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 The great pretender: Multi-system tuberculosis and pathological fracture masquerading as a severe acute football groin injury – Case study with a 5-year follow-up

Reference: S Afr J Sports Med. 2023 Jun 2;35(1):v35i1a13980. doi: 10.17159/2078-516X/2023/v35i1a13980. eCollection 2023.
Authors: M Lichaba, W Diesel, D Constantinou
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10798602/pdf/2078-516x-35-v35i1a13980.pdf
Summary: In this clinical case, a man presented with a groin injury on his dominant side, which he apparently sustained in football (soccer) practice on the previous day. The man was unable to walk unassisted and had to be transported in a wheelchair. The consulting practitioner grew suspicious upon finding minimal clinical evidence and nothing notable on the X-ray to suggest a severe acute injury. A subsequent detailed workup revealed extrapulmonary tuberculosis (EPTB) of the musculoskeletal (MSK) and genitourinary tract (GUT) systems, complicated by a pathological fracture of the acetabulum, as the cause of the groin injury. Management of the EPTB resolved the condition with no relapse nor long-term sequelae beyond five years, despite being immunocompromised. We present the clinical case and a five year follow-up. The case serves as a reminder of the possibility that other conditions may mimic sports injuries and further illustrates a rare presentation of such a condition.

2 Analysis of the Sports Psychological Profile, Competitive Anxiety, Self-Confidence and Flow State in Young Football Players

Reference: Sports (Basel). 2024 Jan 8;12(1):20. doi: 10.3390/sports12010020.
Authors: José A Domínguez-González, Rafael E Reigal, Verónica Morales-Sánchez, Antonio Hernández-Mendo
Summary: The objective of this study was to analyse the correlations among the sports psychological profile, competitive anxiety, self-confidence and the flow state of young football players. Additionally, potential distinctions based on age category, competitive level and field position were explored. This study included 328 participants divided into two groups: Group 1, 14-15 year olds, and Group 2, 16-18 year olds (M = 15.85; SD = 1.44). Data were collected by using the Psychological Inventory of Sports Execution (IPED), the Revised Competitive State Anxiety Inventory-2 (CSAI-2R) and the Flow State Scale (FSS). The findings revealed positive associations between the sports psychological profile and self-confidence, as well as with the flow state. Conversely, competitive anxiety demonstrated negative relationships with the sports psychological profile, self-confidence and the state of flow. Moreover, superior scores were observed in the analysed variables for the older age category and higher competitive level, with no notable disparities based on field positions. These results underscore the interplay of psychological factors in the performance of football players and underline distinctions among players according to their category (age and level). This emphasises the importance of scrutinising these variables in athletes to comprehend their profiles and enable targeted interventions aimed at enhancing their psychological resources for competitive scenarios.

3 Follow-Up Weekly Training Distribution and Accumulated Internal Load Effects on Young Football Players‘ Well-Being, Physical Fitness, and Technical Performance

Reference: Sports (Basel). 2024 Jan 9;12(1):23. doi: 10.3390/sports12010023.
Authors: Yutthana Riansoi, Nuntapol Tongnillpant, Sakdarin Thammawong, João Ribeiro, Rodrigo Zacca, Phornpot Chainok
Summary: This study aimed to quantify the relationships among internal training load, wellness, physiological, isokinetic profile, and technical performance and assessed changes before and after a six-week pre-season structured combining physical fitness, small-sided-game and skill-based training program in young soccer players. Forty-five national-level young male soccer players (16.8 ± 0.9 years) were evaluated. There were no significant correlations between the wellness index and the physiological, isokinetic, or specific soccer skill parameters. Moderate correlations were observed between fatigue and stress (r = 0.47, moderate, p < 0.01), fatigue and average muscle soreness (r = 0.38, moderate, p = 0.01), and a large correlation between average stress and muscle soreness (r = 0.53, large, p < 0.01) were presented. All physiological, isokinetic, and technical parameters improved after a six-week pre-season training program (0.1 to -61.0%). Significant alterations in the physiological domain were observed after a six-week period, particularly in the fatigue index of the Bangsbo sprint test, YO-YO IR1 performance, and YO-YO peak La- (p < 0.01; -61.0%, 25.3%, and -19.8%, respectively). As such, the implementation of structured training and the monitoring of stress responses can lead to appropriate adaptation and balancing in the psychological and physical well-being of young national-level soccer players, particularly in the pre-season period.

