running demands decreasing in the second half. However, it is unclear whether the peak match running demands demonstrate a similar decline. A total of 508 GPS files were collected from 44 players, across 68 matches of the Australian A-League. GPS files were split into the 1st and 2nd half, with the peak running demands of each half quantified across 10 moving average durations (1-10 min) for three measures of running performance (total distance, high-speed distance [> 19.8 km · h-1] and average acceleration). Players were categorised based on positional groups: attacking midfielder (AM), central defender (CD), defensive midfielder (DM), striker (STR), wide defender (WD) and winger (WNG). Linear mixed models and effect sizes were used to identify differences between positional groups and halves. Peak running demands were lower in the second half for STR across all three reported metrics (ES = 0.60-0.84), with peak average acceleration lower in the second half for DM, WD and WNG (ES = 0.60-0.70). Irrespective of match half, AM covered greater peak total distances than CD, STR, WD and WIN (ES = 0.60-2.08). Peak high-speed distances were greater across both halves for WIN than CD, DM and STR (ES = 0.78-1.61). Finally, STR had lower peak average acceleration than all positional groups across both halves (ES = 0.60-1.12). These results may help evaluate implemented strategies that attempt to mitigate reductions in second half running performance and inform position specific training practices.



#6 Hamstring muscle architecture and myotonometer measurements in elite professional football players with a prior strained hamstring

Reference: Biol Sport. 2023 Jan;40(1):93-99. doi: 10.5114/biolsport.2023.112092. Epub 2022 Jan 3.

Authors: F Javier Núñez, Juan Carlos Martínez, Jan-Arie Overberg, Nacho Torreno, Luis Suarez-Arrones

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Summary: The purpose of this study was to compare the fascicle length, angle pennation and mechanical properties of the biceps femoris long head (BFlh) in dominant and non-dominant limbs in previously injured and uninjured professional football players. Fifteen professional football players were recruited to participate in this study. Seven players had suffered a BFlh injury during the previous season. Myotonometry mechanical properties were measured in the proximal, common tendon and distal BFlh using MyotonPRO, and angle pennation and fascicle length were also measured. We observed significantly higher distal BFlh frequency, stiffness, decrement, relaxation and creep than in the common tendon and proximal BFlh. The previously injured players showed significantly higher frequency and stiffness, and lower relaxation and creep in the dominant BFlh than did uninjured players. There were no significant differences between the fascicle length and angle pennation in previously injured and uninjured BFlh. Myotonometric measurement provides a quick and inexpensive way to check the properties of the BFlh in professional football players. Professional football players with previous BFlh injury showed higher intrinsic tension and a poorer capacity to deform than did players with no injury to the BFlh.



#7 Development of novel calibration model(s) to predict whole-body density in professional football players

Reference: Sci Med Footb. 2023 Jan 17;1-9. doi: 10.1080/24733938.2023.2166680. Online ahead of print.

Authors: Claire Mills, Mark De Ste Croix, David James, Stephen-Mark Cooper 

Summary: Questions continue to be raised about the validity that is in existence to estimate Db, in professional male footballer players. Phase 1: n = 28 anthropometric variables were used on n = 206 footballers, using regression analyses to determine standard error of estimate and R2. A cut-off correlation coefficient set at r = 0.950 and 90% R2. Phase 2: all variables (z-scores, −x�- = 0.0, SD = ±1.0) to help reduce heteroscedasticity, β, r, t, significance of t and P-values were calculated. Phase 3: a forced stepwise-backwards regression analysis approach with nine predictors which met the acceptance criteria (r = 0.950, R2 = 90% and β weights) was used to develop a 'best fit' and a 'practical' calibration model. Phase 4: cross-validation of the two newly developed calibration method using LoA. The 'best fit' model SEM (0.115 g ml-1), the highest R2 (6.6%) (P ≤ 0.005), whereas the 'practical' calibration model SEM (0.115 g ml-1), R2 (4.7%) (P ≤ 0.005) with r values = 0.271 and 0.596 and R2 (%) coefficients = 0.3526 for the 'best fit' and 'practical' calibration models, respectively (P = 0.01). The two calibration models supported an ecologically and statistically valid contribution and can provide sound judgements about professional footballers' body composition.



#8 From Optical Tracking to Tactical Performance via Voronoi Diagrams: Team Formation and Players' Roles Constrain Interpersonal Linkages in High-Level Football

Reference: Sensors (Basel). 2022 Dec 27;23(1):273. doi: 10.3390/s23010273.

