Latest research in football - week 36 - 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 Corrigendum: The relationship between locus of control and pre-competitive anxiety in highly trained soccer players

Reference: Front Psychol. 2023 Aug 21;14:1272127. doi: 10.3389/fpsyg.2023.1272127. eCollection 2023.

Authors: Imen Ben Amar, Chiraz Gomni, Oussama Gaied Chortane, Aymen Khemiri, Rania Ghouaiel, Julien S Baker

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#2 Adherence to the Mediterranean diet in young male soccer players

Reference: BMC Nutr. 2023 Sep 4;9(1):101. doi: 10.1186/s40795-023-00761-6.

Authors: César Leão, Sílvia Rocha-Rodrigues, Inês Machado, João Lemos, Sandra Leal, Hadi Nobari

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Summary: Nutrition is vital in health and sports performance by improving anthropometric-related parameters and dietary habits, especially in the youngest ages. The Mediterranean diet (MD) has been highly recognized for its positive health effects and low adverse environmental impact. We aimed to characterize adherence to the MD and analyze its association with anthropometric parameters in young soccer players. In the present study, 132 male young soccer players from under 9 to under 15 categories (aged 7 to 15 years) from a Portuguese football club participated. The Mediterranean Diet Quality Index for Children and Adolescents (KIDMED) questionnaire was applied to assess adherence to the MD. Anthropometric-related parameters, including body mass, height, triceps skinfold thickness (TSKF), suprailiac skinfold thickness (SISKF), body mass index (BMI) and body fat percentage (%BF), were determined. The differences between groups were performed accordingly to normal and non-normal distribution. Spearman's correlations were performed to analyze the hypothetical correlation between KIDMED and BMI. Players reached an average KIDMED score of 8.36 ± 1.92, showing that 68.2% (n = 90) reached high adherence to the MD, 31.1% (n = 41) had moderate adherence to the MD, and 0.78% (n = 1) had poor adherence to the MD. When the analysis was made for age group and BMI classification, no significant differences were observed in adherence to the MD. Considering the main characteristics of the MD, 50.8% consumed fruit (vs. 49,2%), 52.3% consumed vegetables (vs. 47,7%), and only 20% consumed oleaginous dried fruits (vs. 80%). Dairy consumption throughout the day was 49,2% (vs. no: 50,8%). Data from the present study showed that many soccer players adhered to the MD, and no differences were observed for age group or BMI classification.



#3 Financial burden of anterior cruciate ligament reconstructions in football (soccer) players: an Australian cost of injury study

Reference: Inj Prev. 2023 Sep 3;ip-2023-044885. doi: 10.1136/ip-2023-044885. Online ahead of print.

Authors: Andrew George Ross, Blaise Agresta, Marnee McKay, Evangelos Pappas, Tegan Cheng, Kerry Peek

Summary: The aim was to estimate the financial burden of anterior cruciate ligament (ACL) reconstructions in amateur football (soccer) players in Australia over a single year, including both direct and indirect cost. Available national direct and indirect cost data were applied to the annual incidence of ACL reconstructions in Australia. Age-adjusted and sex-adjusted total and mean costs (ACL and osteoarthritis (OA)) were calculated for amateur football (soccer) players in Australia using an incidence-based approach. The estimated cost of ACL reconstructions for amateur football players is $A69 623 211 with a mean total cost of $A34 079. The mean indirect costs are 19.8% higher than the mean direct costs. The mean indirect costs are lower in female (11.5%, $A28 628) and junior (15.3%, $A29 077) football players. The mean ACL costs are 3-4-fold greater than the mean OA costs ($A27 099 vs $A6450, respectively), remaining consistent when stratified by sex and age group. Our model suggests that for every 10% increase in adherence to injury prevention programmes, which equates to approximately 102 less ACL injuries per year, $A9 460 224 in ACL costs could be saved. While the number of ACL reconstructions per year among football players in Australia is relatively small, the annual financial burden is high. Our study suggests that if injury prevention exercises programmes are prioritised by stakeholders in football, significant cost-savings are possible.



#4 The relationship between deliberate practice, play, and futsal in childhood and adolescence and the development of different decision-making skills in professional female soccer players

Reference: Psychol Sport Exerc. 2023 Sep;68:102470. doi: 10.1016/j.psychsport.2023.102470. Epub 2023 Jun 12.