4 Combined Turmeric, Vitamin C, and Vitamin D Ready-to-Drink Supplements Reduce Upper Respiratory Illness Symptoms and Gastrointestinal Discomfort in Elite Male Football Players

Reference: Nutrients. 2024 Jan 12;16(2):243. doi: 10.3390/nu16020243.
Authors: David J Clayton, Ross Burbeary, Connor Parker, Ruth M James, Chris Saward, Eleanor L Procter, William J A Mode, Carla Baker, John Hough, Neil C Williams, Harry Rossington, Ian Varley
Summary: Elite football is associated with the increased risk of illness, although targeted supplementation can reduce illness risk. This study assessed the effects of a supplement containing turmeric root within a black pepper and fat-soluble blend, vitamin C and vitamin D, on upper respiratory symptoms (URS), gastrointestinal symptoms (GIS), muscle soreness, and markers of inflammation and gut permeability in elite male footballers. Twenty-three footballers completed 3 weeks of no intervention (CON), followed by 16 weeks of daily consuming 60 mL of a commercially available supplement containing raw turmeric root (17.5 g, estimated to contain 700 mg of curcumin), vitamin C (1000 mg), and vitamin D3 (3000 IU/75 mcg) (SUP). URS and GIS were measured daily. Immediately (0 h), 40, and 64 h after six competitive matches (two in CON, four in SUP), the subjective soreness and plasma concentrations of creatine kinase [CK], c-reactive protein [CRP], and intestinal fatty-acid binding protein [I-FABP] were assessed. URS incidence (p < 0.001), GIS (p < 0.05), and plasma [I-FABP] at 0 h (p < 0.05) were greater during CON versus SUP. At 40 h, [CRP] was greater than 0 h during CON (p < 0.01) but not SUP (p = 0.204). There were no differences in soreness or [CK]. This study indicates that turmeric root, vitamin C, and vitamin D supplementation over 16 weeks can reduce URS, GIS, and post-match [I-FABP] in elite footballers.

5 Genetic Associations With Acceleration, Change of Direction, Jump Height, and Speed in English Academy Football Players

Reference: J Strength Cond Res. 2024 Feb 1;38(2):350-359. doi: 10.1519/JSC.0000000000004634. Epub 2023 Oct 6.
Authors: Alexander B T McAuley, David C Hughes, Loukia G Tsaprouni, Ian Varley, Bruce Suraci, Ben Bradley, Joseph Baker, Adam J Herbert, Adam L Kelly
Summary: High-intensity movements and explosive actions are commonly assessed during athlete development in football (soccer). Although many environmental factors underpin these power-orientated traits, research suggests that there is also a sizeable genetic component. Therefore, this study examined the association of 22 single-nucleotide polymorphisms (SNPs) with acceleration, change of direction, jump height, and speed in academy football players. One hundred and forty-nine, male, under-12 to under-23 football players from 4 English academies were examined. Subjects performed 5-, 10-, 20-, and 30-m sprints, countermovement jumps (CMJs), and the 5-0-5 agility test. Simple linear regression was used to analyze individual SNP associations, whereas both unweighted and weighted total genotype scores (TGS; TWGS) were computed to measure the combined influence of all SNPs. To control for multiple testing, a Benjamini-Hochberg false discovery rate of 0.05 was applied to all genotype model comparisons. In isolation, the GALNT13 (rs10196189) G allele and IL6 (rs1800795) G/G genotype were associated with faster (∼4%) 5-, 10-, and 20-m sprints and higher (∼16%) CMJs, respectively (p < 0.001). Furthermore, the TGS and TWGS significantly correlated with all performance assessments, explaining between 6 and 33% of the variance (p < 0.001). This study demonstrates that some genetic variants are associated with power-orientated phenotypes in youth football players and may add value toward a future polygenic profile of physical performance.