Authors: Nelson Caldeira, Rui J Lopes, Dinis Fernandes, Duarte Araujo

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Summary: Football performance behaviour relies on the individual and collective perceptual attunement to the opportunities for action (affordances) available in a given competitive environment. Such perception-action coupling is constrained by players' spatial dominance. Aiming to understand the influence of team formation and players' roles in their dynamic interaction (interpersonal linkages), Voronoi diagrams were used to assess the differences in players' spatial dominance resulting from their interactions according to ball-possession status in high-performance football. Notational (i.e., team formation, players' role, and ball-possession status) and positional data (from optical sensors) from ten matches of the men's French main football league were analysed. Voronoi diagrams were computed from players' positional data for both teams. Probability density functions of the players' Voronoi cell areas were then computed and compared, using the Kolmogorov-Smirnov test, for the different variables (i.e., team formation, player role, and ball-possession status) and their classes. For these variables, the players' Voronoi cell areas presented statistical differences, which were sensitive to team formation classes (i.e., defenders, midfielders, and forwards) and relative pitch location (interior or exterior in the effective play space). Differences were also found between players with similar roles when in different team formations. Our results showed that team formation and players' roles constrain their interpersonal linkages, resulting in different spatial dominance patterns. Using positional data captured by optical sensors, Voronoi diagrams can be computed into compound variables, which are meaningful for understanding the match and thus offer information to the design representative training tasks.



#9 Modulation of Oxidative Stress and Antioxidant Response by Different Polyphenol Supplements in Five-a-Side Football Players

Reference: Nutrients. 2022 Dec 30;15(1):177. doi: 10.3390/nu15010177.

Authors: Lucrecia Carrera-Quintanar, Lorena Funes, María Herranz-López, Néstor Vicente-Salar, Raul Bonet-García, Carles Blasco-Peris, Vicente Micol, Antoni Pons, Enrique Roche

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Summary: Oxidative stress is associated with playing soccer. The objective of the present report was to study the influence of different polyphenolic antioxidant-rich beverages in five-a-side/futsal players. The study was performed with a no supplemented control group (CG) and two supplemented groups with an almond-based beverage (AB) and the same beverage fortified with Lippia citriodora extract (AB + LE). At day 22, participants played a friendly futsal game. Blood extractions were performed at the beginning of intervention (day 1), before and after match (day 22) to determine oxidative stress markers and antioxidant enzyme activities in plasma, neutrophils and peripheral blood mononuclear cells (PBMCs). Malondialdehyde increased significantly in controls after the match in neutrophils, PBMCs and plasma compared to pre-match. Protein carbonyls also increased after the match in plasma in CG. In addition, malondialdehyde levels in neutrophils were significantly lower in the supplemented groups compared to controls. Post-match samples showed significant increases in neutrophil antioxidant activities in CG. Supplemented groups displayed variable results regarding neutrophil antioxidant activities, with superoxide dismutase activity significantly lower than in controls. Finally, post-match myeloperoxidase activity increased significantly in controls compared to pre-match and supplemented groups. In conclusion, polyphenolic antioxidant and anti-inflammatory supplements could be instrumental for optimal recovery after high intensity futsal games.



#10 Dietary Intake, Body Composition and Performance of Professional Football Athletes in Slovenia

Reference: Nutrients. 2022 Dec 24;15(1):82. doi: 10.3390/nu15010082.

Authors: Matjaž Macuh, Jana Levec, Nenad Kojić, Bojan Knap

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Summary: This is the first study to examine the nutritional status of professional Slovenian football players. This study aimed to analyze the dietary intake of elite football players during their preparation phase of the season and to investigate whether there is a relationship between energy and macronutrient intake with body composition and physical performance. Twenty-three footballers completed a three-day dietary and physical activity diary and underwent body composition measurements via bioelectrical impedance vector analysis (BIVA). Fifteen participants also took part in the Cooper treadmill test to assess their physical performance in correlation with their nutritional intake. Football players had an energy intake that was significantly too low for their needs, reflecting low energy availability. The average carbohydrate (CHO) intake was below the Union of European Football Associations (UEFA) recommendations, i.e., &lt;4 g CHO/kg body weight (BW). Additionally, players had adequate intakes of protein and fat, and inadequate intakes of saturated fat, fiber, calcium and vitamin D. There was a positive correlation between protein intake and lean body mass. Additionally, a negative correlation was observed between body fat mass and carbohydrate intake as well as between performance with the percentage of energy intake from fat. Results of this study highlight what aspects of nutrition might be improved upon in professional football players to maximize performance, longevity and body composition of athletes, as well as the necessity of a nutritionist role in this process.



