Footballscience.net
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 "Football and Nutrition for Health" program on body composition, physical fitness, eating behaviours, nutritional knowledge, and psychological status among 7 to 10 years school children
Reference: Front Pediatr. 2023 Nov 8:11:1251053. doi: 10.3389/fped.2023.1251053. eCollection 2023.
Authors: Micaela C Morgado, Mónica Sousa, André B Coelho, Susana Vale, Júlio A Costa, André Seabra
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10663241/pdf/fped-11-1251053.pdf
Summary: Noncommunicable diseases and obesity are between the major health threat due to consumption of unhealthy foods and limited time spent on physical activities, a situation of particular concern among children. Since children spend most of their time at school, this study intends to investigate the effect of a school intervention program, which combines recreational football and nutrition education, on body composition, physical fitness, physical activity, blood pressure and heart rate, eating behaviours, nutritional knowledge, and psychological status in elementary school children. A total of 67 children, between 7 and 10 years old, were allocated into three groups: the Football Group (FG) which held 2 weekly sessions of 60 min of recreational football, the Nutrition and Football Group (NFG) which held 2 sessions per week of 60 min of recreational football plus 60 min of nutritional education and the Control Group (CG) which maintained its usual curriculum. The intervention lasted 12 weeks. All measurements were collected before and after the intervention. Intervention groups significantly (p < 0.05) improved BMI Z-score, rest heart rate, horizontal jump and shuttle test, physical activity level, and psychosocial health. The NFG group significantly decreased (p < 0.05) waist-to-height ratio and blood pressure, and significantly increased (p < 0.05) nutritional knowledge, fruit, and fish consumption. While FG significantly decreased (p < 0.05) the percentage of fat mass and significantly increased (p < 0.05) muscle mass and performance in the 20 m sprint. The results have shown to improve nutritional status, explosive strength, aerobic and neuromuscular fitness, as well as increase the level of physical activity. The nutritional education sessions contributed to increase nutritional knowledge and to improve the consumption of healthy food groups in a ludic-educational way. The "Football and Nutrition for Health" program was able to induce short-term improvements in several health markers, highlighting the role of the school curriculum in children's health.
#2 Equations for smartphone prediction of adiposity and appendicular lean mass in youth soccer players
Reference: Sci Rep. 2023 Nov 25;13(1):20734. doi: 10.1038/s41598-023-48055-y.
Authors: Marco A Minetto, Angelo Pietrobelli, Andrea Ferraris, Chiara Busso, Massimo Magistrali, Chiara Vignati, Breck Sieglinger, David Bruner, John A Shepherd, Steven B Heymsfield
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10676389/pdf/41598_2023_Article_48055.pdf
Summary: Digital anthropometry by three-dimensional optical imaging systems and smartphones has recently been shown to provide non-invasive, precise, and accurate anthropometric and body composition measurements. To our knowledge, no previous study performed smartphone-based digital anthropometric assessments in young athletes. The aim of this study was to investigate the reproducibly and validity of smartphone-based estimation of anthropometric and body composition parameters in youth soccer players. A convenience sample of 124 male players and 69 female players (median ages of 16.2 and 15.5 years, respectively) was recruited. Measurements of body weight and height, one whole-body Dual-Energy X-ray Absorptiometry (DXA) scan, and acquisition of optical images (performed in duplicate by the Mobile Fit app to obtain two avatars for each player) were performed. The reproducibility analysis showed percent standard error of measurement values < 10% for all anthropometric and body composition measurements, thus indicating high agreement between the measurements obtained for the two avatars. Mobile Fit app overestimated the body fat percentage with respect to DXA (average overestimation of + 3.7% in males and + 4.6% in females), while it underestimated the total lean mass (- 2.6 kg in males and - 2.5 kg in females) and the appendicular lean mass (- 10.5 kg in males and - 5.5 kg in females). Using data of the soccer players, we reparameterized the equations previously proposed to estimate the body fat percentage and the appendicular lean mass and we obtained new equations that can be used in youth athletes for body composition assessment through conventional anthropometrics-based prediction models.