6 Longitudinal development of physical, perceptual-cognitive and skill predictors of talent in academy and professional female football players

Reference: J Sports Sci. 2024 Jan 23:1-8. doi: 10.1080/02640414.2024.2307804. Online ahead of print.
Authors: Adam Beavan, Jan Spielmann, Stefan Altmann, Sascha Härtel
Summary: Existing literature on talent development predominantly focuses on male athletes, with limited representation of female athletes. This study aims to address this gap by examining the long-term development of female football players in an elite club. Routine lab-based assessments were conducted on 238 athletes across six teams for 7 years to determine how physical, perceptual-cognitive, and skill performance predictors fluctuated with player age and developmental stage (sampling 9-11y, specializing 12-14y, investment 15-18y, and performance +18y). The developmental stage was a significant predictor of improved performance for each talent indicator (p < .001), with each consecutive stage significantly outperforming the previous stage in all domains with moderate to large effect sizes (0.07-0.40 ηp2). Improvement rate was higher in young adolescence (<15) and slower approaching adulthood (>18y). Playing position influenced performance scores on several physical and technical skill predictors (p ≤ .001), but not perceptual-cognitive ones (p ≥ .11). Players progressed continuously from the sampling to the performance stage, contradicting previously reported plateaus observed when athletes reached the investment stage. Benchmark data are provided across age and playing position to better understand what is required for successful participation at an elite level at varying age groups in female soccer.

7 Effectiveness of an On-Field Rehabilitation framework for return to sports in injured male professional football players: a single-blinded, prospective, randomised controlled trial

Reference: BMJ Open Sport Exerc Med. 2024 Jan 19;10(1):e001849. doi: 10.1136/bmjsem-2023-001849. eCollection 2024.
Authors: Ioannis Stathas, Alkiviadis Kalliakmanis, Afxentios Kekelekis, Despoina Danassi Afentaki, Elias Tsepis, Konstantinos Fousekis
Summary: In football, on-field rehabilitation (OFR) is critical during injury recovery for a player’s safe return to sports (RTS). The study aimed to evaluate the effectiveness of an OFR framework for RTS in injured male professional football players. A prospective block-randomised controlled-parallel trial was conducted (level of evidence 1b). Male professional football players (mean age, 26.3±3.6 years) from Greece diagnosed with an acute, lower limb musculoskeletal (MSK) injury (confirmed clinically and through imaging) participated in the study. During rehabilitation, the participants‘ OFR was guided by either the On-Field Rehabilitation (On FI.RE.) accelerated framework (experimental group) or a traditional OFR framework for a late injury recovery phase (comparison group). Between July 2021 and January 2022, 76 players were randomly allocated to the experimental group (n=38) and the comparison group (n=38). Participants were blinded during the study regarding intervention therapeutic protocols. The primary outcome measure was the effect of On FI.RE. framework on the time needed to return to team training (RTT) participation. The correlation between the time needed to return to on-field activity and RTT was calculated. Subsequent injuries were registered for a 12-month follow-up period. The intervention protocol, On FI.RE. framework, had a statistically significant effect on the time needed to RTT (F(1) = 49 626, p<0.001) with a large effect size (ES; η2=0.422) and fewer days (mean=23.8±9.1 days) needed than the comparison group (mean=30.3±9.8 days). There was a strong correlation between return to on-field activity and the time needed to RTT (r(76) = 0.901, p<0001) with a large ES (r>0.5). Six subsequent injuries were registered in the traditional OFR framework group, and one subsequent injury in the On FI.RE. framework group after a follow-up period of 12 months. The On FI.RE., an accelerated OFR framework during injury recovery, is more effective than a traditional OFR framework, reducing the time a player needs to RTS. It entails a very low risk of reinjury.

8 Examination of the validity of the Injury-Psychological Readiness to Return to Sport (I-PRRS) scale in male professional football players: A worldwide study of 29 professional teams

Reference: J Sports Sci. 2024 Jan 25:1-9. doi: 10.1080/02640414.2024.2307764. Online ahead of print.
Authors: Gordon Dunlop, Andreas Ivarsson, Thor Einar Andersen, Susan Brown, Gary O’Driscoll, Colin Lewin, Gregory Dupont, Clare L Ardern, Barthelemy Delecroix, Leslie Podlog, Alan McCall
Summary: Perceived confidence is an important dimension of an athlete’s psychological readiness to return-to-play. However, there is no established and validated tool to evaluate confidence in professional football. This study aimed to provide preliminary evaluation of the internal structure of the Injury-Psychological Readiness to Return-to-Sport scale (I-PRRS) in a cohort of injured male professional footballers. Over an 18-month period, 29 teams from 17 leagues participated. Players sustaining injuries eliciting ≥≥ 3 weeks‘ time-loss were recruited. Cross culturally adapted to 4 further languages, the I-PRRS was administered on two occasions: 1) day before returning-to-training and 2) day before returning-to-match-play. In total, 113 injuries were recorded with 96 completed I-PRRS data sets collected. Confirmatory factor analysis indicated the I-PRRS was a unidimensional scale, with all items measuring the same construct. The scale demonstrated good internal consistency (ω = .88). When examining longitudinal invariance of the I-PRRS across administration time-points, indices of model fit supported scalar invariance. There was preliminary evidence of good internal structure for the I-PRRS in professional male footballers. However, before further research involving the I-PRRS can be endorsed, efforts to confirm or refute empirical developments pertaining to psychological readiness are necessary.