#11 The Influence of Stud Characteristics of Football Boots Regarding Player Injuries

Reference: Int J Environ Res Public Health. 2022 Dec 30;20(1):720. doi: 10.3390/ijerph20010720.

Authors: Alejandro Castillo-Domínguez, Marcelino Torrontegui-Duarte, Joaquín Páez-Moguer, Álvaro Gómez-Del-Pino, Pablo Cervera-Garvi, Elena Mainer-Pardos, Demetrio Lozano, Jerónimo García-Romero

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Summary: The main aim of this study was to analyze the relationship between sole pattern parameters of football boots with the frequency of injuries that occur in semiprofessional and amateur footballers. The study sample was composed of 77 male football players. All were at least 18 years old, played at least 10 h per week, gave signed informed consent to take part and properly completed the Visual Analogue Scale. This study analysed data from each player's medical history, including age, injuries, years of practice, field type and surface condition information. The visual analogic score in semiprofessional players was higher (2.05 ± 2.43) than in amateur players (1.00 ± 1.1). A total of 141 lesions were collected, equivalent to 1.81 injuries for each football player studied (n = 77). The result of the ROC curve indicated that the player's years of practice could predict significantly (p &lt; 0.05) the presence of lower limb injuries, with an area under the curve of 0.714. This study described the predictive capacity of sole pattern characteristics concerning lower limb injuries in amateur and semiprofessional footballers. Football boot variables associated with the number of studs were associated with foot and ankle overload injuries.



#12 An After-School Football Session Transiently Improves Cognitive Function in Children

Reference: Int J Environ Res Public Health. 2022 Dec 22;20(1):164. doi: 10.3390/ijerph20010164.

Authors: Daniele Magistro, Simon B Cooper, Ruth Boat, Fabio Carlevaro, Francesca Magno, Cristian Castagno, Martina Simon, Giovanni Musella

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Summary: The aim of the present study was to evaluate the effect of a real-world after-school football session on subsequent cognitive function in primary school children. Following ethical approval, 100 children (aged 8-9 year) from the same after-school football club were randomly assigned to either an intervention (60 min football activity) or control (continued to rest) group. Cognitive function (selective visual attention, short term memory and long-term memory) was assessed prior to, immediately following and 45 min following the football session (and at the respective timepoints in the control group). Data were analysed via two-way (group * time) mixed methods ANOVA. The pattern of change in all domains of cognition over time, was different between the football and control groups (group * time, all p &lt; 0.001). Specifically, performance on all cognitive tasks was greater immediately following the football session in the intervention group compared to the control group (selective visual attention, p = 0.003; short-term memory, p = 0.004; long-term memory, p &lt; 0.001). However, there was no difference between the group 45 min following the football session (p = 0.132-0.393). These findings suggest that an after-school football session enhances cognition immediately post-activity in primary school children.



#13 Football-specific extension of the IOC consensus statement: methods for recording and reporting of epidemiological data on injury and illness in sport 2020

Reference: Br J Sports Med. 2023 Jan 6;bjsports-2022-106405.  doi: 10.1136/bjsports-2022-106405.

Authors: Markus Waldén, Margo Mountjoy, Alan McCall, Andreas Serner, Andrew Massey, Johannes L Tol, Roald Bahr, Michel D'Hooghe, Natália Bittencourt, Francesco Della Villa, Michiko Dohi, Gregory Dupont, Mark Fulcher, Dina Christina Christa Janse van Rensburg, Donna Lu, Thor Einar Andersen

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Summary: Several sports have published consensus statements on methods and reporting of epidemiological studies concerning injuries and illnesses with football (soccer) producing one of the first guidelines. This football-specific consensus statement was published in 2006 and required an update to align with scientific developments in the field. The International Olympic Committee (IOC) recently released a sports-generic consensus statement outlining methods for recording and reporting epidemiological data on injury and illness in sport and encouraged the development of sport-specific extensions.The Fédération Internationale de Football Association Medical Scientific Advisory Board established a panel of 16 football medicine and/or science experts, two players and one coach. With a foundation in the IOC consensus statement, the panel performed literature reviews on each included subtopic and performed two rounds of voting prior to and during a 2-day consensus meeting. The panel agreed on 40 of 75 pre-meeting and 21 of 44 meeting voting statements, respectively. The methodology and definitions presented in this comprehensive football-specific extension should ensure more consistent study designs, data collection procedures and use of nomenclature in future epidemiological studies of football injuries and illnesses regardless of setting. It should facilitate comparisons across studies and pooling of data.