Authors: Guilherme Machado, Sixto González-Víllora, Israel Teoldo

Summary: Soccer players' ability to make efficient and quick decisions has gained more importance due to the increase in game speed in the last few years. Therefore, this study aimed to examine the relationship between the engagement in previous developmental activities in soccer and futsal with the quality and speed of decision-making skills in different phases of sport development of elite female soccer players. The sample comprised 77 elite Brazilian professional female soccer players. Players' decision-making skills were assessed based on an objective video-based test - TacticUP®. We used a retrospective questionnaire to collect information about previous participation in different developmental activities. The results showed that engagement in deliberate practice in soccer and futsal, especially during childhood and early adolescence, is related to a better quality of offensive decision-making skills, although showing small to medium effect sizes. We highlight that deliberate practice in futsal is associated only with offensive decision-making skills with the ball and near the ball. In turn, engaging in deliberate play in soccer, mainly in childhood and early adolescence, is related to quicker offensive and defensive decision-making skills, showing mostly medium effect sizes. To the best of our knowledge, it was the first study to measure the relationship of decision-making speed with developmental activities in soccer. It is concluded that deliberate practice in soccer and deliberate play in soccer are associated with different dimensions of decision-making skills.



#5 A random forest approach to explore how situational variables affect perceived exertion of elite youth soccer players

Reference: Psychol Sport Exerc. 2023 Jul;67:102429. doi: 10.1016/j.psychsport.2023.102429. Epub 2023 Mar 21.

Authors: Diego Marqués-Jiménez, Jaime Sampaio, Julio Calleja-González, Ibon Echeazarra

Summary: The aim of this study was to explore how situational variables affect youth soccer players' perceived exertion (RPE) after official matches. Thirty-five elite youth male players (14.33 ± 0.86 years; 173.49 ± 6.16 cm; 63.44 ± 5.98 kg) who belonged to two different teams of a professional club participated in this study. Data collection was conducted during two seasons (2016-2017, 2017-2018) and included 60 official matches (30 official matches per team). Ten minutes after each match players rated their RPE and using a modified Borg CR-10 scale. A Random Forest Regression was used to quantify the importance of match-related situational variables in RPE. Afterwards, a linear mixed model analysis was applied to identify the variability in RPE among the situational variables. The game-playing time, the player status (starter or substitute) and the player identity were the strongest predictors of RPE. Moreover, the match outcome and the final scoreline showed significant effects on both starter and substitute players but the main effect of the quality of the opponent was only identified in starter players (p < 0.05). These results allow practitioners to know how situational variables interact and modulate RPE after official matches and help them to prescribe and adapt the players' training content and load before and after matches.



#6 A developmental perspective on decision making in young soccer players: The role of executive functions

Reference: Psychol Sport Exerc. 2023 Mar;65:102362. doi: 10.1016/j.psychsport.2022.102362. Epub 2022 Dec 6.

Authors: Sinikka M Heisler, Babett H Lobinger, Lisa Musculus

Summary: Lately, interest in both domain-specific and domain-general cognitive processes has increased as a means to explain soccer player expertise. While the two types of processes have mostly been studied separately, we sought to connect these lines of research by investigating the role of executive functions in soccer players' decision making from a developmental perspective. As these cognitive processes as well as their relation might differ between age groups, we took a developmental perspective to better understand this link in a sample of N = 128 soccer players (Mage = 10.69 years, SD = 1.44). Two age groups (younger vs. older players) performed a video-based option-generation and decision-making task that used temporal occlusion. Additionally, executive functions were assessed with standardized computer-based tests. Results show a link between executive functions and sport-specific decision making, most prominent for working memory. Further, older players generated better options and showed better inhibition and cognitive flexibility than younger players. We suggest there is a crucial turning point in cognitive development around the age of 11 years.



#7 Gritting One's way to success - Grit explains skill in elite youth soccer players beyond (deliberate) practice

Reference: Psychol Sport Exerc. 2023 Jan;64:102328. doi: 10.1016/j.psychsport.2022.102328. Epub 2022 Oct 31.