#3 Psychology research in women's soccer: a scoping review
Reference: Sci Med Footb. 2023 Nov 27. doi: 10.1080/24733938.2023.2285962. Online ahead of print.
Authors: N Viktor Gredin, Katrine Okholm Kryger, Alan Mc Call, Bård E Solstad, Monica K Torstveit, Andrew Massey, Andreas Ivarsson
Summary: Previous research suggests that psychological factors play an important role in trying to explain and predict the participation, performance, and health of player and practitioners in soccer. However, most previous works have focused on specific research questions and included samples from male populations. As part of a larger Fédération Internationale de Football Association (FIFA) project aiming to steer women's soccer research, our purpose with this scoping review was to give an overview of the current state of psychology-related research within women's soccer. We searched five electronic databases up to April 2023, from which 280 original peer-reviewed articles met the inclusion criteria. Included records were inductively coded into 75 specific research topics and nine broader research categories. Population characteristics within each topic and category, and overall publication trends, were identified. The results revealed a growth in research attention, with notable increases in publication rates around the international competitions years, over the last two decades. While a notable number of abstracts did not report sufficient details about population age and/or playing levels, senior elite players were identified as the most common population studied. Most studies examined several topics from different research categories, with research focusing on emotions, moods and/or environmental factors, and the specific the topics of anxiety, stress, and coach behavior, receiving most research attention. Our study provides an informative mapping of all psychology-related research activity within women's soccer, which will enhance researchers' understanding of the current quantity of literature within this complex, heterogeneous, and growing area of research.
#4 Effects of exchange vs. controlled diet on biochemical, body composition and functional parameters in elite female soccer players
Reference: PLoS One. 2023 Nov 27;18(11):e0289114. doi: 10.1371/journal.pone.0289114. eCollection 2023.
Authors: Sandra Antón San Atanasio, Sergio Maroto-Izquierdo, Silvia Sedano
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10681300/pdf/pone.0289114.pdf
Summary: Due to the increasing level of professionalism, the high frequency of competitions, and the alarming injury rate observed in elite female soccer players, multidisciplinary strategies, including nutritional monitoring, need to be implemented. This study aimed to quantify energy, macronutrient and micronutrient intakes during the competitive period and to analyze the effects of two different nutritional interventions on nutritional knowledge, anthropometric data, biochemical values and physical performance. 19 elite female soccer players were randomly divided into two groups: the controlled-diet group (CG, n = 10), that followed a diet based on pre-established menus, and the exchange-diet group (EG, n = 9), that designed their own menus with an exchanged list. A cross-sectional study was designed to evaluate the dietary intake, while an experimental randomized controlled trial was designed to compare the effects of both 12-week nutritional interventions. Total energy, CHO, PROT, fibre and micronutrients intakes were below the general recommendations for athletes while, total and saturated fat intakes were above these. Moreover, there were no differences in diet during weekdays, pre-competition and competition days. The study also revealed a low nutritional knowledge and exchanged diet has demonstrated to be a better strategy to improve this. Biochemical monitoring showed that participants presented decreased concentration of haemoglobin and controlled diet may lead to greater effects on haemoglobin concentration and in anemia prevention. Both EG and CG showed significant reduction on skinfolds sum after intervention, but no significant differences were observed in thigh and calf indices. However, no significant changes were observed in soccer-related skills for any group.
#5 Within-Subject Principal Component Analysis of External Training Load and Intensity Measures in Youth Soccer Training
Reference: J Strength Cond Res. 2023 Dec 1;37(12):2411-2416. doi: 10.1519/JSC.0000000000004545.