9 Individualized monitoring of longitudinal heading exposure in soccer

Reference: Sci Rep. 2024 Jan 20;14(1):1796. doi: 10.1038/s41598-024-52163-8.
Authors: Rebecca Kenny, Marko Elez, Adam Clansey, Naznin Virji-Babul, Lyndia C Wu
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10799858/pdf/41598_2024_Article_52163.pdf
Summary: There is growing concern that repetitive soccer headers may have negative long-term consequences on brain health. However, inconsistent and low-quality heading exposure measurements limit past investigations of this effect. Here we conducted a comprehensive heading exposure analysis across all players on a university women’s soccer team for over two calendar years (36 unique athletes), quantifying both game and practice exposure during all in-season and off-season periods, with over ten thousand video-confirmed headers. Despite an average of approximately 2 headers per day, players‘ daily exposures ranged from 0 to 45 headers, accumulating to highly variable total exposure of 2-223 headers over each in-season/off-season period. Overall, practices and off-season periods accounted for 70% and 45% of headers, respectively. Impact sensor data showed that heading kinematics fell within a tight distribution, but sensors could not capture full heading exposure due to factors such as compliance. With first-of-its-kind complete heading exposure data, we recommend exposure assessments be made on an individual level and include practice/off-season collection in addition to games and competitive seasons. Commonly used group statistics do not capture highly variable exposures, and individualized complete heading exposure tracking needs to be incorporated in future study designs for confirming the potential brain injury risk associated with soccer heading.

10 Relationship between dynamic visual acuity and static visual acuity, refractive error, and binocular vision in elite soccer players

Reference: Clin Exp Optom. 2024 Jan 21:1-6. doi: 10.1080/08164622.2024.2301981. Online ahead of print.
Authors: Jorge Jorge, João Pedro Jorge
Download link: https://www.tandfonline.com/doi/epdf/10.1080/08164622.2024.2301981?needAccess=true
Summary: In many sports, dynamic visual acuity is used. In order to improve dynamic visual acuity, it is important to understand the aspects of the visual system that can cause compromise. The aim was to investigate the parameters of the visual system that may influence dynamic visual acuity in professional soccer players. In 2022, 40 professional players were analysed. Screening consisted of a survey, the measurement refractive error, and static and dynamic visual acuity and the binocular vision parameters. All athletes were men with a mean age of 24.9 ± 4.8 years. The mean refractive error was -0.29 ± 0.61D, and 22.5% of athletes are myopic only and 7.5% hyperopic. Static visual acuity was R: -0.037 ± 0.094 LogMAR , L: -0.036 ± 0.098 LogMAR. Dynamic visual acuity was 0.154 ± 0.118 LogMAR . There is a positive and moderate correlation between monocular static visual acuity and dynamic visual acuity, with r = 0.524 (r2 = 0.275 , p < 0.001) for the right eye and r = 0.553 (r2 = 0.306, p < 0.001) for the left eye. For the component of astigmatism (J = 0) and for stereopsis in distance vision, the correlation was, r = -0.472 (r2 = 0.223, p = 0.002) and r = -0.467 (r2 = 0.218, p = 0.002), respectively. Athletes with lower static visual acuity in distance vision, or with worse stereopsis in distance vision or more myopic astigmatism, have lower dynamic visual acuity than other athletes.