Authors: Paul Larkin, Dijana Cocić, David T Hendry, A Mark Williams, Donna O'Connor, Merim Bilalić

Summary: Practice is one of the most important predictors of skill. To become an expert, performers must engage in practice for a prolonged time to develop the psychological characteristics necessary for outstanding performance. Deliberate practice (DP), that is focused repetitive activities with corrective feedback, is particularly beneficial for skill development. The amount of accumulated DP differentiates experts and novices. However, the predictive strength of DP weakens considerably when it comes to differentiating between differently skilled experts, leaving a way clear for other non-practice related factors to exercise their influence. In this paper, we demonstrate using a large sample (388) of elite youth soccer players that one such factor, the personality trait of grit, predicts expertise level both directly and indirectly. Grittier players accumulated more time in coach-led team practice, the activity, which is arguably closest to DP in team sports, which in turn predicted the skill level. Other practice activities, such as self-led training or playing with peers, were not predictive of skill level, neither were they influenced by grit. Grit, however, continued to exert a direct positive influence on the skill level of players even after accounting for the hours of DP accumulated. Overall, a standard deviation of change in the grit score resulted in at least a third of standard deviation improvement in skill. Our findings highlight the need for the inclusion of additional factors in theoretical frameworks in situations where the predictive power of traditional expertise factors, such as practice, is limited.



#8 The profiles of single leg countermovement jump kinetics and sprinting in female soccer athletes

Reference: Heliyon. 2023 Aug 19;9(8):e19159. doi: 10.1016/j.heliyon.2023.e19159. eCollection 2023 Aug.

Authors: Honghao Fu, Zhiyuan Li, Xiao Zhou, Jiaoqin Wang, Zhuo Chen, Guanrong Sun, Jingbo Sun, Hongtao Zeng, Laihong Wan, Yueying Hu, Feng Wang, Junyi Zheng

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Summary: The purposes were to evaluate kinetics in lower limbs using single leg countermovement jump (SLCMJ) and to identify the differences in SLCMJ kinetics between sprinting fast players and sprinting slow players in elite university female soccer players. Seventeen participants at the national tournament level completed the survey. SLCMJ and 30 m sprinting tests were performed. A force-plate was used to collect the data of the SLCMJ test. Significant differences of concentric maximum rate of force development (RFD), concentric RFD, concentric RFD/body weight (BW), peak net takeoff force/BW, peak power, and peak power/BW existed between both legs during the SLCMJ among all the participants. For further analysis, the participants were divided into fast group and slow group based on sprinting performance. Significant differences existed between the two groups in concentric peak velocity (nondominant, p = 0.028) and vertical velocity at takeoff (nondominant, p = 0.021). Concentric maximum RFD (p = 0.036) was significantly different between both legs in the slow group. Among elite university female soccer players, the players who presented more increased asymmetry of kinetic characteristics of jumping, also showed weak sprinting performance. Moreover, the players presented the best performance in velocity of the jumping variables and also had the best sprinting performance. Coaches and players should focus on keeping inter-limb balance and developing jumping velocity to improve sports performance. In future, the cause-and-effect relationship between jumping and sprinting should be identified.



#9 The Effects of Nitrate Supplementation on Performance as a Function of Habitual Dietary Intake of Nitrates: A Randomized Controlled Trial of Elite Football Players

Reference: Nutrients. 2023 Aug 25;15(17):3721. doi: 10.3390/nu15173721.

Authors: Matjaž Macuh, Nenad Kojić, Bojan Knap

Summary: Nitrates are an effective ergogenic supplement; however, the effects of nitrate supplements based on habitual dietary nitrate intake through diet alone are not well understood. We aimed to assess this in a group of 15 highly trained football players from Slovenian football's First Division. Participants underwent two separate Cooper performance tests either with nitrate supplementation (400 mg nitrates) or placebo while having their nutrition assessed for nitrate intake, as well as energy and macronutrient intake. Nitrate supplementation had a statistically significant positive effect on performance if baseline dietary nitrate intake was below 300 mg (p = 0.0104) in both the placebo and intervention groups. No effects of nitrate supplementation when baseline dietary nitrate intake was higher than 300 mg in the placebo group could be concluded due to the small sample size. Nitrate supplementation did not have a significant effect on perceived exertion. The daily nitrate intake of the participants was measured at 165 mg, with the majority of nitrates coming from nitrate-rich vegetables.