Authors: Jakub Marynowicz, Mateusz Lango, Damian Horna, Karol Kikut, Marek Konefał, Paweł Chmura, Marcin Andrzejewski
Summary: The aim of this study was to identify which combination of external training load (EL) and external intensity (EI) metrics during youth soccer training sessions captured similar or unique information. Data were collected from 18 youth soccer players during an 18-week in-season competition period using a 10-Hz global positioning system, rating of perceived exertion (RPE), and session-RPE (sRPE). External training load measures included total distance (TD, in meters), PlayerLoad (PL, in arbitrary units), high-speed running distance (HSR, in meters), and number of accelerations (ACC, n). All EL metrics were also divided by session duration (minutes) to obtain EI values. A total of 804 training observations were undertaken (43 ± 17 sessions per player). The analysis was performed by use of the principal component analysis technique. The first principal component (PC) captured 49-70% and 68-89% of the total variance in EI and EL, respectively. The findings show that from the 5 EI metrics, most of the information can be explained by either TD per minute or PL per minute, with a loading from 0.87 to 0.98 and from 0.76 to 0.95, respectively. The majority of EL information can be explained by PL (loading: 0.93-0.98), TD (loading: 0.95-0.99), ACC (loading: 0.71-0.91), or sRPE (loading: 0.70-0.93). The second PC for EL metrics is most strongly correlated with HSR, with loadings from 0.53 to 0.84. The results suggest that the majority of the information contained in the EL variables can be captured in 1 PC without losing much information. The findings suggest that stakeholders who intend to provide a fast and holistic view of EL information in a daily training environment should report TD, PL, ACC, or sRPE plus HSR to coaching staff as a metrics that provides additional unique information.
#6 How Subtalar Kinematics Affects Knee Laxity in Soccer Players After Anterior Cruciate Ligament Injury?
Reference: Cureus. 2023 Oct 28;15(10):e47850. doi: 10.7759/cureus.47850. eCollection 2023 Oct.
Authors: Georgios Kakavas, Nikolaos G Malliaropoulos, Florian Forelli, Jean Mazeas, George Skarpas, Nicola Maffuli
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10679957/pdf/cureus-0015-00000047850.pdf
Summary: Purpose The goal of the current study was to ascertain whether there is an association between foot pronation and anterior cruciate ligament (ACL) injury in a group of elite professional soccer players. Methods Two groups of soccer players were studied, all of whom played in the Greek Super League. The ACL group included players who had suffered an ACL injury in the last 2 years. The non-ACL group was composed of players who had never suffered an ACL injury. We used a 3D baropodometric laser scanner to measure pronation or overpronation (navicular drop phenomenon) of the subtalar joint and how this affects the subtalar joint while standing. We assessed ACL laxity using the Genourob Rotab. Results ACL-injured patients, regardless of the mechanism of injury, exhibited greater navicular drop values than a randomly selected group of subjects with no history of ACL injury. Conclusion Greater knee joint laxity and subtalar pronation may be associated with an increased risk of ACL injury. Pronation of the foot appears to be a risk factor for ACL injury. These findings should be integrated into future studies to better define how neuromuscular control related to lower extremity biomechanics is associated with ACL injury.
#7 The relationships between relative age effect, personality constructs and achievement level in soccer
Reference: Front Sports Act Living. 2023 Nov 10:5:1226599. doi: 10.3389/fspor.2023.1226599. eCollection 2023.