#14 The effect of neuromuscular injury reduction programs which contain neck exercises on the incidence of soccer-related head and neck injuries

Reference: J Athl Train. 2023 Jan 16. doi: 10.4085/1062-6050-0340.22. Online ahead of print.

Authors: Kerry Peek, Theo Versteegh, Stella Veith, Matt Whalan, Suzi Edwards, Marnee J McKay, Andrew Gardner

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Summary: There is growing concern among soccer players, coaches and parents regarding head and neck injuries, including concussion, particularly from heading a ball. Thus, creating a need to explore soccer-specific head injury risk reduction initiatives. One such initiative is to condition the neck musculature of young players by adding neuromuscular neck exercises into existing injury reduction exercise programs. The aim was to investigate the effect of neuromuscular neck exercises completed as part of an injury risk reduction exercise program on the incidence of soccer-related head and neck injuries in adolescent (12-18 years) soccer players. Two sports high School and six soccer clubs participated in this study with a total of 364 male and female soccer players, aged 12-18 years. We targeted one sports high school and two soccer clubs who completed neuromuscular neck exercises contained within an injury reduction program during training (Neck Training Group) as well as another sports high school and four soccer clubs who completed an injury reduction program but without neck exercise (Comparison Group) during the 2021 soccer season. Self-reported injury data were collected from each player at the end of the season and used to calculate incidence rate ratios (IRR) with 95% confidence intervals (95%CI). In total, 364 players completed the study, including 146 players in the Neck Training Group and 218 players in the Comparison Group. Despite players in the Neck Training Group being less likely to self-report a concussion (incidence rate ratio (IRR): 0.23 (95%CI 0.03-1.04) and pain on heading a ball (IRR:0.62 (95%CI 0.34-1.07), only lower incidence of potential concussive events (IRR:0.38 (95%CI 0.14-0.90); p<0.05) was significant. Integrating neuromuscular neck exercises into injury reduction exercise programs has the potential to reduce the risk of sustaining a potential concussive event, concussion and/or pain on heading a ball in adolescent soccer players.



#15 Acute Effects of Kinesio Taping on Functional Performance in Healthy Soccer Players: A Randomized, Controlled Crossover Trial

Reference: J Funct Morphol Kinesiol. 2022 Dec 20;8(1):2. doi: 10.3390/jfmk8010002.

Authors: Giuseppe Annino, Anas Alashram, Cristian Romagnoli, Emanuele Balducci, Marco De Paolis, Vincenzo Manzi, Elvira Padua

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Summary: This study aimed to investigate the acute effects of the Kinesio tape (KT) application on functional performance in healthy athletes. In this randomized, controlled crossover trial, a total of sixteen healthy soccer players (male = 14; age = 23.28 ± 3.13 years old) were assigned randomly into either KT over quadriceps, KT over hamstring, KT over quadriceps plus hamstring, or no intervention control condition. Four conditions were applied in a crossover design through three consecutive test sessions for each condition with a washout period of 2 days between the trials. Afterwards, all participants performed a 5-min warm-up routine and four sets of 30-s static stretching exercises for the hamstring and gluteal muscles for three consecutive treatment sessions. The running, jump, and flexibility tests were used to assess the functional performance of healthy athletes. A total of sixteen participants completed the study. No significant differences in the jump, flexibility, and running tests among the conditions were reported (p &gt; 0.05). These findings suggest that KT application has no acute effects in improving functional performance in healthy athletes. However, further studies with larger sample sizes are needed to verify our results.



#16 The Assessment of Ankle Range-of-Motion and Its Relationship with Overall Muscle Strength in a Cross-Section of Soccer Players

Reference: Sports (Basel). 2023 Jan 5;11(1):12. doi: 10.3390/sports11010012.