#10 Epidemiology of Injuries in Men's Professional and Amateur Football (Part I)

Reference: J Clin Med. 2023 Aug 26;12(17):5569. doi: 10.3390/jcm12175569.

Authors: Tudor Vladimir Gurau, Gabriela Gurau, Doina Carina Voinescu, Lucretia Anghel, Gelu Onose, Daniel Andrei Iordan, Constantin Munteanu, Ilie Onu, Carmina Liana Musat

Summary: Football is the most popular sport among men, associated with a certain risk of injury, which leads to short- and long-term health consequences. While the injury profile of professional footballers is known, little is known about the injury profile of amateur footballers; amateur football is a major and diverse area, the development of which should be a priority for football associations around the world and UEFA. The aim of this study was to perform a systematic review of epidemiological literature data on injuries in professional and amateur football players belonging to certain leagues. A systematic review according to the PRISMA guidelines was performed until June 2023 in the databases PubMed, Web of Science, Google Academic, Google Scholar, and Diva portal. Forty-six studies reporting injury incidence in professional and amateur men's football were selected and analyzed. Two reviewers independently extracted data and assessed study quality using an adapted version of the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement and the Newcastle Ottawa Scale (NOS) to assess risk of bias for the quality of external validity. The overall incidence of injuries in professional male football players was 7.75 ± 2.28, 95% confidence interval, injuries/1000 h of exposure and that of amateur football players was 7.98 ± 2.95, 95% confidence interval, injuries/1000 h of exposure. The incidence of match injuries (30.64 ± 10.28, 95% confidence interval, injuries/1000 exposure hours) was 7.71 times higher than the training injury incidence rate (3.97 ± 1.35, 95% confidence interval, injuries/1000 h) in professional football players and 5.45 times higher in amateurs (17.56 ± 6.15 vs. 3.22 ± 1.4, 95% confidence interval, injuries/1000 h). Aggregate lower extremity injuries had the highest prevalence in both categories of footballers, being 83.32 ± 4.85% in professional footballers and 80.4 ± 7.04% in amateur footballers: thigh, ankle, and knee injuries predominated. Professional and amateur football players are at substantial risk of injury, especially during matches that require the highest level of performance. Injury rates have implications for players, coaches, and sports medicine practitioners. Therefore, information on football injuries can help develop personalized injury risk mitigation strategies that could make football safer for both categories of football players. The current findings have implications for the management, monitoring, and design of training, competition, injury prevention, especially severe injury, and education programs for amateur football players.



#11 Football players with hip dysplasia: The relationship between muscle strength, functional performance, self-reported sport and recreation, cartilage defects and sex. A cross-sectional study

Reference: J Orthop Sports Phys Ther. 2023 Sep 8;1-24. doi: 10.2519/jospt.2023.12026. Online ahead of print.

Authors: Michael J M O'Brien, Joanne L Kemp, Adam Ivan Semciw, Inger Mechlenburg, Julie S Jacobsen, Matthew G King, Mark J Scholes, Peter R Lawrenson, Kay Crossley, Rintje Agricola, Richard B Souza, Joshua Heerey

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Summary: In symptomatic football players with hip dysplasia, we aimed to explore the relationships between self-reported sport and recreation ability and (i) hip muscle strength, (ii) functional performance, and investigate if these relationships were modified by sex or cartilage defects. In this cross-sectional study, (n=50) football players with longstanding (>6 months) hip and/or groin pain, a positive flexion/adduction/internal rotation (FADIR) test and a lateral-centre-edge angle <250 were included. Hip muscle strength and functional performance were assessed. Self-reported sport and recreation ability was quantified using the sports and recreational subscales from the International Hip Outcome Tool-33 (iHOT-Sport) and the Copenhagen Hip and Groin Outcome Score (HAGOS-Sport). Relationships were evaluated using regression models with sex and cartilage defects as potential effect modifiers. There was a positive linear relationship between the one-leg-rise test and the iHOT-Sport subscale (β 0.61; 95% CI: 0.09 to 1.14). A polynomial (concave) relationship was found between peak eccentric adduction strength and the HAGOS-Sport subscale (β -30.88; 95% CI: -57.78 to -3.99). Cartilage defects modifed the relationship between peak isometric adduction strength and HAGOS-Sport, with those with cartilage.