Authors: Sofie Bolckmans, Kris Perquy, Janet L Starkes, Daniel Memmert, Werner F Helsen
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10667700/pdf/fspor-05-1226599.pdf
Summary: Youth soccer academies are challenged with the constant recruitment process of young talented players to select those who will achieve long-term success as an athlete. Youth soccer academies strive to enhance the physical and technical skill development as well as personality development of talented players because psychological characteristics play a crucial role in players' future success in their transition to professional soccer. The least mature players and relatively young players may have a greater need to possess superior technical/tactical or psycho-behavioral skills than those relatively older counterparts because of the higher selection rates of early maturing players. Due to RAEs, a significant decrease in the overall quality of professional soccer teams might be observed because of the loss of talent of physically smaller, but psychologically stronger and more versatile relatively young players who possess proper technical and tactical attributes at an early age. The first objective of this study was to examine any possible relationship between RAE and personality constructs. A second objective was to identify factors and effects that can help in the further improvement of talent selection and equal opportunities for elite youth soccer players based on their underlying RAE. The third objective was to consider the impact of RAE on long-term career development. In this retrospective observational study, 151 elite youth soccer players between 15 and 18 years of age were first grouped in birth quartiles. Personality constructs were then assessed, using a combination of observations, interviews, and a self-assessment questionnaire. Next competition level after 8 years was evaluated to identify RAEs, differences in personality characteristics and opportunities to reach professional soccer player status between relatively older vs. younger players. A clear significant RAE was observed for the whole database (Q1 = 38.4% vs. Q4 = 13.9%) with OR of 2.61 (χ2 = 19.46, p < 0.01, r = -0.85). Relatively young players had higher median scores on personality constructs such as self-confidence (p = 0.04), while relatively old players had higher median scores on personality constructs such as team orientation (p = 0.03). In the long term, more players of the youngest birth quartile were signed as professional players (76.2%), compared with relatively old players (46.6%). 65.0% of the 20 players had the highest total score on personality constructs developed as a professional soccer player, vs. 35.0% of the 20 players with the lowest scores. In conclusion, this study showed not only further evidence of the RAE but also provided evidence supporting "the underdog hypothesis" in national elite youth teams. Relatively young players were also more likely to get higher value senior professional contracts in the long term. We propose that this may be due to the relatively young players developing superior psychological skills and technical expertise to compensate for their early physical disadvantage. This in turn suggests the need for greater awareness of the importance of personality constructs in the future development of youth elite soccer players. Therefore, the crux of the issue is how youth soccer academies elicit the "best of both worlds" ie. moderating RAE whilst also gaining the benefits of the underdog hypothesis by creating the right environment for every player to develop to their full potential in elite youth soccer academies.
#8 Corrigendum: High-speed running and sprinting in professional adult soccer: current thresholds definition, match demands and training strategies. A systematic review
Reference: Front Sports Act Living. 2023 Nov 6:5:1323440. doi: 10.3389/fspor.2023.1323440. eCollection 2023.
Authors: Antonio Gualtieri, Ermanno Rampinini, Antonio Dello Iacono, Marco Beato
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10662963/pdf/fspor-05-1323440.pdf
#9 Children can rate perceived effort but do not follow intensity instructions during soccer training
Reference: Front Sports Act Living. 2023 Nov 2:5:1251585. doi: 10.3389/fspor.2023.1251585. eCollection 2023.
Authors: Marco Reinke, Gerd Schmitz
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10652393/pdf/fspor-05-1251585.pdf
Summary: The perception of effort is elementary for the self-regulation of exercise intensity in sports. The competence for rating perceived effort (RPE) seems to be related to physical and cognitive development. Children accurately rate perceived effort during incremental exercise tests when loads progressively increase, but it remains unclear how children perform when they participate in sports games, which are characterized by complex tasks with varying intensity profiles. The present study investigates children's competencies for rating perceived effort and producing predetermined intensities during soccer training. Twenty-five children aged 11-13 years performed two similar training sessions. In the first session, the children trained without intensity instructions and continuously rated their effort. In the second session, the children were instructed to produce predefined intensities. Before the first training session, executive functions were assessed by cognitive performance tests and a self-report measure. RPE correlated significantly with heart rate measures (R2 = 0.27, p < 0.001). As confirmed by factor analysis, individual differences in these correlations were related to the outcomes of the cognitive tests and the self-report measure. RPE in training session 2 differed from RPE in training session 1 (d = 1.22, p < 0.001), although the heart rate data did not differ significantly between training sessions (d = -0.19, p = 0.780). Thirteen-year-old children performed significantly better than eleven-year-old children (d = 1.69, p = 0.027). The results suggest that children are able to rate perceived effort during soccer training and that this ability is related to executive functions. Conversely, children may not be able to alter their intensities in response to instructions, although their ratings suggest that they have largely succeeded in doing so.