11 Effects of peppermint oil inhalation on vertical jump performance in elite young professional soccer players: A double-blinded randomized crossover study

Reference: Heliyon. 2024 Jan 10;10(2):e24360. doi: 10.1016/j.heliyon.2024.e24360. eCollection 2024 Jan 30.
Authors: Alex Ambrosio Rites, Pablo Merino-Muñoz, Fabiano Ribeiro, Bianca Miarka, Veronica Salermo, Diego Viana Gomes, Ciro José Brito, Esteban Aedo-Muñoz
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10826725/pdf/main.pdf
Summary: The aim was to evaluate peppermint essential oil (PEO) inhalation’s effect on young soccer athletes‘ motor performance. A randomized crossover design was used to test the effect of the PEO. Eleven U-17 soccer players were evaluated into two conditions (PEO and Placebo – PLA). The players were tested in squat jump and countermovement jump and inhaled PEO or PLA and 10 min later performed the physical tests again. A mixed ANOVA was performed to test the hypotheses. Main effects were found for the time in jumping height in the CMJ (p = 0.037). No main and interaction effects were found in the SJ variables. From the results, decrease CMJ performance acutely, both conditions presented decrease in JH, but based in effect size, PLA decrease is higher (more sample size for corroborate this) possibly due to improvements in the eccentric yielding sub-phase, where mentioned phase could be reflecting neural changes (required experimental verification). The PEO could be the interest in trainers for use before of match or in the half-time for minimize the decreased of physical performance by the rest.

12 An ecological approach for skill development and performance in soccer goalkeeper training: Empirical evidence and coaching applications

Reference: J Sports Sci. 2024 Jan 31:1-12. doi: 10.1080/02640414.2024.2306449. Online ahead of print.
Authors: Elliot Bastias, Fabian W Otte, James Vaughan, Scott Swainston, Mark O‘ Sullivan
Summary: Ecological approaches in sport consider that athletes adapt to properties of the task and the surrounding environment. Thus, task and environment are key constraints of performance. Yet, the influence of task and environmental constraints on athletes‘ performance needs empirical examination, especially in sport-specific contexts such as soccer goalkeeping. This study aimed to examine if and how task and environmental constraints influenced goalkeepers (GKs‘) performances. We monitored performance coefficients of two professional female GKs across 13 training tasks that varied based on 9 constraints, referring to both interactions among athletes and properties of the surrounding landscape. Results showed that constraints explain ~ 47% of the observed variability in GKs‘ performances. Numerical complexity (i.e., the potential interactions between athletes) showed a major influence on performance, which indicates that number of interactions among athletes may constrain GKs‘ perceived opportunities for action. Field dimensions and landscape representativity (including elements such as penalty area(s), target goal(s) and constraints for shooting) showed positive relationships with performance, supporting that training designs retaining closer proximity to the game may benefit GKs‘ performances. Overall, results supported that athlete-environment couplings could be understood as a multifactorial model and hence, a combination of task constraints are necessary for designing effective learning environments.

13 Jump and sprint force velocity profile of young soccer players differ according to playing position

Reference: J Sports Sci. 2024 Jan 31:1-12. doi: 10.1080/02640414.2024.2307768. Online ahead of print.
Authors: Dhia Ben Hassen, Firas Zghal, Nicolas Peyrot, Pierre Samozino, Haithem Rebai, Abderrahmane Rahmani
Summary: Our study aimed to compare explosive performance and underlying mechanical determinants explored through F-V profiles in jumping and sprinting among young soccer players based on their playing position. Ninety elite soccer players were categorized into the following positions: goalkeepers, central defenders, wide defenders, central midfielders, wide midfielders, and forwards. Two testing sessions were conducted to measure the 30-metre sprint time (T30) using an over-ground sprint test and jump height (Hmax) through the SJ test. Results demonstrated performance variations among positions. In sprinting, forwards showed greater T30 (4.5 ± 0.14 s) compared to other positions, with goalkeepers exhibiting the lowest T30 (4.86 ± 0.18 s). Forwards also displayed higher maximal theoretical velocity (8.8 ± 0.4 m.s-1) and power output (Pmax) (19.4 ± 2.6 W.kg-1) than other positions, while goalkeepers had the lowest Pmax (16.5 ± 2 W.kg-1). In jumping, forwards (33.2 ± 3.9 cm) and wide-midfielders (33.6 ± 3.8 cm) achieved higher Hmax compared to goalkeepers (29.2 ± 5 cm) and central-midfielders (29.2 ± 3.8 cm). Wide-midfielders (28.5 ± 4.8 W.kg-1) and forwards (27.1 ± 4.3 W.kg-1) surpassed goalkeepers (23 ± 2.8 W.kg-1) and central-midfielders (25.1 ± 3.8 W.kg-1) in Pmax. Our findings reveal substantial position-related disparities in F-V profiles among elite young soccer players, in sprinting and jumping emphasizing the need for position-specific training programmes to optimize player development and on-field performance from an early age.