#12 An intelligent data analysis-based medical management method for lower limb health of football athletes

Reference: Math Biosci Eng. 2023 Jun 21;20(8):14005-14022. doi: 10.3934/mbe.2023624.

Authors: Xiang Wang, Yongcheng Wang, Limin He

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Summary: With increasingly mature commercial operations, football has become the most popular sport in the world. As the main body of football, athletes are prone to injury due to an increasing degree of competition intensity. Their health determines the length of these athletes careers, especially regarding the lower limbs that are mainly used. Therefore, the smart visualization approaches that can realize such function are in urgent demand in the area of sports healthcare. Benefitted by the strong ability of perception and analysis, a convolutional neural network (CNN) is utilized to construct an intelligent data analysis-based medical management method for the lower limb health of football athletes. First, the CNN is formulated as the main backbone, and its parameters are optimized for multiple rounds during the training stage. Then, a statistical analysis software named SPSS is introduced to assess the effect mechanism of different postures on lower limbs. Some experiments are carried out on simulative data to evaluate the proposed method, and results show a good performance of the proposed method.



#13 The effects of high-velocity hamstring muscle training on injury prevention in football players

Reference: Front Physiol. 2023 Aug 21;14:1219087. doi: 10.3389/fphys.2023.1219087. eCollection 2023.

Authors: Sigitas Kamandulis, Joan Aureli Cadefau, Audrius Snieckus, Mantas Mickevicius, Inga Lukonaitiene, Pornpimol Muanjai, Danguole Satkunskiene, Victor Molina, Xavier de Blas Foix, Daniele Conte

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Summary: Explosive and fast body movements, sprints, jumps and quick changes of direction, which are characteristic of the football training, place considerable strain on the hamstring muscles. Due to the high occurrence of hamstring injuries, new preventive strategies are required that focus on high-velocity training. The purpose was to assess the effectiveness of high-velocity elastic-band training in reducing the occurrence of hamstring injuries in football players. Male football players from 15 teams (n = 319) playing in national competitions participated in this study. The players were involved in a 5-week exercise period in either the intervention group (INT) or the control group (CON), with a follow-up period of ∼4 months where hamstring injuries and exposure time were recorded. The INT group had two to three sessions per week of elastic-band training with low-load, high-velocity leg curls while lying prone; the CON group performed self-paced football-specific drills. The incidence rate of hamstring injuries was 6.5% in the INT group (8 out of 123 players) and 9.2% in the CON group (18 out of 196 players). Although the INT group showed almost 1/3 reduction in hamstring injury incidence compared to the CON group, the difference was not statistically significant (p > 0.05). Moreover, no differences (p > 0.05, odds ratio [OR] = trivial-to-small) in distribution between the groups were found in hamstring injury characteristics (leg dominance and mechanism) except for the distribution of injuries that occurred during matches or training (p = 0.036; OR = 6.14, moderate). The program of high-velocity elastic-band training did not prove to be effective in preventing hamstring muscle injuries in football players despite displaying some positive indications that could be considering when creating injury prevention programs.



#14 Comparative Risk Analysis of Low Back Pain among Professional Football, Ice Hockey, and Floorball Athletes

Reference: Med Sci Monit. 2023 Sep 6;29:e941386. doi: 10.12659/MSM.941386.