#10 Reference values for body composition and physical fitness of young Brazilian elite soccer players
Reference: Front Physiol. 2023 Nov 2:14:1285952. doi: 10.3389/fphys.2023.1285952. eCollection 2023.
Authors: Daniel Leite Portella, Ruben Vidal-Espinoza, Jose Sulla-Torres, Luis Felipe Castelli Correia de Campos, Rossana Gomez-Campos, Marco Cossio-Bolaños
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10652792/pdf/fphys-14-1285952.pdf
Summary: The aim was to a) to verify whether body composition and physical fitness should be analyzed by chronological age and/or maturity stage in young Brazilian soccer players and b) to propose reference values for the evaluation of body composition and physical fitness by maturity stage in elite soccer players. A descriptive-correlational study was carried out in 206 young Brazilian soccer players (11-16 years old). The sample selection was non-probabilistic by convenience. Weight and standing height were evaluated. Body composition (BC) was assessed by dual X-ray absorptiometry (DXA). BC indicators [(percent fat (%F), Fat-free mass (FFM), Fat mass (FM) and Bone mass (BM)] were extracted. For physical fitness (PF), we applied the Flexibility (cm) sit and reach tests, explosive strength tests [Counter Movement Jump CMJ (cm) and horizontal jump HJ (cm)], speed [Speed 10, 20, 30 and 40 m (seconds)] and Yo-Yo endurance level I test. Percentiles were constructed for BC and PF using the LMS method [L (Lambda; skewness), M (Mu; median) and S (Sigma; coefficient of variation)]. The explanatory power between chronological age (CA) with BC was: FM (R2 = 0.03%), FFM (R 2 = 0.66%) and BM (R 2 = 0.62%), while between maturity status (MS) with BC were: FM (R 2 = 0.04%), FFM (R 2 = 0.71%) and BM (R 2 = 0.66). The explanatory power between the CA with the physical fitness tests ranged from: (R 2 = 0.22-0.62%). While between MS with physical fitness the values ranged from: (R 2 = 0.23-0.64%). Percentiles per MS (P3, P5, P10, P15, P25, P50, P75, P85, P90, P95 and P97) were proposed for both BC and PF. The results of the study have shown that the evaluation of BC and PF of young soccer players should be performed by controlling for MS rather than for CA. The inclusion of a non-invasive method to control MS by means of percentiles during puberty may contribute to the development of retention and exclusion of young soccer players, thus, they may have a better chance of achieving sporting success.
#11 Internal and external load during on-field training drills with an aim of improving the physical performance of players in professional soccer: a retrospective observational study
Reference: Front Physiol. 2023 Nov 7:14:1212573. doi: 10.3389/fphys.2023.1212573. eCollection 2023.
Authors: Linda Ammann, Paweł Chmura
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10661947/pdf/fphys-14-1212573.pdf
Summary: Extensive research has led to evidence-based methodological recommendations for appropriate prescription and implementation of different training drills to improve the physical performance of professional soccer players, while also pointing out limitations of drills. Less is known about the current methods used in an ecological context and the extent to which evidence-based considerations are applied. Knowledge of current practices might also enable to identify pitfalls in successful implementation and/or deficiencies in the communication of scientific knowledge. Thus, the aim of this study was to quantify and compare the load that players experience in an ecological context during drills that are frequently used, and in which there is an intention to improve the players' physical capacities. Therefore, a retrospective observational cohort study was conducted over a 14-month period, analyzing 9 load measures during training drills of 39 players of a team competing in the highest Swiss league. The load experienced by players was statistically significant different between the assessed drill categories for each load measure (all p < .001). This indicates different drills provide different stimuli. HIIT drills proved to be a more powerful tool of getting players to cover distances at high-speed and to spend time at an intensity ≥90% HRmax compared to sided games. The sprint distance of players was very low in all sided games and in most cases also in HIIT drills, in the latter the players also hardly performed any deceleration. In small goal-oriented sided games, players covered a greater distance per minute when outside floaters were present. Particularly regarding an improvement of the players' aerobic capacity, the present data emphasize the relevance for coaches to ensure an appropriate exposure. In general, the importance of individual load management in professional soccer is highlighted.