Authors: Piergiorgio Francia, Carlo Ferri Marini, Leonardo Bocchi, Barbara Piccini, Giuseppe Seghieri, Ario Federici, Sonia Toni, Francesco Lucertini

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Summary: Soccer (football) practice can induce a limitation of ankle range of motion (ROM) that is a possible risk factor for injury and other negative consequences over time. The main objective of this research was to investigate the effects of soccer practice on ankle ROM throughout the entire period of a sports career of soccer players (SP). Furthermore, the relationship between ankle ROM and muscle strength in SP of different ages was studied. A total of 204 SP (range 6.7-45.1 years) and 87 controls (range: 7.5-45.2 years) matched for age, body mass index (BMI), and gender, were assessed. Ankle ROM in both plantar flexion (APF) and dorsiflexion (ADF) in addition to handgrip strength (HGS) were evaluated using an inclinometer and the Jamar hydraulic hand dynamometer, respectively. The comparison between SP and control groups showed a significant reduction in ankle ROM of both APF (26.3 ± 7.2° vs. 32.6 ± 7.4°; d = -0.90; p &lt; 0.001) and ADF (95.5 ± 15.6° vs. 105.5 ± 15.8°; d = -0.66; p &lt; 0.001). In SP, the results of the ANOVAs test indicate that age had a significant effect on ADF (F = 4.352, p = 0.038, partial eta-squared (ηp2) = 0.015) but not on APF (F = 0.430, p = 0.746, ηp2 = 0.001). Moreover, considering only the SP, a weak inverse correlation between ADF and HGS group ADF was found (rs = -0.27; p &lt; 0.001). Factors such as the non-linear trend of growth in young SP could hinder the definition of the relationship between ankle ROM, age, and muscle strength. However, the appropriate consideration of age and muscle strength could facilitate the management of ankle ROM in PF of different ages.



#17 Risk Factors for Symptomatic Bilateral Lumbar Bone Stress Injury in Adolescent Soccer Players: A Prospective Cohort Study

Reference: Am J Sports Med. 2023 Jan 20;3635465221146289. doi: 10.1177/03635465221146289.

Authors: Toshiharu Tsutsui, Satoshi Iizuka, Seira Takei, Toshihiro Maemichi, Suguru Torii

Summary: Lumbar bone stress injury (BSI) is a high-risk long time-loss injury for adolescent soccer players. However, the risk factors for lumbar BSI are unclear. The purpose was to identify the risk factors for bilateral lumbar BSI for adolescent soccer players. Adolescent soccer players underwent orthopaedic examination, whole-body dual energy x-ray scan, lumbar magnetic resonance imaging (MRI), and muscle tightness testing at baseline. Lumbar lordosis (LL), sacral slope, maturity stage of lumbar vertebral body, and bone marrow edema (BME) at the L5 were examined via MRI. In addition, bone mineral density and content; trunk lean body mass via dual energy x-ray scan; and bilateral muscle tightness including the iliopsoas, hamstrings, and quadriceps were measured. Lumbar BSI was diagnosed as positive bilateral BME and extension-based lumbar pain. All participants were examined twice, one at 6 months and one at 1 year, after the baseline examination. Multivariate logistic regression analysis was performed to identify the risk factors for bilateral lumbar BSI. A total of 69 (26.3%) players were diagnosed with bilateral lumbar BSI. Asymptomatic BME (odds ratio [OR], 4.260; 95% CI, 2.153-8.431), apophyseal stage of the lumbar vertebral body (OR, 3.438; 95% CI, 1.698-6.959), sacral slope relative to LL ≥5° (OR, 4.067; 95% CI, 2.021-8.181), and hamstring tightness ≥50° (OR, 3.221; 95% CI, 1.385-7.489) were significantly associated with bilateral lumbar BSI. The incidence of bilateral lumbar BSI was common at 26.2%. Asymptomatic BME, sacral anterior tilt relative to LL, immature lumbar epiphyses, and hamstring tightness were found to be risk factors for bilateral lumbar BSI. The results of this study suggest that regular MRI examination could facilitate the early detection of BME, and improvement in hamstring flexibility and lumbosacral alignment may prevent bilateral lumbar BSI in young athletes.



#18 Sports, football and dermatology

Reference: J Eur Acad Dermatol Venereol. 2023 Feb;37(2):217. doi: 10.1111/jdv.18836.

Authors: Johannes Ring

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