Authors: Magdaléna Hagovská, Alena Buková, Peter Takáč, Viliam Knap, Perla Ondová, Katarína Oravcová, Anna Kubincová

Summary: Low back pain (LBP) is a common concern among professional athletes, potentially hindering performance and career longevity. However, comparative assessments of LBP prevalence and severity across various sports remain scarce. This study aimed to evaluate the factors associated with LBP in 388 professional athletes, including football, ice hockey, and floorball players. Conducted from June 2021 to September 2022, this cross-sectional study incorporated 388 athletes from national elite clubs, including football (n=148), ice hockey (n=179), and floorball (n=61). The Oswestry Disability Index (ODI), comprising sections like pain intensity, self-care, lifting, walking, sitting, standing, sleeping, sexual life, social life, and traveling, was employed to evaluate spinal pain and disability. The study found no significant disparities in the LBP assessment among the groups. The relative risk (OR) of LBP and disability varied among the sports: football players displayed a lower risk (OR=0.49; 95% CI 0.32-0.74, P≤0.001), while ice hockey players had a higher risk (OR=2.18; 95% CI 1.45-3.29, P≤0.001) compared to the others. In contrast, the risk for floorball players (OR=0.82; 95% CI 0.47-1.41) did not significantly deviate from that of the other two sports. LBP prevalence stood at 42.6% for football players, 60.1% for ice hockey players, and 49.2% for floorball players. Among these, ice hockey players exhibited a 2.18-fold increased risk of developing LBP and associated disability when compared to their football and floorball counterparts.



#15 Radiographic assessment of the pubic symphysis in elite male adolescent football players: Development and reliability of the Maturing Adolescent Pubic Symphysis (MAPS) classification

Reference: Eur J Radiol. 2023 Aug 28;167:111068. doi: 10.1016/j.ejrad.2023.111068. Online ahead of print.

Authors: Astrid van Ovost, David Frederikus Hanff, Andreas Serner, Pim van Klij, Rintje Agricola, Adam Weir

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Summary: The pubic symphysis is susceptible to growth related injuries long after the adolescent growth spurt. Our study describes the radiographic maturation of the pubic symphysis on pelvic radiographs in adolescent football players and introduces the Maturing Adolescent Pubic Symphysis classification (MAPS classification). Anteroposterior pelvic radiographs of 105 healthy adolescent male football players between 12 and 24 years old were used to develop the classification system. The radiological scoring of the symphyseal joint was developed over five rounds. The final MAPS classification items were scored in random order by two experienced readers, blinded to the age of the participant and to each other's scoring. The inter- and intra-rater reliability were examined using weighted kappa (κ). We developed a classification system with descriptive definitions and an accompanying pictorial atlas. The symphyseal joint was divided into three regions: the superior corners, and the upper and lower regions of the joint line. Inter-rater reliability was substantial to almost perfect: superior region: κ = 0.70 (95% CI 0.60---0.79), upper region of the joint line: κ = 0.89 (95% CI 0.86---0.92), lower region of the joint line: κ = 0.65 (95% CI 0.55---0.75). The intra-observer reliability showed similar results. The Maturing Adolescent Pubic Symphysis classification (MAPS classification) is a reliable descriptive classification of the radiographic maturation of the pubic symphysis joint in athletic males. The stages can provide a basis for understanding in clinical practice and will allow future research in this field.



#16 Examining the effect of task constraints on the emergence of creative action in young elite football players by using a method combining expert judgement and frequency count

Reference: Psychol Sport Exerc. 2023 Nov;69:102502. doi: 10.1016/j.psychsport.2023.102502. Epub 2023 Aug 3.

Authors: Tom de Joode, John van der Kamp, Geert J P Savelsbergh

Summary: In adult football, small-sided games are associated with increased action variability and suggested to promote more creative actions compared to regular 11v11 formats. This aligns with predictions from an ecological approach to perception and action that creative actions emerge in environments that grant variability in action, instead of being an expression of the individual player's ability to generate ideas. To further evidence for this prediction, the current study aimed to expand this observation to elite youth football players. To this end, the number of different and creative actions in 4v4 small-sided game and a 11v11 regular-sided game among 10- to 12-year-old elite football players were examined. We analyzed a total of 7922 actions, which were categorized for type and creativity. Based on a subset of these actions, a panel of elite football coaches judged action types occurring below 0.5% as significantly more creative than more frequent action types. Hence, we used an occurrence of 0.5% as threshold to distinguish creative actions from non-creative actions. The results showed that the total number of actions, the number of different action types, the number creative actions and the number of different creative action types was significantly higher for the small-sided game format than the regular-sided game. In conclusion, this study confirms that in elite youth football, small-sided games induce a more variable and creative action repertoire. This shows that practitioners can design learning environments that promote the emergence of creative actions.



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