#12 Age of Adolescent Female Soccer Players at First Ankle Sprain and Menarche
Reference: Prog Rehabil Med. 2023 Nov 29:8:20230042. doi: 10.2490/prm.20230042. eCollection 2023.
Authors: Yuri Inoue, Akihiro Tamura, Shogo Misu
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10682156/pdf/prm-8-20230042.pdf
Summary: The purpose was to provide targeted interventions for the prevention of first ankle sprains, this study determined the prevalence of ankle sprains in female adolescent soccer players and analyzed the correlation between the age at the first occurrence of ankle sprain and the age at menarche. The study included 131 female participants from three club teams. The mean age was 13.37 ± 0.96 years. A survey was conducted using a questionnaire that requested information regarding the age at which the first ankle sprain occurred, age at menarche, status of ankle problems, extent to which the ankle joint problem affected playing ability, use of medical facilities or other healthcare facilities for the first or recurrent ankle sprains, and methods used to care for their ankle. Ankle sprains most commonly occurred for the first time at 12 years, followed by the ages of 13, 10, and 11 years. About 25% of participants experienced their first ankle sprain at the age of menarche, 20% at 1 year after menarche, and 16% a year before menarche. The incidence of the first ankle sprain was high in the second and fifth years after starting to play soccer. Medical treatment was rarely received for the second or subsequent injury, although 36% had some sequelae. Adolescent female soccer players were not injured early in their soccer careers. Most players experienced their first ankle sprain at the age of 12 years, which was at or close to the age of menarche.
#13 Neuromuscular and perceptual-cognitive response to 4v4 small-sided game in youth soccer players
Reference: Front Physiol. 2023 Nov 9:14:1260096. doi: 10.3389/fphys.2023.1260096. eCollection 2023.
Authors: Filip Skala, Erika Zemková
Summary: The physical and psychological load of small-sided games (SSGs) can affect players' neuromuscular and cognitive functions. Yet, little is known about the acute performance changes after such a specific exercise in young soccer players and their association with exercise load applied. This study investigates i) the neuromuscular and perceptual-cognitive response to the SSG exercise load, and ii) the relationship between pre- and post-SSG changes in variables of performance and the respective exercise load in youth soccer players. Sixteen participants (13.6 ± 0.5 years) underwent a 30-min SSG 4v4 + GK protocol. Prior to and after the SSG they performed countermovement jump (CMJ), planned and reactive Y-shaped agility tests (PA, RA), and go/no-go task (GNG). Their subjective perception of fatigue was evaluated by visual analog scale. Fatigue induced by SSG (perception of fatigue increased by 41.56%, p = .001, g = 4.15) increased PA time (4.04%, p = .002, g = .97), RA time (6.45%, p = .003, g = 1.16), and number of errors in the response inhibition task (87.1%, p = .023, rc = .57), whilst decreased CMJ height (-6.65%, p = .014, g = .56). These performance deteriorations were not significantly associated with neither internal nor external load variables. However, a less pronounced drop in performance was related to external load variables, i.e., ∆CMJ height and ∆RA time correlated with very high-speed running (rs = .66, p = .006; rs = -.50, p = .022; respectively) and maximal speed (r = .54, p = .032; r = -.52, p = .037; respectively), whilst ∆PA time was associated with high-intensity accelerations (rs = -.76, p = .002). These findings indicate that fatigue induced by SSG affects both planned and reactive agility, decision-making in response inhibition task, and explosive strength in youth soccer players regardless of significant contribution of any robust internal or external load variables. Nonetheless, high-intensity actions within SSG partially compensate for the decrements in their agility performance and explosive strength. The load variables encountered during SSG do not fully reflect youth players' neuromuscular and perceptual-cognitive responses to sport-specific exercise.
